INTEROFFICE MEMORANDUM

Transcription

1 INTEROFFICE MEMORANDUM Date: Dec 3, 2015 To: Boise Public Works Commission From: Paul Zimmerman, Matt Hightree, and Jim Pardy Subject: Directors Report - Sewer Goal: Develop and implement a long-term wastewater treatment plan that addresses growth, regulatory issues, and reuse taking into consideration environmental, social, and financial impacts. Clean Water Section Status Major Projects: Wastewater Facilities Plan The current Wastewater Facilities Plan 2020 was adopted by City Council in July It identified the need to perform additional evaluations to determine how best to handle future growth and long-term regulatory compliance issues such as temperature and phosphorus. In early 2015, a team led by Brown & Caldwell which included CH2M Hill, J-U-B Engineers, EcoNorthwest, RBCI, and SOVRN was selected to perform these updates. Work phases have been defined, and the first phase began in November, This work is needed to meet the requirements of our existing and future NPDES wastewater permits and to meet the needs of our existing and future customers. Currently $2.25 million remains in the facility planning budget. Related planning work includes: A task order started April 6, 2015, to be complete by December 31, 2015, for $78,837 with HDR to update the facility plan for the Twenty Mile South Bio-solids Application Site (TMSBAS). Updates include expansion of irrigated area, new office space, additional bio-solids storage bunker space and higher nutrient loadings from the new chemically enhanced treatment process at the Lander Street Wastewater Treatment Facility (WWTF). Two task orders with HDR Consultants to to help with our upcoming NPDES permit re-application and to help analyze the new Biotic Ligand Model (BLM). The costs to perform this work are $137,217 for the permit re-application work and $22,983 for the BLM work. BLM is a tool used in aquatic toxicology to examine the 1

2 bioavailability of metals in the aquatic environment and the affinity of these metals to accumulate on gill surfaces of organisms. Temperature Mitigation Studies The Fresh Water Trust (TFT) is continuing to investigate potential temperature offsets that would be created due to river restoration projects. The current task order is for $98,000. There is approximately $78,000 remaining in the budget. West Boise Phosphorus Removal The total estimated capital cost of West Boise phosphorus removal facilities is $33,000,000 (Enhanced Biological Nutrient Removal, or EBNR, and Struvite Production Facility). The EBNR Improvements contractor, RSCI, started work Oct 14, Through Oct 2015 $16,421,623, or 99.0 percent, of the work has been completed. Through Change Order 14, 6.3 percent of the original bid amount had been added to this contract. Process flows were introduced to the new EBNR equipment and systems on May 11, A process upset occurred near the end of September when the contents of one fermenter tank was transferred to the other tank. At the end of October the plant biology appeared to be stabilizing, with effluent total phosphorus (P) averaging 791 µg/l from Oct 20 through Nov 11 (eleven samples), although a rise in these levels between Nov 18 and Nov 22 demonstrated how sensitive the P-removal biology is to many variables at the WWTF. The NPDES limit starting May 1, 2016 is 600 µg/l. Process optimization tests are underway from October through December. A few operational challenges continue to be addressed. The focus of project management has shifted to process testing and optimization and to final modifications of the fermenters. The Struvite Production Facility (SPF) was awarded as a design-build (D/B) project. Since October 2012 City staff has been operating the facility using filtrate from the Belt Filter Presses (BFP), which dewater digested sludge from West Boise and Lander St. WWTFs. In Sept 2015 P-rich filtrate from West Boise's biological process also began to be treated, and struvite production has increased between 3 and 4 times compared to BFP filtrate only. The struvite heat treatment system required to satisfy EPA s 503 regulations for pathogen reduction in biosolids successfully treated multiple batches of struvite during Oct 2015, and City staff began to operate this portion of the SPF in November. However, various problems with the heat treatment system continue to plague the operation, and heat treatment was suspended early in December pending modifications to the heat treatment air system. D/B contract costs for the SPF are $4,709,545 through Change Order 6. Staff anticipates the D/B contract final closeout will be issued by the end of January, West Boise Capacity Improvements: Anaerobic Digestion and Dewatering The project definition changed in January, 2015 to focus on increasing capacity for digestion and dewatering of sludge. A budget of $8.9 million is approved. HDR is the design professional selected from five firms that provided proposals to complete this work. The services agreement with HDR was authorized on August 11, 2015, and the task order for preliminary design was approved on August 21, The predesign report is expected at the end of April

3 Dixie Drain Phosphorus Removal Brown & Caldwell is the project consultant. Work started in 2010 and has overcome challenges with NPDES permitting and protests of both the water right and the Canyon County conditional use permit. Final design was completed in April, The Construction Manager/General Contractor (CM/GC), McAlvain Construction, was actively involved in design review and optimization for construction from October, 2014 when their contract was approved until the end of the design period. Construction work was split into two stages to accelerate efforts. Stage 1 began in April, 2015 on the earthwork mass excavation. Stage 2 was approved by Council on July 28, The Guaranteed Maximum Price (GMP1 plus GMP2) for the project is $15,968,564. At the end of October the budget was 37% spent and the CM/GC continues to make excellent progress. Some of the NPDES permit milestones for completion of design and permitting have been or will be missed due to the delays caused by the permitting processes. Staff is communicating with EPA and DEQ concerning the schedule issues and expects both agencies to approve a compliance schedule modification. Final completion of construction is currently anticipated in mid-2016, a few months after the NPDES compliance date to start operation in May, The current approved CIP budget for the Dixie Drain project is $21,901,499. West Boise Combined Heat and Power (CHP) or Renewable Natural Gas (RNG) and Food Waste Receiving This project anticipates constructing facilities to collect food waste and brown grease to enhance methane production at the West Boise and to reduce waste to the landfill. The methane gas produced will either be used by generators to create electricity or will be sold to Intermountain Gas Company. The CIP budget is expected to be requested for FY17. Design work is planned to be done that year, with construction to be completed in FY2019. Lander Street WWTF Plant-Wide Improvements The City s current NPDES permit for Lander St. requires that if the facility is retained by the City (in lieu of consolidating all treatment at the West Boise WWTF), it must produce effluent with phosphorus of 70 µg/l or less not more than 10 years after the effective date of the current permit, which was September 1, In April, 2015 the PWC approved a staff recommendation to retain Lander St. A CIP budget will be requested beginning in FY17. Project work will include plant-wide upgrades in addition to adding new processes for phosphorus removal. The project is expected to cost $30M to $50M. Design work is planned to start in FY17, and construction must be completed in FY21 to allow a full year of operation before the NPDES compliance date. The project design and construction schedule is expected to be very challenging to meet. Wastewater Treatment Facilities Efficiency Public Works continues to emphasize wastewater facility efficiency and continuous improvement of coordination between engineering, construction, and operations. The Idaho Power Wastewater Energy Efficiency Cohort (WWEEC) program that started in 2014 will wrap up in January, Both WWTFs continue to participate and will qualify for Idaho Power incentive payments. Numerous infrastructure and treatment process changes were made at both facilities in the pursuit of energy conservation. The WWEEC program has raised energy usage awareness throughout the operations and maintenance staff. Public 3

4 Works has seen positive results related to involvement in WWEEC and intends to continue focusing on energy efficiency beyond the end of the program. Issues & Strategies Clean Water: Workload projections are updated annually. The Clean Water Section lost a construction inspector in September, 2014 and added a senior engineer/project manager in November, 2014, resulting in 8 FTE. The workload projection prepared in January, 2015 estimated between 10 and 15 FTEs will be required through 2018 to complete planned projects. The current strategy of hiring consulting services to make up the difference between City staff and required staff will continue. In addition to the projects discussed above, the projections include near-term future projects being driven by NPDES permit requirements. These potentially include filtration at West Boise for additional phosphorus removal and effluent temperature mitigation for both WWTFs. To address the need for the plants to perform very near their theoretical optimums to meet the NPDES permit nutrient limits, two additional positions for a process controls engineer and a process controls programmer were also approved by the City Council in December, The controls engineer recruitment was challenging. The successful candidate started on July 27, He is learning the City systems and is currently updating the control standards, establishing electrical standards, developing electrical distribution models for both WWTFs that are necessary for arc flash analyses, and is managing two electrical CIP projects that were funded in FY16. Discussions of the desired qualifications for the programmer position are ongoing with the Operations Division, and recruitment is expected to begin during the next three months. The intent with the addition of these employees is to maintain and monitor the automated plant controls in a systematic manner that will reduce the incidents of controls failure or of troublesome controls being overridden in favor of manual operation. Sewer Design Section Status New Sewer Line Projects: There are currently no major sewer extension projects (projects greater than $100,000) either under construction or in the design phase at this time. Summary of other projects are as follows: Seven (7) minor City sewer extensions (projects less than $100,000) are either being constructed or in the design phase at this time. Twenty (20) developer projects are either under review or being constructed at this time. Issues & Strategies New Sewer Line Projects: Sufficient budget is available for current and anticipated City sewer projects. 4

5 Status Sewer Rehabilitation Projects: There is one significant sewer rehab project (projects greater than $100,000) in the design phase at this time: Lander Street Trunk Line Replacement: Replacement of approximately 1,500 linear feet of 42 inch sewer trunk line located within the Lander Wastewater Treatment Facility property. Alta Construction was awarded the contract in the amount of $1,027,000. The project is currently being constructed and anticipated to be completed in the spring of There are three (3) small sewer rehab projects either being constructed or in the design phase at this time. Issues & Strategies Sewer Rehabilitation Projects: Engineering is currently redeveloping it procedures and strategies related to the sewer rehabilitation program. The new strategy utilizes a risk base analysis that will more intently look at the consequence of failure along with the likelihood of failure when prioritizing future sewer mainline rehabilitation work. The result of these efforts is intended to provide a more structured program that will provide greater visibility to the critical pipelines throughout the system that if fail could result in significant social, environment and economic impacts. 5