CT Consultants performed an evaluation of impacts of the new phosphorus and potential total nitrogen limits on the City of Canton’s Water Reclamation Facility’s wet stream and solids stream. Included in the study was a review of plant process equipment and an assessment of equipment and infrastructure to determine cost effective improvements. The recommended improvements include the retrofit of the existing 39 mgd plant with a new preliminary treatment facility and membrane bioreactor (MBR) activated sludge to meet phosphorus and total nitrogren limits and increase capacity of the plant secondary treatment facility to 88 mgd.
The plant improvements include various modifications to the existing influent pump station, conversion of the existing detritus and preaeration tanks to a new preliminary treatment facility, converting the primary tanks to stage 1 equalization, converting the activated sludge process with nitrification to MBR activated sludge with BioP and BNR, conversion of the secondary tanks to stage 2 equalization, demolition of the tertiary treatment facility, elimination of disinfection and the addition of post aeration, sludge conditioning/stabilization, and modifications to the existing solids handling processes.
The new preliminary treatment facility will include longitudinal aerated grease and grit removal and fine screen (2 mm). The six existing activated sludge basins will be converted to new phosphorus removal, total nitrogen removal and membrane bioreactor activated sludge process units. The improvement will modify the six tanks with an anaerobic zone, an anoxic zone, an aeration zone and a membrane basin. Each membrane basin will include a lower gallery to accommodate air piping, chemical clean piping, permeate piping, and return activated sludge conveyance. All of the new wet stream improvements are being incorporated in existing structures.
The improvement will include a chemical feed system to trim phosphorus, a methanol chemical system to add carbon for total nitrogen removal and chemical system to clean in place the membranes.
The existing sludge thickeners will be modified for aerated sludge holding and continuous waste from the secondary treatment process and continuous feed to the existing belt filter presses. New pumps will be added at the solids holding tanks to feed directly to the belt filter presses and to eliminate two stage pumping to the presses. The incinerators will be demolished. Alternative solids handling facilities were evaluated however found to be cost prohibited when compared to landfill disposal of dewatered raw sludge. A new conveyance and load out facility is being added to load containers for hauling by an independent contractor.
The SCADA system is being upgrade and modified to remove eliminated treatment components and will include a new process controller for the membrane system at the operator’s office and the administration building control room.
Electrical improvements will include new or relocation of existing power distribution poles, conduit runs, transformers, switches, MCC’s and any other gear, wire/conduit runs for power and control to all equipment, lighting, receptacles, instruments and any other device requiring power whether it is new or the existing is modified or reused.