Agenda Item Wording:
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Biosolids Hauling and Disposal - Approve Contract Change Order No. 1with WTB Inc. in the amount of $105,256.00 and appropriate an additional $225,000.00 to cover the additional costs of hauling and disposing of the 2023 biosolids stockpile at the Visalia Water Reclamation Facility (WRF).
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Deadline for Action: 9/16/2024
Submitting Department: Public Works
Contact Name and Phone Number: Ben Litwack, (559)713-4671, ben.litwack@visalia.city
Department Recommendation: Staff recommends that Council approve Change Order No. 1 with WTB Inc. under Purchase Order #3568 in the amount of $105,256.00, and also approve the additional appropriation of $225,000.000 from the Waste Water Operations Enterprise Fund (431 Fund) to cover the additional costs of hauling and disposing of the 2023 biosolids stockpile at the Visalia WRF.
Background Discussion:
The Visalia Water Reclamation Facility (WRF) has generated the largest biosolids stockpile in the history of the plant during the 2023 operational year. The total stockpile for 2023 has reached unprecedented levels, with an estimated 9,400 tons of biosolids requiring transportation and disposal. The City’s current Waste Discharge Permit mandates the removal and disposal of the entire 2023 biosolids stockpile by the end of this calendar year. After an analysis of historical data, staff has determined the following factors, which have all contributed to the increase in the amount of biosolids.
1. Increased Industrial Loadings: Our largest industrial users have increased their flows and loadings over the past few years. When combined, these users contribute 25% of the total flow entering the WRF. The average solids concentration of this flow is anywhere from 50%-150% higher than a typical residential flow and the peaking factors on some days can exceed 800%-900%. Staff has had difficulty in quantifying the exact contribution since our monitoring programs are set up to calculate billing and confirm compliance with discharge permits based on averages of 24-hour composite samples as is best practice, not to calculate the exact amount of solids being discharged on a daily basis. At least one of these industries is in the process of installing a treatment system and another is in the process of determining the feasibility of a similar measure. Staff believes that these measures have the potential to significantly mitigate the amount of solids entering the WRF in the future.
2. Repairs on Digester 4: In mid-2022, the WRF had to temporarily decommission Digester 4 to allow for repairs and rehabilitation. The loss of this digester at the same time that solids loadings were increasing, leveed an increased level of strain on the remaining digesters. Higher biosolids flows being distributed amongst fewer digesters led to the inefficient processing of solids, which would have had an impact on the amount of biosolids ultimately being dewatered and stockpiled. Digester 4 has since been repaired and recommissioned and solids processing levels and process efficiency are back to normal levels.
3. Overall Operational Inefficiency: The increase in volume and change in constituent quality of the incoming flow to the WRF since the last plant upgrade in 2018 have added strain on all downstream processes. This additional strain could potentially be reducing the amount of solids destruction that would otherwise happen when the facilities operate under optimal conditions. This issue is being addressed in our Near-Term Solids Handling Improvement projects, which are currently under design and scheduled to be completely implemented by 2028.
The City currently has a purchase order with WTB Inc. for the transport of biosolids to the Tulare County Landfill. The estimated balance remaining under that purchase order is $1,744.00. WTB bills the City at a rate of $160/hr for the transportation of the biosolids. Staff estimates that an additional $107,000.00 will be an adequate amount to transport the remaining 2023 biosolids pile, so the Purchase Order # 3568 will need to be increased by an additional $105,256.00. This request was reviewed by the City’s Change Order Committee on August 28, 2024, and is recommended for approval.
Additionally, disposal efforts are constrained by the limitations imposed by the Tulare County Landfill, which permits a maximum of 300 tons of biosolids to be disposed of per day, also limited to three days per week. Despite ongoing efforts to maximize disposal operations, only 3,133 tons of biosolids have been removed to date, leaving an estimated 6,300 tons still requiring transportation and disposal. Staff is confident that with this change order approval, the disposal can be completed within the required time period.
The Tulare County Landfill has also recently imposed an additional $10.00 per ton “special handling fee” for the processing of biosolids, increasing overall per ton disposal fee by 83% over last year’s rate. Our increased biosolids production and this increased per-ton fee have led to a dramatic increase in the cost of disposal. Due to the rapidly changing regulatory environment, the Tulare County Landfill has refused to formalize a contractual agreement with the City. As a result, the City has been paying for biosolids disposal on a ticket-by-ticket basis at a rate of $22.00 per ton. Staff estimates that an additional $150,000.00 will be adequate to dispose of the remaining 2023 biosolids pile.
The budget for hauling and disposal of biosolids for Fiscal Year 2024 is $150,000, of which an estimated $66,973.96 has been spent at the Landfill and $48,592.00 has been spent on hauling, leaving $34,434.04 remaining. An additional appropriation of $225,000.00 would be adequate to remove and dispose of the remaining 2023 biosolids stockpile and potentially cover any minor contingencies that may arise. It is important to note that the industrial users who have been contributing a significant portion of the solids loadings responsible for the current situation, have been paying for these increased quantities as well as penalties on a monthly basis for their permit exceedances. Therefore, the City has generated additional revenue to account for this increase in operation expenditures.
Fiscal Impact:
1. An additional $225,000.00 will need to be appropriated from the 431 Fund and transferred to 4336-55700.
2. $105,256.00 will need to be added to P0 #3568 with WTB Inc.
Prior Council Action: N/A
Other: N/A
Alternatives: N/A
Recommended Motion (and Alternative Motions if expected):
recommendation
Approve Change Order No. 1 with WTB Inc. under Purchase Order #3568 in the amount of $105,256.00 and appropriate an additional $225,000.00 from the 431 Fund to 4336-55700.
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Environmental Assessment Status: N/A
CEQA Review: N/A
Attachments: CO#1 - P03568.pdf