The City invites you to submit a proposal for RWQCF digester cleaning services. The scope of work includes, but is not limited to, the following: The work to be performed by the Contractor under this specification shall consist of removing all sludge, grit and other miscellaneous materials from the digester, screen the material, transfer the screened sludge material to the on-site sludge drying bed up to 1,800 feet from the digesters, inspect the interior of the digester for damage, provide a survey report to the City which adequately describes the condition of the digester and identifies the location and extent of any damage which may cause leakage of digester gas from the digester walls. The Contractor shall furnish all necessary labor, materials, tools, equipment, vehicles, pumps, hoses, electrical cables, fuel and insurance necessary to perform the required services. As part of the City of Turlock Contractor Safety Program, Contractor shall attend an onsite safety training prior to commencement of work. Question Cutoff Date: 4/15/2024
The term of this Agreement shall be three (3) year(s) and will commence on the Effective Date and terminate on the _____ day of ________, 20 (Term) unless the Parties mutually agree in writing to terminate the Agreement earlier or extend the Term pursuant to this Agreement. The City of Turlock (hereinafter referred to as the City) is requesting proposals for qualified firms to provide digester cleaning at the City of Turlock Regional Water Quality Control Facility (RWQCF) located at 901 S. Walnut Rd, Turlock, CA. Digesters are utilized to reduce the volume of organic waste that is removed from wastewater treatment processes. Cleaning of digesters removes solids that will not break down in the digestion process. The anaerobic digester process does not, however, break down inorganic material such as sand and plastic. Regular cleaning of digesters will ensure that proper operating energy efficiency is maintained. Cleaning of anaerobic digesters is standard operating procedures for all wastewater treatment plants. Approval of Contract: 5/14/2024 Services Provided by Contractor: 1. Provide pumps and hoses to pump digested liquids, solids, water used for cleaning, and debris from the anaerobic digester and transfer to the sludge drying beds up to 1,800 feet away and/or tanker trucks. 2. Screen all sludge sent to sludge disposal area. The material shall be screened to 3/16" particle size. 3. Provide trucks to haul grit, rags and other materials that cannot be land applied to State of California licensed landfill site. 4. Provide all miscellaneous tools and equipment including, but not limited to, ladders, ventilation equipment, lights, confined space entry safety equipment, confined space entry attendants, etc. 5. Provide crane or other equipment needed to lift and remove pumps or equipment used to clean digester 6. Thoroughly clean the digester. 7. Remove and replace any access hatches or manways that will be used for digester cleaning and inspection. 8. Provide continuous ventilation and hazardous gas monitoring as required by OSHA. 9. Operate all equipment, and take full responsibility for Contractors employees and any subcontractors in terms of safety and confined space entry. 10. Work area shall be taped off with Contractor being responsible for ensuring a safe working environment within the taped off area. 11. Provide all sampling and analysis required for offsite disposal sites. 12. Provide City with any waste manifest. Services Provided by City at no Cost to Contractor: 1. Trash bins and disposal of screenings 2. Non-potable water for cleaning 3. Electrical power 4. Dump location for sludge material 5. Sufficient staging area for Contractors equipment Digester Specifications The digesters treat sludge from the primary flotation clarifiers and thickened sludge from secondary clarifiers. In order of process, the sludge is pumped to the acid phase digester, transferred to a methane phase digester and gravity flows to the secondary digester. Finally, the digested sludge is periodically pumped to one (1) of the twenty-four (24) concrete-lined drying beds. All acid and methane phase digesters have fixed covers and utilize sludge re-recirculation pumps used in conjunction with spiral tube heat exchangers. The heat exchangers are fed hot water through hot water circulating pumps. The sludge circulating pumps are set up to take sludge from the digesters and pump it through the heat exchangers. Digesters built before 1980 at the RWQCF utilize gas diffusers for mixing. Gas is injected into the digester through several diffusers located on the digester floor. These diffusers are arranged in a concentric pattern around the center of the digester. The remaining digesters use conventional mechanical mixing which injects the digester's content through several nozzles that promote circulation. Request for Information (RFI) should be directed to: purchasing@turlock.ca.us All questions must be in writing and received at least five (5) working days prior to the closing date for submittal of this Request for Proposal (RFP), to provide time for issuing and forwarding answers. The City will not be responsible for oral interpretations of the Request for Proposal (RFP).
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