About Your Wastewater Treatment Facility

Project Background

The Hi-Desert Water District (District) has constructed a Wastewater Treatment Facility (Facility) and wastewater collection system to service the residents of the Town of Yucca Valley (Town) and unincorporated area of San Bernardino County. The Facility is located at 58950 Sunnyslope Drive in Yucca Valley, California.
  • This project was necessary because the District's primary water source, groundwater from the Warren sub-basin of the Morongo Groundwater Basin (Basin), has seen significant increases in nitrate concentrations, according to a long-term monitoring program conducted by the United States Geological Survey (USGS).
  • In a 2003 study, USGS reported the primary cause of nitrate pollution in the Basin was septic tank effluent from households, commercials, and industrial facilities within (and surrounding) the Town.
  • In 2007, the Regional Board adopted a resolution (Resolution R7-2011-0004) identifying the Town as a top priority for eliminating the use of septic systems.
  • Resolution R7-2011-0004 led to an amendment to the Regional Board's Water Quality Control Plan (Basin Plan) which was adopted on May 19, 2011 and imposed a three-phased septic tank prohibition on new and existing septic systems within the Town.
  • In 2014, residents approved Assessment District 2014-1 which funded Clean Water State Revolving Fund (CWSRF) Project No. 5295-10.  This Project included construction and implementation of the Facility, installation of approximately 77 miles of sewer collection station, and construction and implementation of three sewer pump stations (Barron, Paxton and Kickapoo).

Construction and Implementation

As a primary component of its Wastewater Reclamation Project (Project), the District constructed and implemented a Wastewater Reclamation Facility (Facility) within the Town.
  • The Project was delivered via a progressive design-build method, in which a single Design-Builder was responsible for the development of the design, construction, and startup/commissioning of the Facility.
  • The District issued Notice to Proceed to W.M. Lyles Company and Kennedy Jenks (the Design-Builder) on January 16, 2018.
  • Construction activities commenced on January 17, 2018.
  • The Design-Build team reached Substantial Completion on November 4, 2019.
  • The Design-Build team completed clean water testing of the Facility in November 2019.
  • The Facility began receiving domestic effluent on November 6, 2019.
  • The Design-Build team reached Final Completion in February 2020.
  • The Facility began discharging clean water into its three (3) percolation ponds on February 18, 2020.

Wastewater Treatment Process Facilities

The Facility utilizes a membrane bioreactor (MBR) system as the main process for wastewater treatment.
  • The MBR is a combined biological and filtration process, and serves as the location of denitrification and suspended solids removal.
  • In addition to the MBR, the process treatment facilities also include preliminary treatment, accomplished through both coarse and fine screens and a grit removal chamber, UV disinfection for pathogen inactivation, a solids handling facility, and odor control facilities.

Facility Process Facilities Overview

Facility Treatment Major Process Equipment
Influent Pump Station and
Flow Equalization (EQ) Tank
Preliminary - Coarse Screen
- Washer/Compactor
- Influent Pumps
- Flow EQ Pumps
Find Screening and Grit Facility Preliminary - Grit Chamber
- Grit Decanter
- Fine Screen
- Washer/Compactor
Aeration and MBR Facility Biological Treatment and Filtration - Aeration Diffusers
- Process and MBR Air Blowers
- Submersible Mixers
- Membrane Cassettes
- RAS Pumps
- Foam/WAS Pumps
- Permeate Pumps
Ultraviolet Disinfection Disinfection Ultraviolet Reactors
Plant Water Pump Station Plant Effluent Distribution - Back Pulse Tank
- Plant Water Tank
- Recycled Water Tank
- Recycled Water Pumps
Percolation Ponds Groundwater Replenishment   
Chemical Feed and Storage Area Chemical Dosing - Sodium Hypochlorite Feed System
- Magnesium Hydroxide Feed System
- Activated Carbon Feed System
- Citric Acid Feed System
Sludge Storage Tank Solids Handling - Sludge Holding Tank Blowers
- Aeration Diffusers
- Decant Mechanism
- Screw Press Feed Pumps
Dewatering Building Solids Handling - Screw Presses
- Screw Conveyors
- Polymer Feed System
Odor Control Odor Control - Odor Control Blowers
- Biofilters

Monitoring and Reporting

To ensure the source control program and Wastewater Reclamation Facility (Facility) treatment processes are operating efficiently, the District monitors and reports primary and secondary MCLs, wastewater quality, and groundwater quality in accordance with Regional Water Quality Control Board (Regional Board) and Division of Drinking Water (DDW) requirements.
  • The water quality at the Facility will be monitored and reported at specific time intervals, as required by the Regional Board.
  • Steams to be monitored include influent, effluent, domestic water, groundwater, and sludge.
  • Monitoring and reporting intervals are set forth by the Regional Board via Board Order R7-2015-0043.

Next Steps ...

Throughout Phases 1, 2 and 3 of the District's Wastewater Reclamation Project (Project) recycled water will be replenished into an isolated portion of the Warren Valley sub-basin, where it will be retained underground for a minimum of five (5) years.
  • After a minimum of five (5) years, and depending on the rate at which the basin is filling, the District plans to construct an extraction well to withdraw a portion of the water and replenish the drinking water aquifer in the western portion of the sub-basin.
  • The extracted water will be transferred to one or more existing spreading basins in the western portion of the Warren Valley sub-basin that are located about existing drinking water aquifers, where it will be replenished a second time. These basins currently receive imported State Water Project (SWP) water for replenishing the drinking water aquifers.
  • When extraction begins, the District will monitor the quality of the extracted water as required by the Regional Water Quality Control Board (Regional Board).