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ITEM 1 WWTF ExpansionVfi"EM 7 0 Y 0 tsTe MIN NESOTA F MEMORANDUM TO: Public Works Subcommittee FROM: Lori Johnson, City Administrator DATE: October 16, 2015 SUBJECT: WWTF Expansion As previously planned, Scott Schaefer of AE2S will be at our meeting to provide an update on the WWTF Expansion project. Below are the main items of discussion at the meeting: • East WWTF Biosolids Processes Capacity Analysis Tech Memo • West WWTF Liquid Train Process Evaluation Tech Memo • West WWTF Digester Alternatives and Recommendation • Odor Control Bid Alternate • Schedule and Next Steps We are on schedule to bid the project early 2016 with substantial completion in fall of 2016. It is important that any specific suggestions, issues, or concerns you have with the proposed design and expansion plans be raised now before final design. Scott will go through design, bid alternate(s), and timeline in as much detail as you want at the meeting to gather your input. Additionally, the original project schedule included a check -in with the City Council before final design; that meeting should occur soon to keep the project on schedule. There is one other wastewater item staff has discussed and wants to inform you of before it goes to City Council. In addition to this current project, the 2016 CIP includes a recommendation to fund a WWTF Master Plan that is essentially a comprehensive engineering study of future wastewater requirements and how to best meet that need from a citywide perspective. It is important to plan now for future wastewater demands to secure additional property if needed to accommodate plant expansion, to change the east/west flow before development occurs in areas subject to change, and to begin financial planning to ensure funds are available as future phases of expansion are built. Table g e QoWon of Probable ConstrucUnn Costs e Jest IbAJUJI TF Digester Impr®vernents b.Orpro'hable'-t6ristruction Costs .. Pipe Diffusers Jet Aeration e- DescTiption Cosa Mobilization, Bonds, Insurance $100,000 $110,000 Site Work $108,000 $113,000 Process Equipment and Piping (Includes Site Work Piping) $693,000 $656,000 Structural $263,000 $415,000 Architectural $0 $0 Mechanical $0 $0 Electrical/Controls $183,000 $198,000 Subtotal $1,347,000 $1,492,000 Construction Contingencies (15%) Opinion of Probable + on_CQsts Design Fee $199,000 $1,546,000 $126,900 $221,000 $1,713,000 $126,900 Other Engineering, Legal, Admin (10%) Opinion of Probables + $154,600 11 $171,300 1 1# HCLJ KecOmme"Ud 1Q" Potential Bid Alternate Items 1) Additional Site Paving 2) Odor Control System Table 2 — Net Present Worth and GIpinion of Probable MV1 Costs �Designn Flow Easis� Net Present Worth . O&M Costs OtsegoDrop Pipe Diffusers Description with Shear .- Cost Labor $16,000 $21,000 Power $51,000 $78,000 Equipment Maintenance $5,000 $5,000 Miscellaneous $500 $1,300 Opinion of Probable Annual O&M Costs $72,500 $105,300 ®&M Net Present Wonth2 $993,000 $1,441,000 Total+ 111 li/ HE2S Recommendation 2An interest rate of 4.0% and 20 year period was used in the present worth calculations. Note: Costs do not include potential Alternates or equipment replacement costs. Otsego Vilest WWTF Digester Improvements Project Update: October 20, 2015 Table 3 o AltemaUves ���9va�tages�©isa�le�an a�oe� Drop pipe d Proven technology and experienced o Additional costs Uf users manufacturer in aerobic digestion o New blowers �� A,%h shear applications o New air piping u gybes o Cost-effective ective alternative a Less control due to mixing and air o New blowers in existing dosing controlled by single piece of structure equipment o No new pumps 0 Proprietary o Low footprint due to deeper aerobic digestion tanks o Lowest O&M o Competitive net present worth o Effective stabilization 0 Simple operation due to use of only blowers ® New equipment (blowers) in single location Set AerratiorF o Proven technology in aerobic ® Most expensive alternative digestion applications. Experienced o New blowers manufacturers. o New air piping o Effective stabilization o New puinps o Higher control due to mixing and air o Expanded footprint for pumps dosing controlled by independent and flushing valve dry pit equipment o Highest O&M and NPW ® Multiple manufacturers o More complex operation due to header flushing o New equipment (blowers and pumps) in multiple locations Table 4 — Future Capital Costs prior to Design Flow • Potential Capital Costs Prior to Design Flow Item Projected .Comments One million gallons (MG) of storage is currently available. To achieve 365 days of storage (no Spring hauling) at design flow/load capacity, additional biosolids storage will be required ranging from 0.30 MG to 0.60 MG based Biosolids $1.31MM - $2.2MM on the performance of the new upstream aerobic digesters. Alternative Storage for sludge storage biosolids disposal methods may also be considered in lieu (or in addition to) biosolids storage expansion and require an in-depth analysis. Additional storage volume can be deferred by hauling to other WWTFs during years with a wet or cold Spring Oxidation Additional off the shelf aerator as facility reaches 0.30 MGD (currently Ditch $115,000 -0.25 MGD) would be required to meet current MPCA requirements for Aerator redundancy. An entire new tank is not required to meet redundancy requirements. Note: Table does not identify cost of replacing existing equipment, which is a typical cost of operating a wastewater treatment facility. Equipment is typically replaced on a 15-25 year timeline at such facilities depending on the equipment, environment, operation, and maintenance. Otsego West WW II F Digester Improvements Project Update: October 20, 2015 Potential Schedule for: "'"JWTF Digester Project Starts Show Weekends Plan Duration by Select Your View Ib /�pN �p�p Task .. Title/Description 0.0 Project Preparation AE2S 6-May-15 20 1-Jun-15 �( 0.1 0.2 0.3 0.4 0.5 Prepare draft digester improvements scope Scoping meeting Revise scope/fee; additional meetings as required Submit scope/fee for City Council Agenda Packet City CounciMeefing AE2S City/AE2S AE2S AE2S/City City 6-May-15 13-May-15 13-May-15 21IMay-15 26-Ma -15 6 1 7 4 1 13-May-15 13-May-15 21-May-15 26-May-15 26-Ma -15 0.6 Assumed Notice to Proceed City 27-May-1 4 1-Jun-15 1,p Preliminary Design AE25 with City 1-Jun-15 61 26-Aug-15 1.1 Preliminary Design activities AE2S with City 1-Jun-15 30 10-Jul-15 1.2 1.3 Equipment pre -selection or pre -procurement Review meetings, revise, confirm with Council AE2S AE2S with City 10-Jul-15 6-Aug-15 20 15 6 Aug-15 26-Aug-15 f 2,p Final Design City with AE2S 26-Aug-I5 65 25-Nov-15 2.1 2.2 Incorporate preliiminary design comments, detailed design 75% submittal, review, and review meeting AE2S City with AE25 26-Aug-15 29-Sep-15 25 10 29-Sep-I5 12-Oct-15 2.3 Bid document preparation AE2S 12-Oct-I5 20 6-Nov-15 2.4 Final review, QA/QC City with AE2S 6-Nov-15 10 19-Nov-15 2.5 2.6 2.7 V) incorporate final revisions Final City Council approval Submit package to MPCA Regulatory Review AE2S City AE25/Ci MPCA 19-Nov-15 25-Nov-15 25 Nov-15 25-Nov-15 5 1 1 40 25-Nov-15 25-Nov-15 25-Nov-15 19-Jan-16 To Bidding/Award AE2S/City 19-Jan-16 40 14-Mar-16 5.0 Construction and Start -Up Contractor 14-Mar-16 150 7-Oct-16 Printed/Updated 5/12/2015 AE2S