ETWD Recycling Plant

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 county.

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.

Regional Projects

The District participates in ongoing regional biosolids and recycled water treatment projects through membership in the South Orange County Wastewater Authority (SOCWA). The Regional Treatment 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

The District's most recent improvement was 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.
  • Increased recycled water pumping capacity.
  • Complete redundancy in power supply.
  • Automated monitoring and control.
  • Mechanical and electrical facilities.

Treatment Process

Headworks Preliminary Treatment
The wastewater treatment process involves several steps. The incoming wastewater enters the bar screens 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 futher tratment.

Equalization Influent Pump Station
The equalization basins provide temporary storage of wastewater when the incoming flow exceeds the average daily flow. Wastewater is pumped back into the flow stream during low flow periods of the day. The equalized flow enhances the overall treatment process.

Secondary Treatment
Air is continuously injected into the wastewater at 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 solid is returned to the aeration basins and the excess is removed for disposal.

Water Recycling
Water recycling consists of disinfecting and filtering the secondary effluent. Sodium Hypochlorite is added to kill harmful organisms. The secondary effluent is then passed through filters to remove suspended solids. The disinfected and filtered recycled water is delivered to restricted use areas, such as the Leisure World Golf Course, Nursery and Tennis Center, for irrigation purposes.

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.

Proposed Tertiary Treatment
The District is positioned for future tertiary treatment which will provide expanded water recycling on a local and regional basis. Tertiary treatment uses multimedia filtration and chemical addition for further polishing and removal of viruses and minute suspended solids. Tertiary treated water is less restrictive and can be used more extensively for commercial and public applications.

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