What is Recycled Water?
Recycled water is defined in the California Water Code as “…water which, as a result of treatment of waste, is suitable for a direct beneficial use or a controlled use that would not otherwise occur and is therefore considered a valuable resource. Basically, recycled water is highly treated wastewater that is reused for purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, or replenishing groundwater basins.
Are there different types of Recycled Water?
Yes, there are different types of recycled water based on the level of treatment the water has gone through. The state regulates how recycled water can be used based on the level of treatment.
Recycled wastewater undergoes primary, secondary and tertiary treatment at water reclamation plants. During primary treatment, large solids are removed. Secondary treatment uses bacteria to remove approximately 90% to 95% of the remaining solids and uses a disinfectant, such as chlorine, to destroy bacteria, viruses, and other pathogens. For some reuse applications, advanced tertiary treatment processes, such as filtration or reverse osmosis, are required. The treatment processes duplicate and accelerate nature’s own purifying actions.
Tertiary treated recycled water, often called Title 22 water, can be used for a wide variety of non-potable uses including all types of irrigation, toilet flushing, and industrial processes. IRWD produces and distributes disinfected, tertiary treated recycled water.
Advanced treated recycled water utilizes new technology to produce purified recycled water that can be used for groundwater recharge. Locally, the Orange County Water District is producing and using advanced treated recycled water from the Groundwater Replenishment System to supplement water supplies in the Orange County Groundwater Basin.
What Is Purple Pipe?
Recycled water is delivered through a distribution system that is completely separate from the drinking water infrastructure. This separate system uses what is known internationally as “purple pipe” to keep these valuable sources of water separate and make the recycled water system easily identifiable. The use of purple pipe infrastructure helps to minimize cross-connections between the two systems.
How Does Recycled Water Differ from ‘Gray water’?
Recycled water is wastewater treated to approved levels for reuse for approved non-potable uses which are primarily landscape irrigation but can include industrial applications such as cooling tower make-up water. Graywater is defined in the California Water Code as “…untreated wastewater which has not been contaminated by any toilet discharge has not been affected by infectious, contaminated, or unhealthy bodily wastes, and which does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes. Graywater includes wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs but does not include wastewater from kitchen sinks or dishwashers.”
Graywater can only be used to irrigate landscaping at the site from which the graywater is generated and can only be done using a subsurface irrigation system.