Water Recycling Plant

Front of El Toro Water District Building
The El Toro Water District Water Recycling Plant (WRP) is located in South Orange County serving portions of the cities of Laguna Hills, Mission Viejo, Aliso Viejo, Lake Forest and all of the City of Laguna Woods. Governed by a five member Board of Directors elected at large, the District develops and implements policies that meet the short and long range economic, water resource and environmental goals of its customers and the region.

The WRP is one of the oldest water recycling plants in Orange County. Production and delivery of recycled water for golf course irrigation has existed since the WRP’s inception in 1963, at which time the District served a total population of about 125 on 4,750 acres of land. Groundwater supplies were adequate to meet the moderate domestic and agricultural demand of the community at the time.

El Toro Water District’s population has increased to 51,000. The District has been able to meet its water demands from a combination of water resources and technology that optimally promote use of water conservation practices, water importation and recycled water treatment and delivery.

The District participates in ongoing regional biosolids and recycled water projects through membership in the South Orange County Wastewater Authority (SOCWA). The Regional Treatment Plant facilities are located in the city of Laguna Niguel adjacent to the Regional Park. The regional partnerships between neighboring sister agencies and regulatory entities provide an economic, environmentally sensitive and efficient regional mechanism for effluent disposal, biosolids recycling, and expanded and new recycled water markets to serve South County customers within and outside our service area boundary.

Major Reconstruction

In 1998, the District’s completed a major reconstruction and upgrade project of plant process components. The project’s goals were to meet anticipated regulatory requirements, improve effluent and recycled water quality, accommodate changes in wastewater characteristics due to water conservation and position the District to expand the use of recycled water locally and regionally. The project achieved its objectives of compliance with short and long term regulatory requirements, while providing higher effluent and recycled water quality.

Process Enhancements

  • High efficiency aeration to reduce energy costs and improve oxygen transfer efficiency.
  • Innovative soil scrubber technology to control odors.
  • Flow equalization to improve treatment control and reduce energy consumption.
  • Complete redundancy in power supply.
  • Automated monitoring and control.
  • Mechanical and electrical facilities.

Treatment Process

Water Recycling Pipes

Headworks Preliminary Treatment

The wastewater treatment process involves several steps. The incoming wastewater enters the bar screen where large objects are removed that could create problems for the downstream processes. It then flows into the grit chamber where the heaviest materials settle out and are hauled to a regulated landfill. Fine screens then remove coarse organic materials for further treatment.

Equalization Influent Pump Station

The equalization basins provide temporary storage of wastewater when the incoming flow exceeds the average daily flow. Wastewater is consistently pumped back into the flow stream to maintain a steady, equalized flow through the secondary treatment process. The equalized flow enhances the overall treatment process.

Secondary Treatment

Air is continuously injected into the wastewater in the aeration basins, which fosters the growth of microorganisms that consume organic material in the wastewater. The cultivated microorganisms eventually settle out as solids in the secondary clarifiers. A portion of the settled solids is returned to the aeration basins and the excess is removed for disposal.

Solids Disposal

Solids produced during various stages of treatment are thickened and trucked to the SOCWA facilities. Organic matter in the solids is stablilized in the digesters. The digested solids are dewatered and conveyed offsite for biosolids recycling. Methane gas, a by-product of digestion, is piped to the Cogeneration Building to fuel generators that supplement the plant’s power needs.

Tertiary Treatment – Water Recycling

Water recycling consists of disinfecting and filtering the secondary effluent producing recycled water suitable for use for landscape irrigation.  Tertiary treatment is an additional filtration process that follows the current primary and secondary treatment processes. Tertiary treatment provides expanded water recycling on a local and regional basis.

In 2012, the District began a Recycled Water Expansion Project to increase the treatment and delivery of recycled water through a new tertiary treatment facility.  Simultaneously, the District built a new recycled water distribution system that included 100,000 feet of recycled water pipelines beneath the roadways in portions of Laguna Woods and the northwest portion of Laguna Hills.  This distribution system is completely separate from the drinking water distribution system and used for irrigation purposes only.

The tertiary treatment plant is designed to produce as much as 3.7 million gallons per day with a peak hour pumping capacity of over 5,000 gallons per minute.  The plant was designed with the ability to expand capacity up to the expected maximum amount of raw wastewater entering the plant.

In the tertiary treatment process, secondary treated effluent flows through cloth media disc filters.  The cloth media traps solids and debris, while the filtered water flows into a basin where chlorine is injected for disinfection. Chlorine disinfection further polishes and removes viruses and pathogens.  The chlorine infused water travels through a series of baffled channels to ensure compliance with chlorine contact time requirements.  The tertiary treated water is then ready to be pumped into the recycled water irrigation distribution system.

The Recycled Water Expansion Project includes the conversion to recycled water over 200 dedicated irrigation meters in the cities of Laguna Woods and Laguna Hills.  The onsite retrofits are estimated to be complete by the middle of 2016.  After the conversions are complete, it will reduce the District’s imported potable water requirements by over 900 acre feet per year.  The total production, including the Laguna Woods Village golf course and certain uses here at the Water Recycling Plant will amount to over 1,400 acre feet per year.

The expanded system will significantly reduce the amount of treated wastewater discharged into the ocean and help reduce the greenhouse gasses that result from pumping water into the region.  This reduction in the dependence of imported water is a huge benefit to our communities and future generations in saving our most precious resource – Water!