Wastewater

Collection System Description

Livingston operates its own wastewater collection system and domestic wastewater treatment plant. This collection system consists of approximately 29 miles of 6-inch through 27-inch diameter sewer pipe. Approximately half of this total consists of 8-inch sewer mains. The “backbone” of the system consists of sewer trunk lines, generally 10-inches in diameter and larger, that convey the wastewater flows to the Domestic Wastewater Treatment Plant. The largest sewer line is the 27-inch diameter Vinewood Avenue trunk line that terminates at the Domestic Wastewater Treatment Plant.

During dry weather conditions, the average dry weather day flow into the Domestic Wastewater Treatment Plant is 1.06 million gallons per day (mgd). Wet weather flow into the Domestic Wastewater Treatment Plant is currently 1.64 million gallons per day (mgd). Continued development in Livingston will increase the peak flow conveyed through the existing collection system. At build out, the average dry weather flow is projected to be 4.5 million gallons per day (mgd) and the average peak dry weather flow per day is projected to be 6.60 million gallons per day (mgd). Those segments of the existing collection system will need to be replaced in order to correct existing deficiencies and to accommodate growth.

There are nine lift stations in the collection system, the largest of which is the Highway 99 Lift Station. The Highway 99 Lift Station pumps wastewater collected from the east side of Highway 99, and discharges it on the west side of the highway into the Vinewood sewer trunk line near the intersection of First Street and B Street. Four of the nine sewer lift stations are located east of Highway 99 and five are located south of Highway 99. The pumping capacity of the existing lift stations ranges from 3.34 million gallons per day (mgd) for the Highway 99 Lift Station to a low of 0.43 million gallons per day (mgd) at the Narada Way Lift Station.

Wastewater Collection System Master Plan

In 2007, the City Council approved a Wastewater Collection System Master Plan. This plan outlines (1) existing system conditions, (2) existing capacity deficiencies, and (3) proposed improvements to serve future growth. Future development will be served by new wastewater conveyance infrastructure including collectors, trunks and interceptor sewer lines and appurtenances. Expansion of the Domestic Wastewater Treatment Plant could occur entirely on the existing treatment plant property while percolation ponds required for the effluent discharge would need to be constructed outside the current treatment plant boundary.

Domestic Wastewater Treatment Plant

Livingston’s first domestic wastewater treatment facility was constructed in 1963. It consisted of screening, grit removal, primary clarification, anaerobic digestion, solar sludge drying, and six treatment/percolation ponds. In 2004, Livingston completed a $15.7 million upgrade to the facility that included a new oxidation ditch, two new secondary clarifiers, four new influent pumps, and a mechanical bar screen. The plant has been producing an excellent effluent consistently well below the effluent limits. The Biochemical Oxygen Demand, Total Suspended Solids, and nitrogen levels have all been less than 10 mg/l, or approximately 20 percent of the maximum allowable limits.

The existing Domestic Wastewater Treatment Plant has sufficient capacity to treat an average daily maximum month flow (ADMMF) of 2.0 million gallons per day (mgd). Wastewater flows could exceed the capacity of the existing treatment plant when the City’s population approaches 21,000 people. Under the terms of the Regional Water Quality Control Board (RWQCB) Order Number 89-066, Waste Discharge Requirement for the City of Livingston Wastewater Treatment Facility (April 28, 1989), the dry weather average 30-day flow cannot exceed 1.8 million gallons per day (mgd).

Groundwater Monitoring

The City also submitted a “Revised Groundwater Work Plan” (Condor Earth Technologies, July 2006) to the Regional Water Quality Control Board as required by WDR Order No. 89-066. The purpose of the work plan was to describe the groundwater monitoring program that will help identify and evaluate potential impacts to the groundwater quality resulting from the Domestic Wastewater Treatment Plant discharges. The work plan included an evaluation of groundwater elevation contour maps of the area as part of a mounding analysis. The evaluation indicated that the present regional groundwater gradient is to the southwest near the Domestic Wastewater Treatment Plant. The City’s consultant also prepared a groundwater elevation contour map based on measurements collected in February 2005. The contour map indicates there is a water table mound beneath the Domestic Wastewater Treatment Plant and that groundwater from the mound travels south.

The City is currently designing and completing the environmental document for expansion of the Domestic Wastewater Treatment Plant. This expansion will increase the capacity from 2.0 to 4.0 million gallons per day (mgd). The design includes a new headworks with odor control, a second oxidation ditch, two clarifiers, a centrifuge facility with odor control to replace the sludge drying beds, a ninth percolation pond, solids pump station, operations and maintenance buildings, and other support facilities for the treatment plant. The City has completed 90 percent of the engineering plans and 70 percent of the environmental document for the plant expansion. This expansion will provide the City with the ability to provide wastewater service to approximately 43,000 residents. All plant improvements will be constructed on the existing plant property. Please see site plan.

Industrial Wastewater Treatment Plant

The City also owns and operates an industrial wastewater treatment plant for treating wastewater generated solely from the Foster Farms poultry processing plant. This facility is located north of Bird Street on the south bank of the Merced River. The facility has been regulated by WDR Order No.79-209. The facility consists of two aerated treatment ponds followed by ten facultative treatment and percolation ponds. The surface ponds, comprising 83 acres, sit on 121 acres of property.

The poultry wastewater is pretreated at Foster Farms. The pretreatment process consists of fine screening, flow equalization, and dissolved air flotation thickening. The pre-treated wastewater flows by gravity via a 42-inch diameter sewer line from the poultry facility to the Livingston Industrial Wastewater Treatment Plant. The average daily flow from 2001 through 2006 was approximately 4.0 million gallons per day (mgd). This flow reflects when the poultry facility was operating, which was typically six days per week. A portion of the Industrial Wastewater Treatment Plant wastewater is reclaimed by irrigating privately owned property adjacent to the City property.

The Industrial Wastewater Treatment Plant process consists of two aerated ponds followed by ten unaerated treatment and percolation ponds. This plan operates under Waste Discharge Order 79-209 issued by the Regional Water Quality Control Board (RWQCB). Foster Farms, the owner of the 120-acre reclamation area, maintains a separate Water Reclamation Requirements Permit (WDR Order 93-091) for the application of treated wastewater to the reclamation area. This permit allows application of up to 2.40 million gallons per day (mgd) of final effluent to the reclamation area during the irrigation season.