Converting Discharge from Surface Water to Land Disposal Method
The City of Biggs Wastewater Treatment Plant (WWTP) was in violation of their National Pollutant Discharge Elimination System (NPDES) Permit. A Time Schedule Order (TSO) was approved to allow the city time to develop and implement methods of compliance and construct the necessary improvements to convert the plant from a surface water discharge to a land disposal application.
Revised Final Study
Bennett Engineering Services was selected to prepare a revision to a previously completed Planning Study. This Revised Final Study proposed a land disposal alternative that maintains the existing level of treatment and disinfection, eliminates surface discharge to waters of the U.S., and provides seasonal storage for dry weather irrigation. It also allows the city comply with permitting requirements.
Subsequently, the team was selected to prepare a design to convert their existing Wastewater Treatment Plant (WWTP) from a surface water discharge facility to a land application discharge facility. To best serve the city the conversion was designed in two phases. The Phase 1 portion consisted of plant upgrades and the rehabilitation of existing facilities to ready the existing WWTP while the land acquisition and environmental processes were underway for Phase 2.
Phase 1 design consists of a new influent pump station, a new influent screen to remove large debris and plastics, improvements to the rock filters to reduce mosquitoes, improvements to the chlorine distribution system, updated electrical power and controls, and updates to the operations/laboratory building.
Phase 2 includes the acquisition of approximately 150 acres of land to irrigate, grading and drainage of the crop fields and storage pond, field irrigation piping design, a pump station to transport water to the storage pond, and updates to the electrical and controls.
The upgrades to the Biggs Wastewater Treatment Plant allows the city to be in compliance with the Waste Discharge Requirements (WDR) Permit and will serve as a stabilizing influence to the community as questions about the longer-term uncertainties of discharge permit requirements will be eliminated. It also provides positive environmental and economic impacts to members of the community through the enhancement of the physical environment resulting from the discharge of cleaner waters and by providing reduced fiscal impacts to lower-income households resulting from expensive treatment plant upgrade requirements in the future.
The WWTP upgrades eliminated costly future plant upgrades thereby keeping utility bills manageable and making the city more competitive in the local economic market by reducing the potential for utility cost uncertainties.