SCH Number 2022120090

Project Info

Title

Wastewater Treatment Plant Improvements Project

Description

Existing Facilities. The existing Buttonwillow WWTP consists of two side pre-engineered modular biological treatment systems constructed in 2010. The modular units are constructed of painted steel and sit on a concrete slab and are entirely above grade. The primary components include an equalization tank, rotating biological contactor, Bio-wheel followed by a flat plate membrane filtration system designed to remove biochemical oxygen demand (BOD) and suspended solids. The system is also designed to nitrify/denitrify. Effluent from the membranes is distributed to one of two unlined recycled water ponds. These ponds provide for percolation of the effluent into the soil and sediments beneath the ponds and evaporation to the atmosphere. Effluent from the ponds may also be applied, if needed, to feed and fodder crops on the 40 acres adjacent to the WWTP, but the District has not used this disposal method in recent years. At the current flow of wastewater to the WWTP (0.091 MGD), effluent entering the ponds percolates and evaporates quickly, leaving little or no water available for irrigation. Proposed Facilities. The primary focus in the Project Report is the evaluation and selection of a treatment alternative to prevent future discharges that are out of compliance with the 2009 Waste Discharge Requirements. According to the Report, the existing WWTP has been plagued with operational issues since it was commissioned in 2010. Due to operational issues, the WWTP has consistently been out of compliance with the WDR limits. In short, the WWTP has not operated as originally designed and this has resulted in secondary treatment capacity not being used and discharge requirements, such as Total Suspended Solids (TSS), Electrical Conductivity (EC), and Total Nitrogen. The net effect of this situation is that the existing WWTP needs to be upgraded or an alternative treatment system needs to be installed. After evaluating four alternatives in the Project Report, Alternative 2, the Biolac Extended Aeration System, was selected as the recommended alternative for treatment and disposal. The Biolac System can meet the nitrogen disposal requirements and eliminates the acquisition of additional crop land and access to supplemental irrigation water.

2 documents in project