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City Council Agenda Packet 06-12-1995 SpecialAGENDA SPECIAL MEETING - MONTICELLO CITY COUNCIL Monday, Jane 18, 1898 - 6 p.m. Mayor. Brad F yle Council Members: Shirley Anderson, Clint Herbst, Brian Stumpf, Tom Perrault Call to order. Consideration of selecting engineering firm for wastewater treatment plant expansion. Adjournment. Soerial Meeting/kbrkshop for selection of engineering consultant for expansion of the Citv of Monticello's Wastewater Trentnent Facilitv. (.).S. ) A. REFERENCE AND BACKGROUND, At the May 22nd meeting, the Council reviewed proposals and interviewed four engineering consultants to be considered for expansion of the City's Wastewater Treatment Facility. At the conclusion of that meeting, Staff was directed to prepare additional questions and gather additional questions from the Council and Mayor, forward those to the consultants for their answers and develop a rating structure to be used to evaluate the proposals. In addition, City Staff was to use this rating structure to evaluate the firms and report to the City Council. A list of questions, (several for all of the firms and a few specific to each individual firm) was faxed and mailed to the consultants on June 1st, and also sent to the City Council. Two of the firms responding requested staff time so that they could give their responses verbal ly as well as in writing. We then provided this opportunity to the two remaining firms and, consequently, the Staff re -interviewed all four firms for 1 to 1 1/2 hours each during the past week. Based upon these interviews and additional information provided by the consultants and their original proposals, City Staff has come to a few conclusions. We feel that our goals should be to have a less complex plant than we currently have, one that is simpler and easier to operate, that can be more easily expanded, and offers less areas in which to produce significant odors. Finally, we must be able to do this for a reasonable cost (i.e., cost effectively) and we think it must include class 'A' sludge, we bel ieve that two other alternatives offer the City better opportunity to meet the goals listed above, and that the alternative previously supported in the Facilities Plan by City Staff and the consulting engineer would not accomplish these goals. The two alternatives we feel that should be studied further are an oxidation ditch and a sequencing batch reactor. Both of these options offer a facility that would be less complex, less l ikely to produce odors, easily expandable nod, we believe at a lower capitol cost than the alternate in the Facilities Plan, (even when adding the option of a class 'A' sludge, which would be a process in which the sludge could be applied or sold as purely an agricultural product). In order to select one of these alternatives, we feel that both alternatives need to be studied in depth and offered as an amendment to the Facilities Plan. In order to rate or evaluate the, proposals, City Staff has developed a rating structure based upon oeveral comp menta of the proposals, the interviews and the answers to the additional questions. A copy of that rating structure Is enclosed for your review. Please feel free to rate each one of the proposals yourself and/or use, the Staff's rating evaluation process. The Staff's ratings will bn provided at the workshop ,in Mondry eveninu. You will find enclosed under a separate cover copies of the ❑ddltional angwerq Iran the questions you receival th.i previous wet -k. M, ilii UM241-M \Q�5 I . The first alternative would be to select a consultant based upon the Cts n� original proposals, interviews, answers to additional questions, and f` your own individual ratings and/or that provided by Staff. J 2. The second alternative would be to select a consultant based upon the above as well as any other criteria suggested by the City Council including that gut feeling that a specific consultant would do the best job for us. The third alternative would be not Fo select a consultant at this time but request Staff to do additional investigative work regarding one, two or more consultants and, report back to the Council at a later date. COl41ENDATION t It is the Staff's opinion that we have gathered enough information and received answers to enough questions for the Council to make a selection of an engineering consultant. It is anticipated that after the selection is made, we will have an opportunity to further investigate that consultant's past projects and facilities during the contract negotiation Stage. D. SUPPORTING DATAi Copy of the rating and proposal evaluation form as developed by City Staff. Copy of the answers to questions will be provided under separate cover due to their bulk. J WASTEWATER TREATIENT PLANT PROPOSAL RATING STRUCTURE i I. Proposal & Subsequent Questions & Answerst A. Completeness, does it address main issues? B. Work plan, does it accomplish City goals? C. Innovativeness, does it approach project from all angles? Possible Points _20 II. Knowledge of the Project Requ irementst A. Does the consultant understand the existing problems and conditions? B. Does the consultant understand the City's needs and goals and expectations? Possible Points 15_ III. Experience and Ability, A. Does the consultant have previous experience with similar projects? B. does the consultant have a working knowledge of the options they are proposing? C. Is their experience both previous and current? D. Does the firm have depth? Who would take over in event the project manager and project engineer were not available? Possible Points 20 IV. Interview: 1 A. Was the consultant able to communicate his proposal and ideas easily? B. Were the project's main players present at the interview? C. Was the consultant enthused or excited about the project, do they really project their eagerness? D. Did they have confidence in their ability to do the project? Did they project that confidence? Do you have confidence in them? Possible Points 10_ V. Project Costa A. Was the estimated project cost reasonable? Has it beyond comprehension? did they support their figures with rational approaches? Is the proposed project cost effective? B. Were the engineering fees reasonable? Possible Points 9_ VI. Ability to Whrk MnPCA. A. Did the consultant present a reanonable approach to working with the Kr PCA and Staff? B. Did the consultant offer more support In this area than others? Possible Points 10 prommULUMMI ANSWERS TO QUESTIONS OF CITY OF MONTICELLO BY TKDA, INC. June 7,1995 A. GENERAL QUESTIONS Contract documents would require the Contractor to maintain a record copy of all Drawings, Specifications, and Addenda and to mark them to show all changes made during construction. These documents are reviewed by the Construction Inspector, who will also have marked up a set of documents, to help to assure that all changes have been documented. Other documents in addition to updated construction plans and specifications may also be incorporated into the record set. For example, Contractor prepared electrical connection drawings can be added to the record drawing set to supplement the Engineer prepared drawings. The State Revolving Loan (SRF) Program allows for inclusion of allowance costs, which include administrative, legal, facilities planning, and detailed design. There is no limitation on these costs, but they must be well documented for audit purposes. We would assist the City in preparation of the project cost breakdown for determination of total project costs for the loan application. Any facilities planning costs for which the City has documentation can be included. Yes. Normally this is done monthly during construction, in conjunction with the Contractor's monthly partial payment request review and approval. More frequent written reporting of project progress can be communicated to the City upon request. Construction inspectors routinely make daily and weekly written reports regarding consuuction progress. During preparation of plans and specifications, written reporting is normally monthly, in conjunction with our monthly invoice. More fiequem written reporting could be prepared U desired. TKDA has emphasized project management through in-house training and use of a project management guideline manual. Project management requirements are addressed in a general nature, recognizing that projects vary widely in size and with respect to involvement of multiple disciplines, ie. environmentallprocess, mechanical, electrical, structural, architectural, civil. A project management manual per se is not used and applied directly to any particular project in "cookbook" fashion. Our approach is to appropriately train and equip Project Managers to do the work as required for each project encountered. Therefore, we do not have a project man:Wmem manual to provide to clients. if You have indicated that SRF loan financing would probably be used. To be added to the Intended Use Plan (IUP), the list of projects that will receive funding, the City must have a Facilities Plan that has been approved by MPCA. MPCA's involvement would begin with submission of a facilities plan, which may be multiple documents, that meets all of their requirements, and other documents appropriate to their facilities plan review process. These include descriptions of public meetings held, existing and future wastewater flow and loading data on MPCA fonts, signed letters of intent from significant industrial users, descriptions of estimated annual sewer service charges for an "average residential user", description of how interim treatment during construction will be accomplished with adequate treatment provided, a list of public notice addresses used on an MPCA forth, a detailed summary of a public hearing on the proposed project, a formal resolution of the City Council adapting the facilities plan, and completed environmental information sheets. Subsequently MPCA must review and approve the plans, specifications and contract document through which the project would be constructed. We would also attempt to work with MPCA to accelerate their normal plan and specification review time, which by law cannot exceed 90 days, but which often takes that long due to work overload. We have successfully involved MPCA in phased review for Albert Lea and Luveme. Whether we could do this again is beyond our direct control, but it would he attempted. In general, bidding during she winter affords the possibility of construction staring at the earliest opportunity in the spring. The advantage is that this may allow completion of construction to enable further construction inside, more suited to winter conditions, to proceed at that time. This is nota matter of bid competition, however. It is very difficult to predict reliably when will be the best time to take bids to maximifte bidding competition. We did not propose screening to eliminate primary clarifiers as we don't think that it could he advantageous to Monticello. BOD removal from screening would be less than from operation of good primary clarifiers and maximizing BOD removal in the primary process would appear to be important for Monticello's situation with a raw wastewater BOD concentration greater than that of normal domestic strength wastewater. 5041 8. Nitrification can be achieved in trickling filters through loading control and in the oxidation ditch process we have described. Nitrification to meet receiving stream ammonia limitations is achieved via the oxidation ditch processes at Wadena and Luveme. Phosphorus removal via chemical precipitation could be added to virtually any process that would be employed. Modifications to encourage biological removal of phosphorus could also be investigated. Activated sludge processes probably afford greater biological phosphorus removal potential than trickling filter processes. 9. Yes. We have not estimated costs for operations and training space and odor control ourselves. We assumed that facility costs for operations and training space were included in the Facilities Plan as part of the new sludge pumping facility, which appeared to be sufficiently large on drawings and which had a somewhat large cost estimate of $700,000. The Facilities Plan included a cost estimate for odor control at $1,400,000 that appeared to us to be probably more than adequate. We have not taken the time to look at details, but agree that these mattcis need to be addressed and included in an appropriate way. 10. Advantages: Interest rate may be lower than bond rate paid by the City. Finance term can be 20 years. Loan can cover planning and design costs. City's bonding capacity is not affected. Disadvantages: City must prepare MPCA approvable Facilities Plan. City must comply with State/Federal SMWBB requirements. Contractors must adhere to higher of State or Federal minimum wage rates. 11. Suggestions that we have trade should allow lower O&M costs. 71W suggestions were made to effect construction cost savings and to simplify the process from an operation and maintenance standpoint. 12. We have described in our written proposal two grant programs sponsored by NSP that relate to energy. 13. Change orders would not result in additional engineering cost to the City unless they were the clear and direct result of a City requested change involving additional scope of work and engineering costs. -3- B. TKDA SPECIFIC QUESnONS Construction costs and operating energy costs are reduced by reducing the oxidation ditch size without seriously compromising its shock loading and basic treatment efficiency capacities. The detention time would still be quite long for the activated sludge process (between 12 -15 hours) affording a significauu capacity for dealing with possible shock loads. The proposed oxidation ditch design can be accommodated on the land that the City owns next to the existing plant. 2. We believe that the SDR process could have advantages for Monticello. Although we did not mention it in our proposal, primarily to avoid making the proposal too complicated, we discussed the SBR process potential. We thought the reasons cited for its not being investigated on page 4 - 7 of the Facilities Plan report were net particularly valid. We would be happy to investigate the process in a Facility Planning mode should we he selected and asked to do so. The SBR process could possibly result in significant construction cost savings with utilization of some of the existing tanks, although possibly at the expense of complicating the interum treatment during construction. We believe that the engineering costs for investigation and evaluation of the SBR process could be minimized by appropriate use of equipment manufacturer's process design and cost estimating serv'ires. lust last year in a prelim inary engineering study for a smaller municipal wastewater treatment facility we analyzed the feasibility of upgrading an existing trickling filter plant alter another engineer had recommended an all new plant after dismissing the upgrade project without much evaluation. We looked it SBR as an alternative, relying on an equipment manufacturer's recommendmions for the process, without much additional engineering on our pan. While not less expensive than a s impler trickling filter upgrade, the upgrade using the SBR process with all new tanks and equipment was estimated to be significantly leas expensive than the lowest cost all new facility estimated by the other engineer. 11e impact of the secondary process selection, in this case oxidation ditch or trickling fdter/solids contact, is considered relatively insignificant regarding odor control. Liquid stream process components upstream from the secondary process and the sludge stream processes would receive the primary emphasis for odor control. Generally, the occurrences of odors are related to the headworlu and primary clarifiers when the condition of the wastewater is such that radors are prevalent. Also, any handling of the plant sludge or digester supernatant which is exposed to the air is a potential odor source. -4- tS75 VAOIW6CENTERPRhE.2WSEMCENTMSr PAL&AdNWI10 LT2A� &YIPS -2M ARCMIrECnM U46*ERV4 ENYrtIYNAffNrAL TRN SFORTATFON Rli: MonttoellaM J UNE - a , 19 9 4 VVNRF Expettsim SEH Re W P-MONTWXI Mr. John Stmda: Publk wods Dbramr city of Monticello 25013ast Broadway Mondetilm INPh 33367r9W Dear Mr. Sdmola: This Is to provide additional information of the potential for producing a Class A sludge in conjurtctlon with the aerobic digests m alternative we disotssed in our proposal. The USEPA has identified several sludge treatment methods as'Poxesses to Further Reduce Pathogens' MR) , which be definition result in a Class A sludge. One method, thermophilic aerobic digestion, is a refinement of the conventional aerobic digestion process. The Part SW PFRP description of thermophilic aerobic digestion is: Lquid saoW sludge is agitated tnilh air or oMen to maintain &vob(c conditions and meant cell rpfdertce time OF the serogge sludge is 10 days at 55 - 60 degrees C (131-140 degrm F). The basic difference between this and conventional aerobic digestion is that the temperature is significantly higher and the detention time is sWufuantly less. An aerobically dtgested Gass B sludge Is must be maintained at 68 degrees F for 40 days or 60 degrees F for 60 days. The higher temperature required for the Class A sludge will signiRcar►tly increase the UIrU requirements per gallon of sludge, but the total volume to be heated is reduced 75.83%. Other potential cravings may include reduced swrage requirements as the Class A sludge can be land applied under less stringent regulations. This is certainly an option that should be evaluated. An additional alternative that should be evaluated is pasteurisation. Tho Part 503 definition of pasteurization is: 7fte ten� of the sludge b nrointa ked at 70 degrees C (158 degree F) for 30 mbudeo or longer. This process is not very common in the Unities State, but is widely used in Europe. Steam is generally used to heat the sludge though hen exchanges are treed in some applications. This process will likely require new fac"It' a but could be cost effective in the long run. VOWALloTr NDda rCKKW NC. hwoso ul MN tr acro. NU O WWWA ft" W ►MOWN, VA IAV Gourrr, a aqua OPPOR,1r EARomm Uw There are other sludge treatment processes that involve heating the sludge, including heat treatment, but these generally require signamrttly higher temperatures and require specialized equipment. 'fire thermophilic aerobic digestion process will amximize use of the existing fadUties and probably resulting in the loest wconstruction costa. Pastuerization may have a higher capitol cost but lower operating costa We will evaluate both of these processes in out initial ground work phase, and compare the relative casts and benefit to convediond aerobic digestion. Again, we would like to dunk you and your staff for taking the time to zr► with us. We sincerely look forward to working with you an this project. Si�nOasely, Hobert W. Stmt., P D ®M� June 8,1995 Mr. John Simola Public Works Director City of Monticello 250 East Broadway Monticello, MN 55362-9245 Dear Mr. Simola: 3575 VAONAIS CENTER ORNE. 20J SEM CENTER, ST PALL. AN55110 61249, ARCMTECTLAE ENOWEERWG ENVIROWE'NTAL RE: Monticello, Minnesota WWTP Improvements SEH No. P-MONTI9501 Short Elliott Hendrickson Inc. (SEH) appreciates the opportunity to provide the additional information you requested for our proposal for the Wastewater Treatment Plant Expansion for the City of Monticello. Project 093-14C. In our response to your second SEH specific question regarding completion of the Facilities Plan we indicated that we would provide a copy of the check list that the MPCA uses in their review of Facilities Plans. This document is 30 pages long and rather than fazing it, we will provide a copy when we meet tomorrow. Again, we appreciate the opportunity to provide this information to you and look forward to discussing this project with you again tomorrow. Sincerely, / J /1,-cA�O (Q� ohn H. Stodola, P.E. Manager, Wastewater Department nn ;Gar Eu:nrr '+f•.2F:�:��,'bJ W1; A1.7..�APlAC71IW zd-��k Robert W. Stark, P.E. Project Manager ST CICUO AW C.K/TtWA I4LLS *7 UA=11V M7 uAECOUNry w EQUAL OF;YCnrUN1rY C",Ao ER Questions for all companies 1. How would changes to the project be documented to ensure quality "as•builts'"1 SEH prepares as-builts using information obtained from a variety of sources. Our contract documents require the Contractor to maintain project record drawings onsite that document all changes, including addenda, change orders and field modifications. These must be submitted to the Owner prior to the final pay request. A copy of the specifications detailing this requirement is attached for your review. Char Resident Project Representatives (inspectors) also independently document changes that occur over the course of a construction project. These drawings will also typically locate underground utilities using measurements from known or surface visible objects. These records together with the Contractor's will ensure that all changes are thoroughly documented. The as-builtts are prepared to the level of detail that each individual client desires, ranging from simply notating any changes to complete re -drafting the individual sheets to the as -built condition. L Can your firm be sure to include the Facility Plan costs in PFA apprs.? SEH has considerable experience in all financing options that could be available for Monticello. The Public Facility Authority (PFA) will finance all costs associated with the Facility Plan and any revisions in the frtal loan package. Costs associated with any interim projects or improvements needed prior to the primary project can also be financed if the following criteria are met: 1. A public hearing is held regarding tlu: overall project; 2. A council resolution is adopted regarding the interim improvements; and 3. The interim improvements are initially financed with taxable bonds or city generated funds. The PFA will then include the interim projects in the overall financing package. The PFA will ppl refinance any tax exempt short term bonds. The aforementioned requires extra effort and coordination that SEFfs financial assistance staff will coordinate with City staff at no additional fee. 3. Does your firm prvvide written reporting of project progress on a regular (weekly -monthly) basis from plans and specs through construction? Our approach is to involve our clients as integral players on our project teams throughout planning, design and construction phases. We make a real effort to keep our client's staff not only informed on project progress and status, but also involved in the decision making processes to the extent they desire. Client staff will be informed of and welcomed to attend any project related meetings (regulatory personnel, construction personnel, etc,) and provided with minutes for all meetings. whether they attend or not. Additional project progress documentation is provided to the extent desired by Individual clients. Typically, a monthly progress report will be given to the Director of Public Works and his staff, and also to the City Council at a scheduled council meeting. Depending on the stage of the project, and the work accomplished, these reports may be more frequent. Does your firm use a project management manual? If so, do you provide such a document to clients? What is typically of its content? SEH does have a Project Managers Handbook that is provided to all project managers. This handbook was developed by adapting the PSMJ Project Managers Manual to address SEH's specific needs. The handbook is periodically revised and updated, with the most recent revision completed in November, 1994. This document is available for viewing by clients, though some portions are confidential. The chapter titles are listed below: 1. Introduction 2. What is Project Management 3. Proposals 4. Contracting S. Project Planning 6. Project Staffing 7. Project Startup 8. Project Phases 9. Scheduling 10. Budgeting 11. Monitoring and Control 12. Quality Assurance/Quality Control 13. Project Financial Management 14. Construction Contract Administration 15. SEH Closeout The Introduction (Chapter 1) to the manual further describes its purpose and use. A copy is attached for your information. SEH also provides formal training to its project managers and engineers through the University of St. Thomas Business Management Center. These classes are generally offered after hours at our offices and represent a joint commitment by the company and employees. S. At what point In time does your firm propose to involve the MPCA and to what degree? Our normal approach to working with the Minne;ota Pollution Control Agency (MPCA) is to involve the MPCA review staff early on and maintain regular communication throughout the entire planning and design process. This approach has significantly reduced the time required for MPCA review and minimizes the MPCA's modifications. The recent Becker wastewater treatment plant expansion is a prime example on how this interactive process can work. This plant expansion was a large complicated project (construction cost $7,000,000) that included doubling the domestic treatment capability and adding capacity to treat a high strength industrial waste (9100 pounds BOD per day). The total time available from initial planning to substantial completion of construction and initiating operation was 18 months. MPCA review and approval was required for several phases, as listed below: • Initial determination of effluent limits • Review and grant variance from non -degradation effluent limits • Review and approve Environmental Assessment Worksheet • Review and approve design report • Review and grant air emissions permit • Review and approve plans and specifications • Review sludge management plan The MPCA staff were kept informed and provided input to the planning and design process through regular meetings. This enabled our project team to address their concerns during the planning and design process, rather than after their formal review. It also enabled the project to continue during the review period. The MPCA staff associated with this project are identified below, should you wish to contact them. It should be noted that this approach was not a one time occurrence, but rather, is our preferred mode of operation. William Priebe, P.E. - Design reports, plan and spec review (612)296-7150 Craig Affeldt - HAW review (612) 296-7796 Greg Gross - Effluent limit variance (612)296-7213 6. Is there a better time of the year for the most competitive bids on the project, and what Impact on the bids would your proposed time -line have, if any? Two factors that play significant roles in construction bids are the total time allowed for construction and time of the year over which the major outside work is to be accomplished. It is generally believed that it is best to bid jobs involving major excavation, concrete and masonry work in the late winter and allow maximum use of the following construction season. This type of construction is las costly in the summer as it is not necessary to deal with frost or provide heat for construction activities. This type of schedule also allows most structures to be dosed in and interior mechanical, electrical and process equipment installation can occur over the winter. The time allowed for construction is important because it allows the contractor to optimize the utilization of his manpower and equipment. The schedule contained in our proposal was based on these assumptions. The interim improvements were shown to bid during March, 1996 and be constnuted during the following summer. The main project would bid during March 1997 and be constructed over the following year and a half. It would be possible to compress the construction schedule, however this would likely increase the cost and does not appear to offer any significant advantages as the proposed schedule meets the estimated wastewater treatment needs. 7. To those who proposed screening to eliminate primary clarifiers, please discuss quantities and how final disposal might be accomplished. Fine screens have become an acceptable alternate to primary clarifiers with improvements to screen cleaning and screenings dewatering equipment. The amount of screenings varies widely from plant to plant, but text book estimates of 4-8 cubic feet per MGD can be used as an initial estimate. We would propose that a screenings press be installed in conjunction with the screen(s) to reduce the free water. These presses allow the screenings to be dewatered to the point that they will pass the EPA "paint filter test" and be suitable for disposal in a permitted solid waste landfill. The screens and presses will also substantially reduce the amount of sludge generated, thereby reducing the required digester capacity. 8. Assuming future nutrient limits are enacted for Monticello and that they too will be high and variably loaded to the facility, how easily is your proposed system modified to accommodate/treat for nutrient limits? The oxidation ditch is capable of both ammonia and phosphorus removal on a year round or seasonal basis. Historical data from numerous oxidation ditch facilities indicates that almost complete nitrification occas and reduces the ammonia nitrogen to 1.0 mg/1 or less. A positive dissolved oxygen for an extended period of time is required to achieve appreciable amounts of nitrification. These conditions exist in an oxidation ditch process which is an extended aeration process. In comparison, an SBR process will not have high dissolved oxygen levels until the end of the React cycle which may make obtaining complete nitrification more difficult. Phusphurub remuvai can either be accomplished through biological or chemical removal. Biological removal requires that the dissolved oxygen content in the mixed liquor be varied and allowed to go to 0 mg/1 during portions of the treatment process. This can be accomplished in a oxidation ditch as the air is added at discrete locations in the tank and is consumed through out the remainder of the tank. Some facilities use a selector, which is a small tank in which influent and return sludge is mixed without oxygen prior to introduction to the aeration tank. This also helps with bulking associated with filamentous sludge. Chemical phosphorus removal is accomplished through adding a precipitant to the waste stream, causing the phosphorus to precipitate and be removed with the sludge. This process is generally more expensive, but also more reliable and is often indudcd as a backup to biological removal. Either process can easily be adapted to an oxidation ditch. 9. Does your estimated project cost include expansion of operations and training space, handicapped accessibility where required, reasonable odor control, and a plant that can take a peak instantaneous wet weather flow of 5.19 MGD las per the Facility Plan)? The estimated project costs include the above referenced facilities to the same extent that the Facilit Plan estimate did. The costs associated with training facilities and handicapped accessibility would be included in the buildings modification cost estimates. These were generally not modified as most of the changes that we suggested involved tanks and equipment located outside of these buildings. The capability of the plant to pump the peak instantaneous flow of 5.19 MGD is also unchanged from what is referenced in the facility plan. The only peak instantaneous flow pumping required with the oxidation ditch are the raw sewage pumps, as the flow from that point on is by gravity. Our Project Architect will work with the City to determine handicapped accessibility and training requirements. 10. Describe the advantages and disadvantages of the low Interest loan program through the MPCA. The state revolving low interest loan program was discussed in section VII of our proposal. The major advantages and disadvantages of participating in this program are summarized below. Advantages 1. Below market interest rate based on a point system relative to user costs; 2. A fiscal consultant is not necessary; 3. Reduced bond counsel fee. PFA provides tax exempt opinion; 4. Longer term financing than most municipal bonds; 5. 18 to 24 month grace period before first payment and 6. Draw down of PFA funds after construction for engineering and construction. Disadvantages 1. Time and ant associated with administering the loan; 2. Construction costs may be increased due to having to comply with the Federal Labor Standards Provision; 3. Loan application documents are extensive and time consuming to prepare; and 4. Participation in the program required that a Facility Plan be prepared and approved. A Facility Plan is not required if other funding will be used. If a Facilities Plan is not pr -pared, we would recommend that an engineering report be prepared for NIT -CA review. Tl us is not absolutely necessary, however it does provide the opportunity to obtain MPCA comments before preparation of the plans and specifications. To obtain a PFA loan for either the facility planning or design, the City must be placed on the MPCA Project Priority List (PPL). Monticello Is currently not on the PPL, and should request placement as soon as possible if a state low interest loan is desired. 11. Does your proposal increase, lower or not affect the O & M costs projected In the Facilities Plant The O & M cost estimates in the Facilities Plan were not broken down into categories (e.g. power, manpower, chemicals, supplies), and the assumptions used to develop the estimates were not provided. This males it difficult to develop a meaningful comparison of additional alternatives. It is also difficult to develop a realistic independent cost estimate with the information available during the preparation of a proposal. We did develop an estimate of the O & M costs using the cost curves contained in the USEPA Innovative and Alternative Technology Assessment Manual (USEPA document No. 430/9.78009). The estimated O & M cost for the oxidation ditch facility with aerobic digesters was within the estimating accuracy of the costs projected for the recommended alternative. A more detailed comparison should be made using the same assumptions used in the Facilities Plan estimate. .J 12. Are there any incentive grant monies available from any other sources? There are incentive monies available for planning and studies however the amounts are small and the administrative procedures are cumbersome. Most of the grant programs are available to those communities that have a disproportionate percentage of low or moderate income households. Monticello basically doesn't quality for grant funding today. 13. Under your proposal, does a change order result in additional engineering fees? Our proposal was based on the assumption that compensation for engineering services be based on hourly rates, with a not to exceed limit. Change order evaluation and preparation is considered a normal contract administration task and a modification to the engineering agreement is not normally requested. A possible exception would be if the City requested a change that modified the original project scope and required a significant amount of redesign or additional design. Questions specific to SEH 1. At what cost would your estimate of the type of facility you are proposing given the design parameters from Table 212 of the Facilities Plan? In the proposal that was submitted, we indicated that we felt that an oxidation ditch activated sludge facility could offer significant advantages to the alternative that was recommended in the Facilities Plan, and should have been evaluated in greater detail. We are not proposing that this alternative be selected, but rather, it should be evaluated in greater detail, certainly beyond the evaluation done as part of the proposal preparation process. We have prepared a preliminary cost estimate for an oxidation ditch facility using aerobic digestion with the cost estimate for the recommended alternative in the Facilities Plan. This is summarized in the table below. It should be noted that the estimate in the Facilities Plan was based on a sated assumption that the electrical and mechanical construction casts were 10% and 7% of the of the remaining costs. The actual percentages were 8.5% and 5.8%. These same percentages were used to permit a comparison to the recommended alternative, though the electrical costs will likely be closer to 10-ISIA of the other costs. Estimated Conte T)escriplinn Facility Plan Oxidation Dit h Liquid Treatment Preliminary treatment $350,000 $350,000 Raw wastewater pumping 150,000 150= Primary clarifiers 700,000 220,000 Yard piping 190,000 190,000 Trickling filters 840,(10(1 0 Intermediate clarifier / pumping 60,000 0 Activated sludge 480,000 1,600,000 Final clarifiers 1,000,000 1,000,000 Sludge pumping facility 700,000 700,000 Disinfection 100,000 30,000 Demolition 30,000 30,000 Electrical 390,000 363000 Mechanical 270A00 248,000 Replace existing sludge pumps 90 70,000 Subtotal $5,350,000 $4,9SI M sludge Treatment DAF or thickening $390,000 $390,000 Sludge storage 1,440,000 740.000 Renovate covers 17044 170,000 Replace boiler, heater and gas controls 290,000 150,000 Pumps 270,000 270,000 Process piping 150,000 150,000 Blowers 0 30400 Diffuser system -0 100diM) Subtotal $2,710,000 $2,000,000 Total Estimated Construction Cost 5810601000 56,951,000 (ditches) IPA ,1 Based on the above estimate, it appears that the oxidation ditch alternative may be less costly than the recommended alternative. Z What additional work would need to be done for the Facilities Plan to be complete in your opinion? The work needed to complete the Facilities Plan and obtain approval from the MPGA is a function of whether the recommended alternative is the alternative desired by the City. We reviewed the MPCA Facilities Plan checklist to determine if the information they require was included and identified the following items that need to be accomplished before they will approve the document. A copy of this checklist is provided for your information. • Document must have an Engineer's certification and signature; • Confirmation of effluent limits should be obtained from MPCA; • City must hold a public hearing prior to adopting the Plan, • City council must adopt the Facilities Plan through a formal resolution; • A description of the potential environmental impacts must be provided along with a comparison to the other alternatives; • A treatment agreement for major industries should be included; • A Design Flow and Loading Determination Worksheet will be required; • An Environmental Information Worksheet should be completed; • Discussion of interim treatment during construction should be provided; If other alternatives are to be evaluated, the original Facility Plan should be completed as indicated above and certified by the consultant that prepared the Plan. An amendment should be submitted along with the original report covering the other alternatives and revising the recommendation, if necessary. A formal Facilities Plan is not required if the City chooses not to participate in the Revolving Loan Program. 3. Why would/wouldn't you consider using SBRs at Monticello? SEH is willing to consider any additional alternatives that the City would desire, including SBRs. It is important that the decision on the treatment proposed be based on a thorough analysis of the viable altematives, and not the cursory analysis performed as part of a proposal. During the preparation of our proposal, we felt that the oxidation ditch alternative deserved more consideration than was given in the Facility Plan. This process offers several advantages for this installation, including: • Easy to operate and control; • Minimizes interstage pumping; • Easily expandable to meet future needs; • Can meet future ammonia and phosphorus limits; • Sludge generation rates are less than other processes and sludge tends to be more stable; • Numerous similar installations throughout Minnesota; J • Cost effective to construct and operate; Sequencing batch reactors (SBRs) may offer some of these same advantages, however they do require fairly extensive electronic controls and do not have an extensive operating history in Minnesota. The installations are also generally smaller than the Monticello facility. An additional consideration with SERs is that the aeration occurs over a shorter period of time, which will increase electrical demand diarges. 4. Which process yields itself to better odor control (less costly and fewer problems)? Most odor producing compounds found in domestic wastewater and sludge result from anaerobic biological activity involving organic material, sulfur and nitrogen compounds. Some of this activity occurs in the collection system and will be a concern in the headworks facilities for all alternatives. The odors generated from the biological activity in the plant can be minimized by maintaining aerobic conditions to the extent passible, and covering and treating the air released from areas where anaerobic conditions exist. Odors resulting from secondary treatment facilities are generally related to areas of inadequate dissolved oxygen. This may result from shock organic loads that exceed the capabifity of the aeration equipment, accumulations of scum, inadequate mixing in the aeration tank, and sludge deposits. Trickling filters must contain uniform air circulation and wastewater distribution patterns to minimize odor generation. The oxidation ditch is a very forgiving process with respect to shock loads. The volume maintained under aeration is large and degree of dilution is high. Incoming shock organic loads are diluted and readily aerated. The oxidation ditch may have less potential for odors than an SBR because the aeration tank is continually aerated. An SBR tank is generally not aerated during a portion of the filling stage, which can last several hours. This would appear to increase the potential for odor generation during this time. We also indicated that aerobic digestion should be evaluated. the sludge obtained from an oxidation ditch is already partially stabilized and if the primary clarifier is eliminated, anaerobic digestion may not be cost effective. An additional advantage of aerobic digesters is that the potential for odors is significantly less. The digested sludge also has less potential for odor generation. Section 1 Introduction SEH Introduction The backbone of a design firm is, and will always be, its project managers. The approach to project management within industry-leading firms is oneof singular responsibility for the life of the project. Accomplished project managers are responsible for staffing and managing all aspects of the project. This includes the work effort of the project team and the work performed by all disciplines even though they may not be specifically trained in the technical aspects of other disciplines. The most important factors in this approach to project management are responsibility and accountability. The project manager is both responsible and accountable for all aspects of the project from initiation to closeout- The project manager is responsible for the quality of the product and the finandal profit or loss generated by the effort. Obviously it is of central importance to the success of the firm to develop highly skilled project managers. For these individuals serve as 'mini-pnindpals" of the firm and are responsible, at any given time, for all aspects of the business. Effective project managers create and maintain a work environment which fosters innovative, productivity and responsiveness to tate client's objectives for prorjects. To maintain competence and competitiveness, each project undertaken must represent a best effort by all involved and produce the high quality products which clients expect. SEH's statement "Quality Service Through Quality People places emphasis on quality. The reason for thb statement should be obvious; but may be overlooked in the daily routine of providing service. SEH project managers are effective leaders whoencourage people to achievehnovation and quality. The project manager is responsible for the successful outcome of a profitable quality project Purpose of Therefore, the purpose of this manual is twofold: Manual Its first purpose is to provide SEH project mangers with a convenient source of proven and effective techniques and approaches to project management. The second purpose is to assist project managers in gang a fuller understanding of effective project mmagement techniques and procedures by presenting them in a convenient activity -by -activity format. 11/11/94 SEH Projoct Management Manual i - f Standard procedures are necessary so that: 1. New project managers have a guide to follow as they learn how to carry out their responsibilities and maximize their effectiveness. 2. More experienced managers can have a reference to which they can tum when they are faced with problems which they have not encountered. I The firm can present a consistent face to its clients as it undertakes to plan and execute design projects. 4. Intra and interoffice coordination, communication and consistency can be enhanced. Adherence to the techniques described in this manual will neap SEH and project team many benefits: I. Highly successful projects, measured in terms of client satisfaction, high quality products, a sense of real accomplishment by all members of the project team and, of course, a profit. 2. A uniform format for efficient review of project performance. I An ability to transfer projects, when necessary, to a new project manager. 4. A capability to nue the experience and data of completed projects more efficiently and effectively in new projects. Manuals, procedures, organizational structures, systems and other management tools do not creatp high p=Jarmancw. Nor can this or any manual stop the thinking process. Continue thinking, effective leadership and motivation of people sets the standard for excellence in the finished project. This is created only through the talent, experience and dedication of staff. Using Manual This manual contains briefing sheets, checklists, sample formats and information of all types to support the project manager's efforts to do a thorough and complete job with a uniform format. J I • 2 SEH Pn*a Managoment Manuel 11/11184 We must also recognize that projects undertaken by SEH are diverse in size and scope — ranging from small studies to large design and construction management service efforts, with a wide variety of services provided and skills required. This Project Management Manual is not and cannot be a substitute for good judgment. It is not intended to include all procedures and situations that can be foreseen. Exceptions will occur and ought to be anticipated. The overall philosophy of this manual is to provide proven techniques which are to be supplemented by good and sound judgement on the part of the project manager. Once in place, the manual should not be treated as a static document. It must grow and evolve as it becomes adapted to the specific requirements and circumstances, As you work with the manual, discuss questions and suggestions for improvements with your supervisor and principals. Suggest revisions to be made so that SEH can amend and update the manual regularly. Caution! Use of thir`Projed.Managemerrt Manual- is eat intended to establish or create a legal staedard•of conduct or dirty toward the public on!!tbepmt of SEH. Sne standard and.duty of rare is'imtended to - remain that standard which has been established .by statutory .law .and judicial -determinations-... tofthin thefnduetsy. 27ne information eontafned-in ;.., thln%maiival'ia intended sokly for the purpose of 'itrformasion and guidance to the -staff -ami _ snmragaureet.of.SEH. As with my guideline, the trehrdgisee. presented In -His mwnual .should - be _c;appfied,eanfuUyandrhouW.betnodifiedtofrttht- . . particvlartitvation. In each instance, where it is determined that the standard of care in the industry is greater than that appearing to be indicated in this manual, it must of course, be the policy of SEH that the standard of care m the industry be practiced. Forms and checklists are provided throughout this manual. However, they are not intended to be either exclusive or all encompassing, Such forms and checklists are merely a guideline to be tempered with professional judgment. 11/11184 SEH Projoct Managomont Manual f - 3 HOW Manual This manual was developed by personalizing the PSMJ Was Developed Project Managers Manual to meet SEH needs. SEH Senior Project Managers and Department Heads are always available to assist any pry manager resolve project management issues. •They,are available by phone to help you, the project manager, understand the documents and tools in this manual or to assist in any other aspect of project management. I • 4 SEH ProJac7 Management Manual 11/11194 June8, 1995 11 red Circle drive . 130 mn ictonka, monesaur 55343 812.935.6901 tax 612.935.8814 Mr. John Simola Public Works Director City of Monticello 750 Fast Broadway P.O. Box 1147 Monticello, Minnesota 55362-9245 Re: Responses to Additional Ouestions DearJohn: Enclosed for your review are RCM's responses to the additional questions presented to us regarding our proposal for engineering services for the City's wastewater urroU rtMNer treatment plant expansion. We understand that the City Council intends to select an 111110datim hv- engineering firm for the project during their workshop to be held at &W p.m. next Monday evening. J surveyors We sincerely behove that our tram is the best choice to work with the City on this MW apporrwury important project. We thank you again for being considered for this project and look empaoyer forward to the opportunity to continue to work with you, Sincerely, RF EKE CARROLLMULLER ASSOCIATES, INC Saco 4 Clamsen, P.E Vice President SI.Oaec Attachment c: Ed DeLaForest, OSM 11 red Circle drive . 130 mn ictonka, monesaur 55343 812.935.6901 tax 612.935.8814 Monticello, Minnesota Rieke Carroll Muller Associates, Inc. (RCM) Responses to Questions Wastewater Treatment Plant Design Consultants Now would changes to the p gjed be documenW to ensum quality as•buift "? During construction of a wastewater treatment project, changes to the design plans and specifications may be required These changes are documented during construction and transferred to a set of plans which are identified "as -built" plans or "record drawings". The changes are documented as follows: a. A "change order" or "field order" which describes a change is prepared. This change order or field order describes the change in "narrative form". Changes are then entered on the construction pians to identify dimensions, locations, etc. b. Not all changes are "change orders" and do not require formal processing. These may include such items as different connection details, different valve locations, different depths, etc. In such cases, the contractor prepares a sketch of changes to indicate locations, dimension lines, etc. The RCM resident project representative also prepares a sketch of the changes and marks those changes on a "field set" of the plans. At the completion of construction, the RCM project engineer and draftsperson transfer the information to a "record" set of the drawings and reviews the changes with the City. After reviewing changes with the laity, final changes are made and a file copy of the record drawing is submitted and filed. RCM Page 1 City of Monticello 2. Can pow firm be sure to fnc/ude facility plan taus in PFA apprs.? J Yes. Facility planning costs, design costs, and construction costs are all eligible costs that can be included in a PFA loan. All of the costs can be rolled into the PFA Loan at the time of construction to expedite project completion_ We have successfully used this approach on projects for other cities. 3. Doer paar firm provide written reporting of pmled prngreo on a repdar (weekly • monthly) basis from pons and specs througheonabudion? Yes, RCM provides written reports to whatever degree is desired by the client RCM firmJy believes that good communications result Jim good projects. Good communications and coordination with the City staff will be critical elements for the success of the wastewater treatment plant project. To assure good communications and coordination with the City staff, we propose to submit written monthly project progress report, to have monthly project progress review meetings with the City staff, and to make weekly verbal project progress reports to the City staff. We will also communicate on an "as -needed" basis as issues arise that need timely discussion. there will be critical times during the project, particularly during construction, where daily communications will be necessary. We will use written memos to document verbal communications and during construction RCM's resident project representative will keep a daily log of the construction activities. 4. Doesyow f rm ust a project management manual? jjso, Bayou provide such a document to dknts? Meat is typical of its content? RCM uses project manager guidelines and each project manager is responsible to develop a project management manual for the projects they are responsible for. IMe project management manual includes project schedules, monitoring of the project progress in comparison to the project schedule, agendas and minutes of meetings held intemallywith the project design team and meetings held externally with the owner. "mini" drawings, project specifications outline, designldrafting standards, soils reports, NPDFS permit, critical correspondence with regulatory 6l RCM Page 2 City of Monticello I agencies, critical correspondence with the owner, and the agreement between the owner and RCM. In addition to the project management manual, our construction services engineer keeps a manual during construction that includes the construction contract, change orders, field orders, progress payment applications, the construction schedule, a log of shop drawings, materials testing results, construction deficiency notices/resolutions, punch lists, substantial completion certificate, final completion certificate, and all critical correspondence with the Owner, contractor, regulatory agencies, and permitting authorities. As mentioned previously in No. 3 above, RCM's resident project representative keeps a daily log of construction activities. 5. At what point in tient dues yourJfrm propose to involve MPCA and to what degm? RCM proposes to contact the MPCA immediately upon being retained by Monticello. The reason for early contact is to get the City on the MPCA Project Priority list for loan funding, to assure that loan eligibility is retained, and to verify that no recent or proposed changes to the regulations will affect the proposed plan. Typical involvement with the MPCA during the project includes the following: a. Submittal of facility plan and presentation of same to staff. b. Respond to MPCA questions on the facility plan. C. Notify MPCA of initiation of design d. Submit preliminary design narrative to MPCA and review with staff. C. Submit preliminary design and plans to MPCA and review with staff. f. Submit final design plans and specifications to MPCA and review with staff, g. Respond to MPCA comments. h. Send copy of bid set of construction plans and specifications to MPCA at the time of bid. i. Send M PCA copies of addenda. j. Notify MPCA of bid results. It. Send copy of contractor's Notice of Award to MPCA. I. Send copy of contractor's Notice to Proceed in. Submit copies of change orders to MPCA. n. Schedule site visits by MPCA staff. RCM Page 3 City of Monticello o. Submit PFA pay requests to WCA. p. Notify MPCA ofsubstantial completion inspection. q. Notify MPCA of final inspection. r. Submit 0&M manual to MPCA for review. S. Respond to MPCA comments on O&M manual t. Receive approved O&M manual from MPCA and file with proper City officials. U. Submit record drawings to MPGA in required format. 6. /s dwri a betty time of year ja the moat conspetitive bidr on the prq=4 and what impact on rhe bids would Jnar p -posed Amount have, ifany' The best time of year for the most competitive bids on a project is when contractors are looldng to fill their work schedule. Usually, this means that it is best to advertise a project in the early winter months, December or January, with bids being received in Februaryand issuing a Notice of Award in March. This schedule would allow construction to begin in April. The schedule which RCM proposed will take advantage of bidding the project at the most opportune time. This should mean the most competitive/lowest bids for the City of Monticello. 7. Tothosn-ho prepaced—nlrgtoehm6wepdmaryciarjj7err,pfeasediret quandliesamktpamd of semnfngr and how final dispud might be areompUshed "Coarse" screens and "fine" screens are discussed in the facilities plan. A "preliminary" coarse screen facility in the influent room of the control building is proposed in some of the options, including the recommended option. 116 screen would have 1/4 -inch openings. Approximately 10 cubic feet screenings per million gallons of flow would be generated. For disposal, the screenings would be "limed" and removed to a lined sanitary landfill. The "primary" screening discussed in the facility plan is a fine screen. This screen would be a static screen and would have screen openings of 0.060 inches. This primary screen would remove solids such asvegetable residue, cgg shells, and other material larger than 0.060 inches. The final screenings would be dewatercd, 'limed", and disposed of in the sanitary landfill. RCM Page 4 City of Monticello The primary screens fulfill the same function as the primary clarifiers; however, they are not as efficient. Approximately 30 cubic feet screenings per million gallons flow are typically removed. The facility plan did not propose to utilize a fine screen for either the upgraded existing facility or the activated sludge process; however, RCM has successfully designed primary screening facilities for several wastewater treatment plants. During recent years, solid waste regulations require that wastewater screenings may not contain free water. For that reason, some type of dewatering mechanism may be required for either the coarse screen or fine screens. This could consist of a screenings compactor located at the discharge of the screen. 8. AtsumbV future mttriew limits are enacted for llfondceflo and that they too will be high and variably loaded to flee faclGry, haw easily is your proposed system mad flea to aernmmodat It ear for nutnens amity? The nutrients which would probably be limited by the MPCA are ammonia and phosphorus. Ammonia can be removed to a concentration of 1 mg/I in a property designed trickling filter/activated sludge facility or activated sludge facility; this process is called nitrification. Any of the alternatives described in the facility plan can be designed to accomplish nitrification. Phosphorus can be removed biologically or chemically. The choice of the phosphorus removal method is dependent on the effluent standard. Typically chemical phosphorus removal is included as backup for biological phosphorus removal when the effluent standard is low. Any of the alternatives described in the facilities plan can be designed to accomplish biological or chemical phosphorus removal. It should be remembered that if nutrient removal is required, greater sludge quantities will be produced. Ibis means that the size of the sludge handling facilities will have to be increased and the cost of solids handling will also increase. RCM Page 5 City of Monticello 9. Does your estimated project clog or savingss ht& de apansi- of operatfoas and paining spasm, handicapped accen ihty Acre required, reasonable odor eontrn4 and a pbnt that can take a peak instantaneous wet wmOuiJiow of S. MGD (as per the FacWdes Plan) 7 The Facility Plan does not include the cost of an operations and training facility, however, such facilities are often constructed at wastewater treatment plants. RCM has designed numerous such facilities and one can readily be added to the project at a very nominal cost. The handicapped accessibility issue is a matter of building code constraints. Our facility design will meet the handicapped accessibility requirements. Our proposal includes a major effort for odor control. The alternatives in the facility plan are all sized to handle the peak instantaneous Flow of 5.19 mgd. 10. Describe the advaruages anddlsad uwm of du low Lrtrrest ban program through do MPC4. The primary advantages are: a. The City will receive a lower interest rate than is available on the open market. Out experience indicates approximately a 2 percent advantage through the loan program. b. The City does not need to sell bonds for the improvements, and therefore eliminates bonding costs. C. The City can request funds monthly to pay expenses as they occur. This eliminates interest costs during construction. d. The fust ban payment is not due until either two (2) years after the award of the loan or one (1) year after completion of construction —whichever is first. C. The bar. does not affect the City's legal bonding limit. RCM Paso 6 Crary of Monilocuo The disadvantages are: a. Federal regulations apply to this project which includes assuring compliance with the Davis Bacon wage rates, and other federal regulations. Consequently, construction cost may be greater. It is our experience that the financial advantages of the loan program outweigh the disadvantages. 11. Doeryouo proposal increase, town, or not affect O&M cosxr prgjeued In the Padhtles Plan? During the facility planning process, the oxidation ditch process was evaluated and was dropped from final consideration, based upon anticipated high construction cost. Consequently, the trickling filter/activated sludge alternative was recommended. During the interview, RCM was asked if an oxidation ditch would be a viable alternative to the trickling filter/activated sludge process. In response to this question, RCM further scrutinized the oxidation ditch process and prepared a revised cost estimate for an oxidation ditch facility at the existing site. The attached memo entitled "Revised Oxidation Ditch Alternative", dated May 31, 1995, sununarizes the alternative. The construction cost of an oxidation ditch would be about I1 percent less than the trickling filter/activated sludge alternative. The O&M cost of an oxidation ditch facility may be about 15 percent more than the selected alternative, depending upon the manner in which the City processes sludge. Attached Tables I and 2 show comparisons of the trickling filter/activated sludge process to the oxidation ditch process. Although it is expected to have a greater operation cost, an oxidation ditch provides several nontronomic benefits over the trickling filter/activated sludge process. These include simpler operation, greater ease of expansion, fewer pumps, and less potential for odor. RCM Page 7 City of Monticello 12. Aro then any hemi iw grant monies arwilable from any adrr sounarsl J Potential funding sources in addition to the Minnesota Public Facilities Authority (PFA) are as follows: • Minnesota Department of Trade and Economic Development. ■ U.S. Department of Commerce/Economic Development. • Rural Economic and Community Development (previously FmHA). ■ Special legislation grant funding. The Minnesota and U.S. governments will consider issuing Economic Development grants if the project will result in furthering the economic base in the community (such as encouraging industrial growth). The Rural Economic and Community Development funds focus primarily on low income situations. The area of the Mississippi River which receives Monticello's effluent has been designated on Outstanding Resource Value River, which accounts for the stringent effluent standards. It does not seem reasonable to require the City of Monticello to pay for excessive treatment when society benefits as awhole. For that reason, Monticello could pursue special legislation for additional state or federal funding of the treatment plant. Assistance from local legislators would be very helpful. 13. Under your proposal, dars a change order result in additional engineering fees! No. Glue only exceptions are if the City requests a change order that is a major design change or if the project construction experiences o significant delay.) K RCM Page 8 City of Monticello Table l Estimated Construction Cost Monticello WWTF (1) Per Table 8.7 of Facilities Pian. (2) Per Table 1 of Revised Oxidation Ditch Alternative. RCI Pap 9 Ciry of Monticello Uoarade Existing Plant(') Oxidation Ditch(2) 1. Preliminary Treatment $350,000 5330,000 2. Raw Pumping 150,000 150,000 3. Primary Clarifiers 700,000 4 4. Yard Piping 190,000 210,000 5. Trickling Filter 840,000 4 6. Oxidation Ditch 4 2,400,000 7. Activated Sludge 480,000 4)- 8. Intermediate Clarifier 60,000 4)- 9. Final Clarifier 1,700,000 1,700,000 10. Disinfection 100,000 100,000 11. Demolition 30,000 80,000 12. Replace Pumps/Blowers 90,000 4 13. Odor Control 1,400,000 500,000 14. Electrical 390,000 500,000 15. Mechanical 270,000 300,000 16. Sludge Handling 1,990,000 1,600,000 17. Interim Improvements 110,900 Subtotal $8,850,900 $7,870,000 13. Contingencies (15%) $1,329,100 $1,180,000 14. Engineering Legal Administration S1,770M 1370AM (2017o) Total: 511,950,000 510,620,000 (1) Per Table 8.7 of Facilities Pian. (2) Per Table 1 of Revised Oxidation Ditch Alternative. RCI Pap 9 Ciry of Monticello Tabic 2 Estimated Operation and Maintenance Costs Monttceuo v m Upuade Fxdsliny Plane') OAdation Ditchnl 1. Labor and Benefits $280,0010 $280,000 2. Electricity 65,000 104,000 3. Other Utilities 14,000 11,000 4. Chemicals 34,000 79,000 5. Materials and Supplies 68,000 68,000 6. Testing 11,000 11,000 7. Professional Development/Training 4,000 4,000 8. Insurance 12,000 12,000 9. Support Services 11M Is,ggQ Total: $503,000 $584,000 (1) Per Table 83 of Facilities Plan. (2) Per Table 4 Revised Oadation Ditch Alternative, RCM Page 10 laity of Monticello IJ R Pkase discuss interim drahnent to matntatn the permit daring conshuction of your proposed ptaat. The flow control gates in the existing channels in the influent room will direct the flow directly into the wet well so the preliminary screening facilities may be constructed. The only inconvenience this would cause is that a manually cleaned bar screen will be needed to remove the screenings during this portion of the construction. Grit Removal. The flow control gates, which will be used to divert the flow during installation of the preliminary screening facility, will also be used to control the flow during reconstruction of the grit removal facility. Wastewater bypassing will not be a major concern. Raw Wastewater Pumps. The plant currently has four raw wastewater pumps. The intention is to convert the pumps to be capable of handling increased flows. We intend to utilize existing piping and remove one pump at a time so adequate pumping capacity would be maintained at all times. Under peak instantaneous flow conditions, the existing pump suction lines would experience velocities in excess of 12 feet/second, which could cause cavitation. For that reason, a large capacity stormwater pump will be installed in the wet well. In order to perform construction operations in the wet well, the now must be excluded for a short period of time. We intend to utilize the grit basin as a temporary wet well during installation of the stormwater pump. A temporary submersible pump will be installed in this temporary wet well and will connect to the new discharge piping for the stormwater pump. Primary Clarifier. The manner in which the primary clarifier would be constructed depends upon where it will be located. If it is located in the arca shown in the facility plan, then no bypassing or flow diversion will be required because the clarifier will not be impacted by the operation of the existing plant. RCM Page 11 City of Monticello If the primary clarifier is constructed in the vicinity of the existing primary clarifier, then a temporary connection will be made between the diverter discharge pipe and the trickling filter influent line. A temporary static screen will be installed at the diversion structure so all the pumped wastewater will receive screening prior to flowing through the trickling filter. Trickling Fiher. At the same time the primary clarifier is being constructed, the two new trickling filters and the flow splitter structure will be built. Upon completion of construction of the new trickling filters and clarifiers, the wastewater will be directed into the primary clarifier and allowed to flow to the two new trickling filters. The wastewater will flow out of the two new trickling filters to the intermediate clarifier and the intermediate pump station for subsequent pumping to the activated sludge tanks. Once the new trickling filters are placed into service, the esisting trickling filters will be refurbished. Ac huW Sludge. The two new activated sludge basins will be constructed at the same time the two new trickling filters are constntcted. When completed the flow will be diverted into the two new activated sludge basics and the two existing activated sludge tanks will be rehabilitated. 0 Final Clarifiers. no two new final clarifiers and the sludge pumping facilities will be constructed at the same time as the new trickling filters and aeration basins. Once the new pumping facilities and clarifiers are completed, the entire trickling fdter/aeration basinifinal clarifier complex will be plaited into service at the same time. Disinfection. The chlorine contact tank will be approximately doubled in size and will be constructed next to the existing chlorine contact tank. The "connection" to the new chlorine contact tankwill be done during winter months when disinfection is not required. In summary, during the entire construction process, treatment capacity no less than that which currently mins. no plant should have no difficulty in maintaining permit limits during construction, RCIM Page 12 City of Monticello 2. Discuss in mon detail why you Jed SBRs or oxidation &chn are nd good options for the City of Monticello. Pkase provide a list of ODS and SBR's your firm has built. Following is a list of oxidation ditches and sequencing batch reactors (SBRs) which RCM has designed. year C& Tyne of Facility 1975 Winthrop Oxidation Ditch (industrial Plant 1983 Lester Prairie Oxidation Ditch 1986 Winsted Oxidation Ditch 1987 Blooming Prairie SBR 1987 Holdingford Oxidation Ditch 1989 Randall SBR 1990 Mora Oxidation Ditch 1990 Rogers Oxidation Ditch 1995 Pine River Sanitary District Oxidation Ditch RCM has designed more oxidation ditches and SBRs than any other firm In Minnesota and we believe that both SBRs and oxidation ditches are good treatment options for the correct situation. The reasons these two treatment processes were not selected as the recommended alternatives in the facility plan are discussed below: FIAT Monticello's future wastewater standards will require that the mass loading to the Mississippi River does not increase beyond current amounts. Thus. the process must be capable of producing an effluent BOD and suspended solids of approximately 10 m&4. In addition. the plant must be designed so it may be easily modified to achieve nitrification and phosphorus removal. We are concerned that RCM Page 13 City of Monticello there is very little operational data available to indicate that an SBR facility can meet the possible future effluent limits for Monticello. 'Me majority of the SBRs built in the United States have been for facilities smaller and more lightly loaded than Monticello. Project lists provided by the two major SBR manufacturers (TransEnviro, and Austjen Bio.let).identify that the average design flow for SBRs is under 0.5 mgd. This compares with Monticello's average wet weather flow of 1.98 mgd. RCM has designed SBRs in Blooming Prairie and Randall, Minnesota Blooming Prairie, Minnesota presents an interesting case because an industry within the City also utilizes an SBR as a pretreatment process. 'This industry produces a high- strength organic waste and they have experienced that the industrial plant SBR has had difficulty, inconsistently meeting their pretreatment standards. (RCM did = design the industrial SBR.) Based on comments presented at the interview, RCM is preparing a cost estimate for an SBR. We have requested SBR equipment costs from the manufacturers, but have not yet received them. For that reason, we propose to present the complete cost of the SBR plant in the facility plan "tune-up" which we previously proposed. RCM did investigate the feasibility of oxidation ditches during the Monticello wastewater facility planning process for three different scenarios. Oxidation ditches were investigated as the sole biological treatment at the plant, as a remote "B" plant, and a complete plant at a remote site. faring reviews of the preliminary alternatives with City uaff, it was decided to drop consideration of the oxidation ditch at the plant due to its cost estimate being greater than the other options. Based on comments at the interview, we have revisited the feasibility of RCM Page 14 City of Monticello constructing an oxidation ditch at the existing plant site. The attached memorandum discusses the anticipated construction, operation and maintenance, and life cycle costs for an oxidation ditch plant at the existing site. This cost estimate was done in a way to closely scrutinize individual treatment processes and be consistent with the cost estimates in the facility plan. The revised estimate shows that an oxidation ditch can be designed to cost less to construct than the other alternatives; however, the life cycle cost is anticipated to be greater than the other alternatives. RCM believes that issues other than cost alone should be considered when implementing any treatment process. An oxidation ditch on the existing plant site would provide some values which other processes do not. These include: • Easier operation, since only one biological treatment process (oxidation ditch) would be used rather than two (trickling filter/activated sludge). • An oxidation process would allow the City to abandon the use of approximately 15 pumps. • Cidorcontrolwould be easier to accomplish with an oxidation ditch than with the trickling filter/activated sludge because the sludge from an oxidation process would be aerobically digested rather than anaerobically digested. The aerobically digested sludge may not meet the EPA 503 sludge regulation, however. Further treatment of the sludge via heating, composting, or lime treatment may be necessary. • An oxidation ditch would be easier to expand in the future (after year 2020). The next expansion of Alternative 1 would be more difficult to accomplish and more difficult to operate. RCM Page 15 City of Monticello In summary, RCM believes that the oxidation ditch process is a viable treatment alternative. If the cost of the facility is not an overriding concern to % the City, then the City may wish to explore it further during the facility plan "tune up". 3. You indicated }row firm would take another Took at doss A"sh dp Aside from a joiru reatum with &COhlo avtra-poreation to du Wnght Conary compost fadk, what option woould)ou study further? The options available for producing a class "A" sludge are: lime treatment, heat drying, heat treatment, autothermal thermophilic aerobic digestion (ATAD), and aerobic thermophilic pretreatment (ATP). Currently, litre treatment is most commonly used for sludge treatment. lime treatment has one inherent problem, however. A limit exists to the amount of treated sludge which may be applied to the disposal site because the soil pH will eventually become elevated to unacceptable levels. ATAD amounts to performing aerobic digestion with auxiliary heat added. This will require an external fuel source because sufficient methane gas would not be present for the process. ATP is a pretreatment stage ahead of anaerobic digestion. It operates at 55 to 66°C and is generally a pasteurization process. Ignited volatile suspended solids (VSS) digestion occurs in the process and therefore an anaerobic digestion system is needed to complete the treatment step. We propose to investigate each of these tltematives in the facility plan "tune-up" and present costs for each alternative to the City. 4. Pagr 1.1 of you proposal sed a goal a 1%-eM1nry,"'b faetll y that wUl car product g8eart ve odors. " is this malty wilhte yow control as As dalgn eaglaen, and what guartanur would you give the comawafry and at khat cast! By "certainty" in our proposal, we meant a wastewater treatment facility that will work — It will be properly designed to meet effluent limits and not produce offensive odor. We have achieved these results on numerous projects in Minnesota, but you are right in your assumption RCM Psgc 16 CiryolMonticeuo that these results are not totally within our control. The facility will be designed to treat the projected flows and loads. If those flows or loads are greatly exceeded for some unforeseen reason, such as an industrial spill, the facility may not be able to perform as designed. We also have to assume that the facility will continue to be property operated. Odors are a particular problem for wastewater treatment facilities. Some people are convinced that odors are present by the mere fact that a facility treats wastewater. In fact, no wastewater treatment facilities are odorless. That is true for almost all businesses and industries — gas stations, restaurants, manufacturing facilities, food processing plants, etc. all have odors. The keys to designing a wastewater treatment facility so that it does not produce offensive or significant odors are 1) keep the wastewater aerobic or fresh, 2) contain potential problem areas within the facility, and 3) treat the air from these areas to "scrub" the odors. RCM does carry errors and omissions insurance that provides coverage to our clients if we make a mistake that damages our client. 'there is a catch — if we, or any other engineering fum, "guarantee" the work product, the errors and omissions insurance becomes null and void. We dg stand behind our work but if we "guarantee" our work, our insurance does not stand behind us. If the City desires additional protection, the City/RCM could take out a project specific insurance policy or possibly a performance bond. There would be additional cost for either of these. We have not been required to provide project specific insurance or a performance bond on any project to date, but both are available if desired by Monticello. S. Does your firm still befiety the bat option for the City is apansiou of tla existing facility with adimied shulp and tricMit1 fihers when c+oerlEtting conaludlon cost, OAA! cost, Jiuun npandon cost, dwelt load capabilities, and cHiknt odor eonWP RCM believes that expansion of the existing facility with activated sludge and trickling filter will produce the lowest life cycle cost facility. Furthermore, RCM believes that this process lends itsclf wcll to phased construction. RCM Pagc 17 City of Monticello When factors other than cost are considered, the trickling filter/activated sludge process may 1 be less desirable than an oridat_ion ditch at the existing site. "Riese factors include: ■ A trickling filter/activated sludge facility will be more difficult to operate than an oxidation ditch facility. ■ Odor control processes must be carefully managed for the trickling filter/activated sludge. Both the air handling systems and the scrubbers require diligent operation. 'IAe potential for odor from the oxidation ditch process will be less than the activated sludge/trickling filter process, due to the fact that all treatment processes are aerobic. ■ A new oxidation ditch facility can be laid out for efficient expansion after the design life of this project has expired, i.e. 2020. Conch, n: As a first step of the wastewater improvement project, RCM recommends that the City proceed with a facility plan "tune-up" where each of the issues raised may be evaluated and disassed with the staff in a comprehensive manner. 'Ibis will allow the selection of a final plan which will be both cost-effective and user friendly. r RCM Pago IS City of Monticcllo MEMO REVISED OXIDATION DITCH ALTERNATIVE MONTICELLO, MINNESOTA May 31,1995 History On September 9, 1994, Larry Anderson sent a memo to John Peterson (OSM) discussing four treatment alternatives (attached). This included an oxidation ditch at the existing plant site, and also included a preliminary layout of the oxidation ditch facility on the existing plant site. On September 20, 1994, Sam Qaassen, Larry Anderson, and OSM staff met with City staff to discuss options (see attached agenda). At this meeting, it was decided to drop the oxidation ditch alternative at the plant site, but to consider it as a "B" plant to be utilized in parallel with the existing plant. This "B" plant became Alternative 4 in the Facilities Plan. Undated OxidatloApitch Evaluation In May 1995, RCM re-evaluated use of an oxidation ditch on the existing plant site and prepared the attached revised cost estimates. In this re-evaluation, the following changes are made to the September 1994 facility. CnDital Cost Esilmnteq 1. Preliminary Trentment - The September 1994 proposal did not include new preliminary treatment equipment in the existing control building. Rather, the intention was to pump all the wastewater, inchtding the grit and screenings, to a new primary screening facility located near the Flow divener building. An altemate to the previous plan would be to construct the preliminary treatment equipment in the existing influent room of the control building as discussed in Alternatives 1, 2, and 3. Some further cost savings would be possible by utilizing a coarse screen similar RCM Page i City of Monticello to a lakeside Rotomat rather than the previously identified fine Parkson screen. The Rotomat screen would allow a greater amount of screenings and rags to flow to the / oxidation ditch, but this would not cause as great a problem in an oxidation ditch as in a trickling filter. By using a Rotornat, an estimated savings of about 520,000 would be expected from the previously identii ied preliminary treatment facility cost on Table 1. 2. Raw Wastewater Pamoinq - No changes to the raw wastewater pumping cost would be anticipated from that previously identified. 3. Primacy Screening• Since oxidation ditch facilities typically do not include primary clarification, the previous oxidation ditch alternative included a grit removal and static screen installation at a cost of approximately 5850,000. This $850,000 cost can be eliminated by eliminating the entire screening and grit facility. Greater amounts of solids and grit will accumulate in the oxidation ditch than if the screening facilities are installed. 4. Ynrd Plnine Wastenter - No changes would he expected. 5. OxMatbn Oltch - Based on the revised layout, the anticipated cost to construct an oxidation ditch is $2,400,000. Lakeside recommends two 14 feet deep ditches constructed in either a straight or a serpentine configuration rather than the four ditches discussed in September 1994. This would eliminate the feasibility of phasing the project; however, it could reduce some of the previous cost estimates by maximizing the rotor efficiency. If the City decides on an oxidation ditch facility, we can also use three or four oxidation ditches to allow the project to be phased. We had previously considered the feasibility of constructing straight oxidation ditches; however, based on the understanding that the 100 -year flood elevation is approximately 906 MSI. we stated that the ditches must be constructed at a higher elevation on the site. This would cause the ditches to encroach on the steep slopes of the site. New information indicates that the 100 -year flood elevation is approximately 902 MSL This would greatly impact the possible site layout. RCM Page ii City of Monticello If an oxidation ditch is to be implemented, a final decision will need to be made on the best location and configuration of the ditches. This should be based on an accurate site survey to establish an outline of the flood zone and to determine the amount of excavation and whether an earth retaining wall will be necessary. 6. Final Clarifiera - The previous cost of $2,400,000 was for four 40 -foot diameter clarifiers and a sludge pumping building. The sludge pumping building and facilities include waste activated sludge pumps, return activated sludge pumps, scum pumps, sludge piping and valves, sludge meters, and a 40 -foot by 50 -foot building housing the facilities. For the revised cost estimate, four clarifiers would not be required if only two ditches are constructed. The cost of two clarifiers was previously estimated to be approximately $1.7 million. 7. Disinfecrlon - In both of the alternatives investigated in detail (Alternatives I and 3), the existing disinfection facilities were determined to be adequate to meet current need, but the chlorine contact basins must be increased in size for future needs. B. Ormiitlgp -The September 1994 estimate included $30,000 for demolition. This cost was merely to remove the remnants of an old digester which exists in the courtyard between the trickling filter activated sludge digester complex This demolition would not be necessary if we do not construct a screening facility there. If the City should implement an oxidation ditch plant, the existing trickling filters, primary clarifiers, and equipment from the sludge handling facilities would not be needed. The cost of demolishing them would be closer to $80,000. 9. Odor Control - The September 1994 estimate Included a cost of $1.4 million for odor control for all options. The major odor sources were the trickling filter, anaerobic digester complex, and the influent pump station, If the anaerobic digester is replaced with an aerobic digester, the cost of odor control for the plant would be significantly less. RCM Page iii City of Monticello 10 & 1 1. Electrical and Mechanical - Cost estimates in the facilities planning reports set the electrical cost at 10 percent and mechanical cost at 7 percent of the remaining plant. Utilizing these percentages, the revised electrical and mechanical costs are identified in the attached table. 12 Sludge - The previous estimate included significant changes to the anaerobic digestion process, as well as additional sludge storage. Anaerobic digestion was included in all options based on the need to produce a sludge which would meet the EPA 503 regulations. Aerobic digestion cannot be relied upon to meet the 503 regulations. It must be further treated by heating, lime, or composting. An oxidation ditch produces a stable sludge and insufficient gas volumes may be available to heat an anaerobic digester. For that reason, aerobic digestion often follows the oxidation ditch process. The aerobic digester would have 20 days detention time, followed by 180 days of sludge holding. Assuming 0.75 pound of volatile solids is produced per pound BOD removed, 3,900 pounds of volatile solids will be generated per day. At 0.75 percent solids in the waste activated sludge, a digester volume of 1.25 million gallons is required. If sludge is thickened to 5 percent, then 187,000 gallons of digestion is required. 'Ilse two existing activated sludge basins each have a volume of 167,000 gallons. These basins can be convened into aerobic digesters with adequate volume. Aerobic digestion may achieve up to 40 percent volatile solids reduction, which leaves 2,340 Ibs/day volatile solids following digestion. By adding 1,020 lbs/day of fixed solids which are anticipated in the raw wastewater to the digested solids, the daily amount of solids requiring storage is 3,360 lbs/day. At 5 percent solids and 180 days storage, the total sludge storage requirement is 1,450,000 gallons. The existing digesters contain 1,000,000pllons storage. Additional sludge storage volume of 450.000 gallons is required. An aerobically digested sludge cannot consistently comply with the 503 sludge regulations for a Class B sludge. Additional treatment would be necessary for pathogen reduction. Lime stabilization is one possibility. Approximately 1 pound of lime is required for every 2 pounds of solids treated. Thus, approximately 371 tons of litre will be needed per year to treat the sludge. Thc lime may be added before the sludge is placed into storage or RCM Page iv City of Monticcllo when the sludge is drawn from the storage tank just prior to applying it to farmland. In the ` former case, additional storage is required; in the latter case, a larger lime feed system is required. A decision of which is more cost effective should be made after further investigation is done. Table 1 summarizes the anticipated construction cost'of an oxidation ditch facility if developed in the manner discussed above. Comparing Table 1 to the recommended Alternative 1 of the Facility Plan, an oxidation ditch has an 11 percent lower capital cost. To make a complete analysis, however, the facility salvage values, equipment replacement cost, and operation and maintenance cost, as well as the suitability for phasing, must all be considered. Table I Oxidation Ditch Monticello Wastewater Treatment Facility 1. Preliminary Treatment .................................................... $330,000 2. Raw Pumping............................................................150,000 3. Primary Screening ............................................................. .0- 4. Yard Piping.............................................................. 210,000 5. Oxidation Ditch......................................................... 2,400,000 6. Final Clarifier.......................................................... 1,700,000 7. Disinfection.............................................................. 100.000 8. Demolition................................................................ 80,000 9. Odor Control.............................................................500.000 10. Electrical................................................................500,000 11. Mechanical.............................................................. 300,000 12. Sludge Handling........................................................ IAMAQ Subtotal .................................. S7,870,000 13. Contingencies (15%) ................................................... S1,180,000 14. Engineering Legal Administration (20%) ................................... S1.570AM TOTAL ................................. $10.620,000 RCM Page v City of Monticello $alvaee Value Salvage values are calculated by depreciating a given item over its useful life on a straight-line basis, and then determining the remaining non -depreciated amount at the end of the planning period. The estimated present worth of the salvage values are summarized in Table 2. Useful life assumptions for determining salvage values as outlined by EPA are: • Land - permanent ■ Piping - 40 ye an ■ Concrete and earthen structures - 40 years • Process equipment - 20 years • Auxiliary equipment -10 years • Pumps -15 years Table 2 Estimated Salvage Values • Oxidation Ditch Montkdlo Wastewater Treatment Facility 1. Preliminary Treatment ................................... . .... . ............ $25,000 2. Raw Wastewater Pumping .. ................................................. 13,000 _ 3. Yard Piping (wastewater).................................................... 25,000 4. Oxidation Ditches ........................................... . ............. 280,000 5. Final Clarifiers............................................................116,000 6. Digestion.................................................................... 4 7. Sludge Holding............................................................ 4," 8. Sludge Pumping Facility ..................................................... 65,000 9. Disinfection............................................................... 10,000 TOTAL .................................... $582,000 Eaulmnent Replacement Arty equipment which will wear out within the 20 -year plant life will need to be replaced. The MPCA's facility planning guidelines require that an equipment replacement fund be established for this purpose. Table 3 identifies is a list of equipment which is expected to require replacement during the 20 -year plant life. The replacement cost is convened into a present worth cost and subsequently to an annual replacement cost which is utilized In calculating the equivalent annual oasts for the facility. RCM Pago vi City of Monticello Table 3 Equipment Replacement Cost Monticello Wastewater Treatment Facility Opetntion and Malntenon" A significant portion of the total annual cost of wastewater treatment is the day-to-day operation and maintenance expense. These costs are presented on the following page. In accordance with MPCA cost-effectiveness analysis guidelines, these costs represent an nvernae cost over the 20 -year design period not considering the effects of inflation. Inflation may cause the operation and maintenance costs to be greater than those used in the cost-effective analysis. However, it is assumed that the results of the cost analysis will not be affected by changes in the general level of prices because all prices will tend to change by approximately the same percentage. The following categories of costs have been considered In estimating the total operation and maintenance costs: tabor, power, other utilities, chemicals, materials and supplies, laboratory testing services, professional development/training, insurance, support services, and equipment replacement costs, RCM Page vii City of Monticello Present Equipment Item Lih ftlacement Cost Annual Replacement (Years) (Dollars)• (Dollars) 1. Grit System 20 — 2. Preliminary Screening 0 — 3. Raw Wastewater Pumps 15 50,000 5,500 4. Rotors 20 — 5. Blowers 20 — — 6. RAS/WAS Pumps 15 75,000 8,200 7. Final Clarifier 20 8. Chemical Feed 10 50,000 7,000 9. Digester 20 11. Sludge Thickener 20 — Opetntion and Malntenon" A significant portion of the total annual cost of wastewater treatment is the day-to-day operation and maintenance expense. These costs are presented on the following page. In accordance with MPCA cost-effectiveness analysis guidelines, these costs represent an nvernae cost over the 20 -year design period not considering the effects of inflation. Inflation may cause the operation and maintenance costs to be greater than those used in the cost-effective analysis. However, it is assumed that the results of the cost analysis will not be affected by changes in the general level of prices because all prices will tend to change by approximately the same percentage. The following categories of costs have been considered In estimating the total operation and maintenance costs: tabor, power, other utilities, chemicals, materials and supplies, laboratory testing services, professional development/training, insurance, support services, and equipment replacement costs, RCM Page vii City of Monticello The costs were established by starting with existing operation and maintenance costs and expanding them for the oxidation ditch altemative as follows: J Labor - The same labor cost is anticipated for the oxidation ditch alternative as the other alternatives. O&M Cost - At normal operating conditions, the aeration rotors will draw 188 horsepower. Assuming 85% efficiency, the electrical consumption could be 165 kWb/hr or 1.45 million kWh/yr. At 4.6a/kWh, the aeration cost is S66,000/yr. To this the digestion and remaining electrical usage of about $38,000 per year must be added Chemical Cost - For the volume of lime used, lime may be purchased in bulk Current hulk prices are appmximately 601b hydrated lime. At 375 tons time utili2ed per year, the annual chemical cost associated with time treatment is about 545,000. Sludge Hauling Cost - Since 505ro more solids will require disposal with a time stabilized sludge than current sludge, the sludge disposal costs are expected to be greater. The actual increased cost of sludge disposal is difficult to quantify. x Table 4 identifies the anticipated annual operation and maintenance costs of an oxidation ditch plant with aerobic sludge digestion and lime stab&ation. Table 4 Estimated Operation and Maintenance Costs Monticello Wastewater Treatment Facility 1. Labor andiicnefits...................................................... S280,000 2. Electricity............................................................... 104.000 3. Other Utilities............................................................ 11.000 4. Chemicals ........... ..................................................... 79,000 5. Materials and Supplies ,.................................................... 68,000 6. Testing.................................................................. 11,000 7. Professional Development/Training .............................. . ... ......... 4,000 8. Insurance ..................................... . .......................... 12.000 9. Support Services ...... . ........ ,........................................... 1S.9B41 TOTAL .................................... $584,000 RCM Page viii City of Monticello 1 Life Cvcle Cosy Analysis Life cycle cost analyses are undertaken in order to determine the life cycle of the project when all economic factors are considered. To do this, capital costs, salvage values, and operation, maintenance, and replacement costs are all taken into consideration. Table 5 presents the total equivalent annual costs for the oxidation ditch treatment alternative. Table 5 Total Equivalent Annual Cost Oxidation Ditch Alternative Monticello Wastewater Treatment Facility 1. Totalestiutatcd project capital cost ...................................... $10,620,000 2. Estimated present worth salvage value ........................................ 582,000 3. Estimated equivalent annual construction cost (S/yrr ) ......................... 1,002,000 4. Estimated equivalent annual salvage (S/yr' ).................................. (55,000) 5. Estimated annual O&M cost ............................................... 584.000 6. Estimated annual replacement cost ........................................... 19,000 7. Estimated total equivalent annual cost ..................................... S1,550,000 rAmortUM 20 years at 7% (crf o .09439) The construction cost for an oxidation ditch at the existing site Is estimated to be about 11 percent lower than the trickling filter/activated sludge alternative. The operation and maintenance cost may be up to 1517o greater than the trickling filter/activated sludge alternative — depending upon how the City handles the sludge. By combining the capital cost, operation and maintenance cost, replacement cost, and salvage value, the total annual life cycle cost of an oxidation ditch at the existing plant site is slightly higher than the recommended trickling filter/activated sludge alternative. RCM recommends further investigation of implementing an oxidation ditch alternative along with revised solids handling facilities. There are several noneconomic advantages of a new oxidation ditch facility at the existing site including simpler operation, greater ease of future (beyond 2020) expansion, and less potential for odors. These advantages would be discussed in greater depth in the facility plan "tune-up". RCM Page ix City of Monticello MEMORANDUM i TO: Jon Peterson, OSM FROM: Larry Anderson, RCM RE: Pzeliminary Cost Estimate Treatment Alternatives Monticello Wastewater Treatment Facility RCM Project No. 12211.01 DATE September 9, 1994 This memo contains a preliminary cost estimate for the four treatment alternative investigated to treat the Monticello wastewater. All of the alternatives would be located at the existing plant and would be deigned to trot the wastewater flow and load that would be Se ntrated over the mn 20 years. The flows and loads were previously established in Technical Memorandum No. l which was negotiated with the City. The design parameters for the treatment fatty would be as follows Design Year - 2020 Population - 12,841 Flow - Average dry weather (ADW) - 1.82 mgd Average wet weather (AVAV) - 1.98 mgd Maximum Wet Weather (MWW) - 2.27 mgd Peak homty wet weather (PHWW) - 4.82 mgd Peak instantaneous wet weather (PIW W) - 5.19 m8d BOD - Average - 5,200Ibs/day Maximum month - 7,400lbslday Maximum Week - 8,1001b3lday Maximum day - 9,000Ibs/day Total suspended solids (ISS) Averap - 4, 100Ibslday Maximum month - 6.1001bsldq Maximum week - 6,700 ibs/day Maximum day Uautd Simm Proem - 9,7001ba/day The following treatment units and processes Were hawed on the preliminary screening which was predously performed and submitted to the City in a meQaadxtm loud June 27, 1994. lbew alternatives are defined as: 1) Upgrading of the existing fa&ty: 2) '!*P -stage sickling ifiter, 3) Activated sludge; and 4) Oxidation ditch 1 Memorandum September 12, 1994 Page 2 Uoatade Fadstine Facility The design parameters and sizing parameters to upgrade the existing facility are listed in Appendix A. This facility would consist of the following items. Preliminary Treatment This alternative assumes that preliminary treatment would continue to be provided in the existing preliminary treatment room. Preliminary treatment would consist of a manually cleaned bar screen and a vortex-type grit removal system. Both of these units would be installed in the existing preliminary treatment room. The preliminary treatment room currently contains a commmuter and a grit removal system. The existing equipment would need to be removed and disposed oL The channels which carry the wastewater are not of the required size or configuration which would accommodate the new bar screens or removal facilities; therefore, it is assumed that the slab in this area would need to be demolished and reconstructed. A significant part of the dissatisfaction with the existing preliminary treatment facilities are that the operators are required to manually carry the screenings and grit to the surface for removal and disposal. This alternative assumes that the screenings and grit would be mechanically conveyed to the ground floor where they would be deposited into a du mpster. A new overhead door would be installed in the 'back' wall of the control building so the screenings and grit could be loaded directly into a waste hauling truck. The screening and grit room would occupy the space currently used by a lavatory and the odor control room. these facilities would need to be relocated to another location. jtaw Wastewater Pumnins The raw wastewater pumping faelitiea would consist of removing the eudsting four raw wastewater pumps and replacing them with three new raw wastewater pumps. The existing dry pit area would be renovated with a circular stair, new piping for the new pumps and a beam and trolley installed above the pumps for pump removal. The three new raw wastewater pumps would not have sufficient capacity to pump all of the raw wastewater during periods of high flow. Two (2) new raw wastewater pumps would be installed in the reconstructed preliminary treatment Croom. These pumps would either be shaft-driven wet pit-type pumps with the motor mounted above the wet well, or submersible pumps. The piping from the two wet weather pumps would be extended through the wall Into the existing pump room area and would be constructed along side the existing raw wastewater line. Memorandum September 12, 1994 Page 3 Primary (3arifier The existing primary clarifier is inadequately sized for the design conditions. The ousting primary clarifier would be demolished and replaced with two new circular primary clarifiers_ The new primary clarifiers would be built such that the wastewater flows which exceed peak hourly flows would overflow a third gate structure to the equalization basin. Sludge piping from the new primary clarifier would be connected to the existing sludge lines. Sludge would be handled by the existing ODS sludge pumps in the basement of the pitting control building. Effluent from the primary clarifier would Dow by gravity to new and reconstructed trickling filters. Tricklin¢ Filters The wastewater would flow to a splitter st rumnue which would split the wastewater two ways. The existing trickling filters would be reconstructed by. a) increasing the depth to 10 feet; b) removing the existing superstructure and constructing a new superstructure; e) replacing the rock media with a new synthetic media; d) installing a new distributor-, and e) placing a new cover over the tickling filtem 'The new trickling filter would be eDestruacd similar to the refurbished trickling filters. They would have a media depth of 10 feet and a 40•foot diameter, simx7ar to the existing trickling filter. lataMediate ClarTaramaRjU The effluent from the trickling filters would flow by gravity to the exiting intermediate clarifier for solids removal and subsequent wastewater to the activated sludge unit. The existing sludge pumps would continue to be utilized for handling of the wastewater sludge. The intermediate clarifier would be significantly overloaded; however. it is intended to construct a new clarifier. The wilds which would overdoes the weir of the clarifier would be handled In the subsequent activated sludge treatment unit. Activated Sludge The activated sludge system would consist of utilizing the existing too activated sludge basins and constructing two new aimflar aired aetivated sludge half- The existing jet aeration system would be replaced with a Dae bubble diffuser system. 71te csds n blowers would be inspected and, if necessary, placed with new blowers. Return sludge pumping and waste sludge pumping taciQties would be split. 71e Memorandum September 12, 1994 Page 4 existing pumps would continued to be used as they are. New sludge pumps would be associated with the am activated sludge tanks and would be installed in a new returm1waste sludge pumping building. Final Clarifier The existing two final clarifiers would continue to be used. Two new 46 -foot diameter final clarifiers would be cons muted to be operated in conjunction with the new activated sludge tanks. Disinfection From the final clarifier, the wastewater would flow to ultraviolet disinfection facilities constructed in the existing final clarifier tankage. Sludge Handling OSM Odor Control Odor control facilities will be installed at all buildings and structures handling wastewater and sludge. The system would be designed such that makeup fresh air will be drawn into occupied rooms being occupied such as offices, lavatories, control rooms, etc. The exhaust air would be transferred into the rooms which have open wastewater or sludge. Additional air makeup would also be provided to these rooms, in the event that greater volumes are required than could be supplied from the occupied rooms. The exhaust air from the various structures and rooms would be ducted to either an activated carbon or a wet chemical scrubber system. Mte snubber system would be Installed in a new building located in the general vicinity of the sludge haadiittg Wilities. The existing City the effluent standards require secondary treatment It is possible that the Minnesota Pollution Control Agency will impose stricter standards at some future date. For that reason, it is necessary that the facilities be designed to provide additional treatment as follows: a) iaaeased treatment to produce an effluent BOD of 10 milligrams per liter, b) phosphorus removal; and c) n1t illation. Each of the facilities would be designed so they may be readily expanded to provide the additional treatment. For example, the second stage activated sludge would be zlz for nitrification of the wastewater. Chemicals such as alum could be added to rho sewer between the activated sludge and the final clarifiers for phospbow removal F Memorandum September 12,1994 Page S The second alternative investigated is the feasibility of eliminating the activated sludge pordm of the wastewater treatment ptam and to construct a two-stage trickling filter. 11te required treau2nat units would be as follows: PrOmnaty Treatment The preliminary treatment would be the tame as would be required to upgrade the aostlog facility. Raw Wastewater Pumeln2 The raw wastewater pumping would be the same as required to upgrade the existing treatment faa]ity. Mmary Clarifier The primary darifier would be the same as required for upgrading the facilities. A twoatage trickling filter system would be required. Waatewter from the primary dari.fiers would How into a wastewater pumping station and then be pumped to the first two trickling filters. Fluent from the trickling filters would flow by gravity to the cA ting intermediate clarifier. The wastewater would tbm be pumped by the intermediate pumps to the second stage triching filter. The sludge from the intermediate darifier would be handled in the acme manner the the sludge from the previous altemative would be handled The second nage trickling filter would mocM the pumped wastewater from the intermediate du fier. A recirculation wet well would be coastructed at the tsietling filter site and recirculation pumps would recirculate flow to both the primary and the secondary trickling filters. 7Tse nut of the pr(m u7 effluent pump station and the mcirattadon pump nations are b duded in the trieskllng fitter cost estimate Mie efiluesn from the wound amp trick tug filter would floc to a splitter structure whicb would split the flow to afoot diameter Hnd darMers. From the final dariifiers. wastewater would flow to eMuent disinfection. A sludge pumping building ` would be constructed for the sludge pumps which handle the sludge from the final clarifiers. Memorandum September 12, 1994 Page 6 Disinfection As was discussed in the previous alternative, an ultraviolet disinfection facility would be used to disinfect the wastewater prior to discharge into the Mississippi River. Activated Sludge This alternative investigates the cost of eliminatingthe tridding filters and comtructingonlyactivated sludge facilities. In this alternative, it is assumed that no modifications to the preliminary treatment facilities would be done. The existing facilities would be allowed to receive the raw wastewater as now occurs. Wastewater would then be pumped to a primary screening facility. taw wastewater PumvinS The same raw wastewater pumping modifications discussed in the previous two alternatives would be constructed in this alternative. Primary Screening Under this alternative a combined fine screen and grit removal facility would be constructed in the vicinity of the existing Dow diverter structure. Wastewater would be pumped to a Dow splitter structure which would split the Dow to four 6 -foot long static screens. The solids and coarse grit would be removed on the careens and would collect in a screw conveyer located in the facility. The conveyor would dewater the solids as it conveys them into a dumpster. The underfloor from the static screens would collect in a vortex grit removal facility such as the Teacup® as is manufactured by Eutel4 Inc Activated Sludge Effluent from the primary screened facility would flow by gravity to the eidsting activated sludge tanks. Here the wamwater would receive the first stage of treatment. The wastewater would flow from the existing tanks into a sceond set of activated sludge basins which would be approximately twice the size of the existing basin. Here the wastewater would receive additional oxygenation. Fine bubble diff4sers would be constructed in both the existing basics and in the new activated sludge basins. The existing blowers would be inspected and, if necessary, replaced. New blowers would be constructed to handle the additional aeration capacity. Final Clarifiers Effluent from the activated sludge basin would flow by gravity to two 60•foot diameter final clarifiers. Sludge from the final clarifiers would be removed with waste activated and return activated sludge pumps and would be pumped to the activated sludge tanks. The waste activated and return activated sludge pumps would be located in a pumping station which would also house additional blowers. From Memorandum September 12, 1994 Page 7 the final darifien, the wastewater will flow to disinfection facilities which would be similar to that discussed in the previous two alternatives. The fourth alternative which was investigated btoreplace: the ezdstingbiological treatment units with as oxidation ditch process. An oxidation ditch is an activated sludge process which operates in the extended aeration mode and which provides oxygen to the wastewater through brush rotors Components of this alternative would be as follows. Preliminary Treatmxest Me preliminary treatment facility would be aimila to what was discussed in the activated sludge, i.e., no changes to the existing facilities. Raw Wastewater Pumping The raw wastewater pumping facilities would be similar to what was discus d in ell three previous alternatives. primau Saeenina 'Ilse primary saeeningfaelity for this alternative vmuld be the name as was discasscd for the activated sludge. Mdation Ditch Oxidation ditches would be utilized in this alternative. The reason fair (4) oxidation ditches would be inwalled is so that the arrest wastewater now and load ate significantly less than what ultimately would be ccwu=eted. Far that ressm the City may wish to comstract only two ditchm at this time and as the wastewater flows increase additional ditches could be added at a later date. 'Ibis alternative includes foto 46 -foot diameter Seal dari(aL As was the case with the oxidation ditches the firm clarifier would be alml6cmat underloaded Wtially, so by constructing --TI diameter duffien at the time, the plant could operate more within its design capacity and sddidoml anal datf9en would be added at a hues date. if the City should choosethe two 46 -foot diameter anal dariaen may be replaced vith Wow diameter clarifiers simfla to what was disarased in the previous alternative. Memorandum September uM4 Page 8 Also included within the costa M the Seal dadlers b an estimate of the cost to construct a ret®/wasN activated d udgo pumping badlity. Tib return activated and waste activated sludg+ pumping f coq would be constsucted in an area between the ozsdation ditdics and the final clarifier. The effluent from the final clarifiers could be conveyed to an ultraviolet disinfection faality as is diseased in the alternatives listed above. I 1. 2 3. 4. S. 6. 7. 8. 9. 10. 11. 12 13. 14. 15. fL+ TABIS 1 MOM710ELF WASn WATER IM AIMENT FAcnm Upgrade F-Isft Facing Preliminary Treatment S 350.000 Raw wastewater Pumping 150,000 Primary Clarifier 700,000 Yard Piping (wastewater) 190,000 'haling Filter 840,000 Intermediate C7ui8er/Pnmping 60,000 Activated Sludge 480,000 Final Clarifier 11000,000 Dialnfecdon 450,000 Odor Control 1,400,000 Demolition 30.000 Mectrlcal (0 10%) 300.000 Mechanical (- 7%) 300,000 Replace Existing Sludge, Pumps and Blowers 90,000 Sludge 300.000 Subtotsb 110,140.000 CantinscMics 1.000,000 Total BdloutUd Cost 111.140.000 Round off to: 111,000.000 Pccpu cd September 9, IM 1. 2. 3. 4. S. 6. 7. a 9. 10. 11. 12. 13. 14. TABU 2 MON nC6I1A WASTEWATER TRFAThUNT FAC0l11Y Preliminary Treatment Raw Wastewater Pumping Primary Clarifier Yard Piping Wastewater Triciding Filter Final Clarifier Demolition Odor Control Hectirsl Mechanical Replace Frdsting Pumps. etc Sludge 1wo,stage T.F. subt" Total CondrocOw Round off tat S 350,000 150,000 700,000 210,000 2,400.000 1,000,000 450,000 50,000 1,400,000 500,000 300,000 50,000 3,600,000 $11,160,000 1,100.000 $12,2601000 512.000.000 v } Prepared September 8. 1994 I 1. z 3. 4. S. 6. 7. f3. 9. 10. 11. 12. 13. 14. TABLE 1 MOPfli(3I" WASIEWATEMTRFATM3W FACEUTY Adhated Sludge Preliminmm Raw Pumping Yard Pon Omstewater) AaMted Stodge Final Clarifier Disinf cm Odor Control Demolidon Electrical Sludge Reo— PumpVBW-n Contingencies Subtotal Total Sdtmated Cast Bound Off cm S - 13%000 (13%000 210,000 T10,000 1,700,000 43%000 1,40%000 30,000 30%000 300.000 3,20%000 3%000 $ 9,61%000 %%000 $10.51%000 $10,500000 Prepared September S. 1996 1. 2. 3. 4. S. 6. 7. 8. 9. 10. 11. iz 13. 14. TABLE 4 MONTICELLO WASTEWATER 7RFi►17r M MalairY Preliminary Treatmew Raw Pumping Primary Screening Yard Piping aaddation Ditch Fnral Clarifier Demolition Odor Control Eeetrieal Mechanical Replace Existing Bluipment Sludge Contingencies Oxidation Ditch Subtotal Tota! Ediumb Cast Round off in S - 150,000 850,000 210,000 2,670.000 2.400.000 430.000 30.000 1,400,000 700.000 300.000 so aoo 3,600,000 $13,810,000 1,200.000 $14,010.000 $14,000,000 Prepared September S. 19% APPENDEE A MONTICELLO WASTEWATER TREATMENT FAC3LW Desim PNtameters Em ADW = L82 mgd AW W = 198 mgd PHWW = 4.82 mgd PIWW = 5.20 mgd Led - BOD Avg Mo. = 3,200 be/day Max Mo. = 7.400 VWday Max Wk = 8.100 lWday Max Day = 9.000 UWday -7w Avg Mo. = 4,100 UWday Max Mo. m 6.100 VWday Max Wk = 6,700 lWday Max Day = Preliminan Tleatmmt screenBU 9.700 nWday E No. of units 1 Width 30 -inch Bar spacing Mesimum capacity 4.8 mo Velocity at average flow No. of units 1 Diameter 8 a Depth 73 f! Capacity 4.8 mgd Cydow 64=6 Screw dassiGer 8nch diameter 1 APPENDIX A 2 (oontimed) 10 R Raw wastewater Pumoine 10 ft wet wen 20 8 x 7s i3 x 7 It At PHWW 8,000 pnoas D.T. ADW 63 minutes MWS 5.8 minutes PHWW o 2.4 minutes PIWW 2.2 minutes wastewater P®ne Number of pumps S Capacity 3 @ 600 pm 2 @ Prhmary Screenina/Ont Removal 2,000 Spm Screen type Static screen Number 4 Opening size 0.0604nch Length 6 R Capadty (each) 13 mgd Grit Removal Type Vortex Number 4 Diameter 60-inch Capadty (each) Primary Ctadfien 13 mad 0: Number 2 Diameter 10 R Depth 10 ft 1BlOU At AWw 600 Spalls At PHWW 1,460 gM Rcmonl BOD 25% S.S. 70% 2 APPENDI% A ( Trickling Filters (for two-stage TFIA-S) Number 4 Diameter 40 ft Depth 10 R Volume 50,000 d Loading 110 lbs BOD/1.000 d/day BOD removal 8096 BOD remaining 1,100 lbs ROD/day Intermediate t7arwer (existing) Number 2 Length 36 ft Width 10 8 Side water depth 10 It S.S.R at AWW 2,750 gpsfd at PHW W 6,700 gysid THOU Fat- (far twoetap M Number 4 (two primary, two secondary) Diameter 50 ft Depth 24 It Volume 94,000 d Loading Primary 60 lbs DOM,= dlday Removal primary 83% Secondary 10 lbs DOW.= d (for twostago TWAS) Number basins 4 (two cW= two naw) Sine (esdt) 40 R x 40 R ar 14 A Volunse (each) 22.400 d Total 89,600 d Loading 12.4 lbs BODA.000 d 0 APPSNDIZ A ( AetivoLted Sludge (AS. alone) Number basins 4 (two a bft two new) Size: Fidstmg 40 ft x 40 ft x 14 ft New 100ftx40ftxl4ft EgLitiSg Volume 44,800 d Loading 140 Ors BOD/1,000 d BOD removal Secondary 70% Volume 126,000 d Loading 1.7 lbs BOD/1,WD d BOD removal Clarifier 90% Foal Number units 2 Diameter 60 ft Depth 14 ft Hydraulic loading AW W o 350 gpsfd PHWW M Oddation Ditch 850gpdfd Number units 4 BOD loading 15 lbs SOD/1,000 d Volume (total) 420,000 d 3.14 mg end 785,000 plions Dimensions cub Channel MM 23 ft overall knob 1841t Rotor requiremeab Mixing 20.000 gal/ft blade Mia rover length 40 MuLdn With nae out of aervloe 60 ftlbarm Organic load SOD 9,700 Ota Nitrogen 730 Ms OY required SOD • Ll no SOD 10.700 Nitrogen 4 VA 07ft N 3,000 Total 11,700 Ora 4 APPEND18 A per Basin 3.425 p 85.6 lb,day/Rlblade 3.561b Oveoatiou 142 ma Cindbadn 39.88 8/blOc ase tb= 2D -ft rotombasia BI -V 2.6 bp/m R corm i 20 8 - 40 me cad 72m 364mch :4&4nch 125 S U.V.., ;.,i,.,. 50% N.O= lsmpa 532 J APPENDEC A MONIICULO WAS17EWATEBTMTb9VT FAMM ® Parameters Flim ADW = 1.82 mgd AWW = 198 mgd PHWW = 4.82 MO PIWW = 5.0 MO Lad. HOD Avg. Mm = 5= DWday bim Mm = 7.40D lWday Mas Wk. = 8.1W TWday Mas Day = 9.00D Wdsy Lam. 1M Avg.Mo.- 6.100 RWday Mho. 0 Wdsy Max Wk = 6.740 Wday MaL Day = Bar 9.7W PAIday NO. Of units 1� j/ Width ^ �" Barspacing Maxim= a"city 4.8 mgd Velocity at avata8p Sow Na. of uW a 1 Diameter 8 e 4.8 mgd Mad► Screw dudit .84adt disocta I F APPEPAM A ( Raw wastewater P=zflw wet Wen 20e:7sa:7a 8.000 saucas D.T. ADW o 63 mbmm� Mws 5.8 minutes PHWW 2.4 mimrtp PSM ww� 2.2 minutes Eno Number of pmnps 3 capadt9 3 ® 600 gpm 2 ® 2.000 gpm Screen type Static scxa Number 4 OpMdq size 0.0604nch Leegtb 6 R capadty (cub) 1.5 mSd Grit BszmW Type Vortex Number 4 Diameter capacity (each) 604 13 qO - -• 'type Malar Number 2 Diameter 10 Q Depth 10 d At AVM 600 gpdd At PHWW Me we Hemay1 BOD 25% S.S. 70% 2 J 1J L APPBNDIZ A `) ( TIIckliBSFiltffi (for two-stage TF/A.S) Number 4 Diameter 40 !t Depth 10 R Volume 30,000 d Loading 110 lbs 130D/1,000 d/day BOD removal 8096 BOD remain" 1,100 Un DOD/day (cestiv Number 2 LAngth 36ft Width 10 8 Side water depth 10 8 S.S.R at AWW 2,750 Wdd at PHWW 6,700 gpatd Tridogg Filter (far two-stage TF) Number primary. two secondary) i Diameter soft S Depth 24 R Volume 94,000 d Loading Primary 60 0!s DOD/1,000 d/day Removal prku" 8996 Secondary 10 Me SODAJW d Awn (mr two-Or TF/AS) Number balm 4 (two cAMM two nerd Size (each) 40 R z 401! s 14.6 . Volume (cub) 2;400 d Total 89,600 d Loading 114 IDs BODV1,000 d 1 3 APPENDIX A, ( (A•8• al=) Number basun Size: Faasting New 18 Volume fandia8 BOD removal SOCCED Volume BOLD removal 4 (two eaistigg two =w) 408:40as14ft' 1001t:40aa148 44,800 d 140 Ilu BOD/1.000 d 70% 000 d (' T Ibs 1300/1.000 e! 90% Final QariHer Number units 2 Diameter 60 a Depth 14 a Hydraulic loading AW W M 350 gpdd PHWW w Ckddation Di M gpsfd Number units 4 BOD loading 15 Iba SODA OW d Volame (total) 420`000 d 9.14 sag Cub 783.000 pUm Dim e> cam Casanel WM 23 a _ Rotor 184 a � f eladn 1 lead 442D.000 0 With one not o1 senIg 60 Qlbasb OwMdclMd BOD 9.700 Brs Mtrogco 750 On 01 required BOD - Ll Be C1120 HOD 10.700 Nitrogen 4 Ops GA N 3.000 Total 1%7001bs 4 r APPEMMA (amahman PCX BUIM itne UY.- ....... Number lamp 5 3AZ 0041digit sain SSAJ nwb'4qib� th osAmwh& IQ M=bsdn 39A ftve " rowm6nin 26 hpAm ft rate: z 20 ft - 40 the cad 364ach x 484rch x 25 ft 50% 532 0 i Twtis +++rte "�M ,?�r^'' � � .....-•-"""....'^ .�"��'' • +,,,.r ear � � .„ ,..... -- .` :.ass / ► + ' �'� � i t'� ;/\i{f��//�1 rf• it � - i . � • .mow. '`