Recycled Water Quality

A Proven Safety Record

California has been safely using treated recycled water since 1929. There has not been one confirmed case of anyone becoming ill from the proper use of recycled water for landscape or agricultural irrigation, or industrial use. Public health experts, pediatricians, specialists, leaders in the medical community, and virtually all of the credible scientific evidence available agree that irrigation is a safe use for recycled water.

The California Department of Health Services (DHS) and the California Regional Water Quality Control Board carefully regulate the treatment and use of recycled water. These agencies create and enforce some of the strictest water quality regulations in the world. They govern production, transmission and use, as well as the prevention of runoff and cross connections between drinking water and recycled water systems.

Recycled water is being safely and successfully used in this state to irrigate parks, playgrounds, school fields, wildlife habitat, recreation areas and landscaping. It is also used for toilet flushing, fire suppression and in industrial processing in some California cities. Farmers use recycled water to irrigate at least 20 varieties of food crops, including grapes, strawberries, lettuce and celery. Though recycled water usage in residential front and backyard irrigation is just starting to catch on in California, in states such as Arizona, Florida and Texas, it has been in use for many years.

The South Bayside System Authority

Redwood City’s wastewater is processed and treated at the South Bayside System Authority (SBSA) plant, located on the eastern edge of Redwood Shores. By the time recycled water is available for landscape irrigation, the SBSA will have completed the system upgrades necessary to provide its customers with high-quality tertiary-treated recycled water that meets or exceeds the DHS’ most stringent requirements for recycled water (Title 22).

In accordance with Title 22 requirements:

• The SBSA recycled water plant will provide the highest possible degree of treatment and disinfection.
• Recycled water will be delivered through purple pipes that are completely separate from drinking water pipes.
• Routine inspections will be conducted to ensure no cross-connection between drinking water pipes and recycled water pipes has occurred.
• A sophisticated computerized control system and a staff of state-certified system operators will continuously monitor the water recycling plant and water distribution system.

The Treatment Process

After entering the plant, wastewater from homes and businesses undergoes a carefully regulated purification and disinfection process to produce tertiary-treated recycled water. This means the wastewater that comes into the treatment plant is put through a multi-step treatment process before being distributed to customers for irrigation purposes:

Primary Sedimentation

Incoming wastewater slowly flows through the primary sedimentation tanks where settling and skimming removes solids and floating grease and sediment.

Biological Treatment

Next, the wastewater passes through a series of fixed film reactors, aeration basins and secondary clarifiers. Here naturally occurring microorganisms consume the dissolved organics, causing the microorganisms to fatten and grow heavy, making them easier to remove. Biological treatment removes approximately 90 to 95 percent of the remaining solids and biodegradable material from the wastewater.

Filtration and Disinfection

Finally, filtration removes any remaining solids and a disinfectant, such as chlorine, is used to destroy bacteria, viruses and other pathogens. Higher levels of disinfection are applied to water that is to be used for landscape irrigation or industrial processing.

Award-Winning Treatment Plant

In 1996 and 2001 the California Water Environment Association (CWEA) named SBSA the California “Plant of the Year” for several technical achievements, operations and innovations. SBSA achieved that recognition, out of 1,400 wastewater treatment facilities in California, primarily because it empowers all employees to participate in the key decisions that affect operations of the facility. CWEA has also bestowed numerous honors to individual SBSA employees over the years. And SBSA has been recognized for its creative outreach program with the community, environmental groups, business leaders, and government leaders during the public input process for the plant’s successful expansion to 29 million gallons per day (mgd).

The recycled water will be tested at every stage of treatment