Wastewater Treatment Plant 3—2007 Expansion
Treatment Plant Had Reached Capacity Limits
The metropolitan Bakersfield area is located in the eastern portion of the southern San Joaquin Valley in central California, about 120 miles north of downtown Los Angeles. Bakersfield has been one of the fastest growing cities in California for many years, and it had a Year 2000 census of 246,889. Bakersfield expects that its population will continue to grow between 2% and 3% a year, resulting in a projected Year 2025 population increase to 507,500. Wastewater flows are expected to increase proportionally in Bakersfield’s service area.
Bakersfield currently owns and operates two wastewater treatment and disposal facilities. Wastewater Treatment Plant 2, serving the eastern half of the city, was expanded recently and has adequate capacity. However, Wastewater Treatment Plant 3, serving the western half, has not been upgraded in more than 10 years and has reached capacity.
Plant 3’s existing facilities provide treatment capabilities for both liquid and solid streams with an average daily flow capacity of 16 million gallons per day (mgd). At present, the liquid stream treatment facilities consist of one headworks, four primary clarifiers, four trickling filters, four secondary clarifiers, one overflow/equalization lagoon, and four storage reservoirs. For most of the year, the treated effluent is transported through an 8.5-mi-long, outfall line to Los Angeles’ Green Acres Farm, west of Interstate 5. During periods of wet weather, Plant 3 temporarily stores excess effluent that cannot be accepted by the farm. The solid stream treatment facilities consist of four primary and three secondary sludge pumps, six anaerobic digesters, and 24 sludge-drying beds. Trucks haul the dried sludge to the city-owned farm associated with Plant 2, where it is applied to the soil as a fertilizer supplement.