Project Description
The City of Bakersfield retained Parsons to provide engineering services for planning, design, and construction support for expansion of their 16 mgd Wastewater Treatment Plant No. 3 to 32 mgd capacity with 2 mgd tertiary treatment capabilities.
This project included optimization of existing facilities and site master plan for ultimate 64 mgd capacity.
It is anticipated that 14 mgd of secondary effluent will continue to flow to the Green Acres Farm west of the City for reuse and that 16 mgd will be percolated on site. The remaining 2 mgd will receive tertiary treatment (Title 22) and be reused locally for in-plant use and landscape and turf irrigation.
The facilities being designed are as follows:
- Replacement of an existing off site pump station with a new 40-mgd unit and a new discharge sewer to convey the wastewater to the treatment plant
- A new headworks that includes facilities for screening of the treatment plant's influent wastewater, pumping the wastewater flow to two vortex type grit removal tanks, washing and dewatering of the collected screenings and grit, as well as structures for distributing the flow to the primary clarifiers
- Conversion of four existing secondary clarifiers into primary clarifiers to work with the four existing primary clarifiers
- Conversion of two existing trickling filters into new organic media biofilters
- New aeration tanks and secondary clarifiers together with return and waste activated sludge pumping systems for BOD and nitrogen removal
- New percolation basins for disposal of treated wastewater
- 2 mgd tertiary treatment including filtration and disinfection
- Conversion of two existing trickling filters into new reclaimed water storage reservoirs
- Reclaimed water pump station for in-plant use and landscape and turf irrigation
- Two dissolved air floatation units for thickening of secondary sludge
- An upgraded boiler/heat exchanger system to augment the heating capacity of the existing six anaerobic sludge digesters
- Two new fixed cover anaerobic digesters to increase the plant's solids processing capacity
- A new sludge dewatering system to house several centrifuges, sludge cake pump facilities, and truck loading facilities
- A new cogeneration system for using the digester gas to generate electrical power
- A new odor control system that includes a total of three odor removal biofilters (two converted trickling filters and one completely new biofilter unit)
Parsons’ original scope of work involved the addition of an 8 mgd activated sludge/solids contact system to the existing trickling filter plant. Following meetings with the City and Central Valley RWQCB, the scope was expanded to double the size of the plant expansion, include tertiary filtration and disinfection for at least 2 mgd of the plant’s flow, and evaluate the need for nitrogen removal through nitrification and denitrification.
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