If drought hits or imported sources are reduced we will face a serious water crisis unless we begin looking at innovative ways to secure alternative and new sources of water. An area of intensive research and real world reuse is recycled water. With greater education and understanding, people are much more accepting of recycled water as an important water supply solution for the future. There are a variety of “types” of recycled water – we will discuss indirect potable reuse and greywater.
The benefits of recycled water include:
- lower fresh water use
- reliable, high-quality water to replenish the groundwater basin, to protect the groundwater basin from seawater intrusion, and for industrial uses
- decreased reliance on imported water from northern California and the Colorado River
- local control
- reduced amount of treated wastewater released into the ocean
- less strain on septic tanks or treatment plants
- less energy and chemical use
- enhanced environmental awareness and sensitivity among residents
Recycled Water – Indirect Potable Reuse
One form of recycled or reclaimed water is former wastewater (sewage) that has been treated to remove solids and certain impurities. Recycled or reclaimed water may be pumped into (subsurface recharge) or percolated down to (surface recharge) groundwater aquifers, pumped out, treated again, and finally used as drinking water. This technique may also be referred to as groundwater recharging. This recharging is often done by using the treated wastewater for irrigation. In most locations, it is only intended to be used for non-potable uses such as irrigation, dust control, and fire suppression.
In some locations, including Orange County, wastewater is given more advanced treatment and is used indirectly for drinking. Orange County's Groundwater Replenishment System takes highly treated sewer water and purifies it to levels that meet state and federal drinking water standards - as pure as bottled water. It uses a three-step process that includes reverse osmosis, which is used by manufacturers of bottled water, as well as micro-filtration and ultraviolet light and hydrogen peroxide advanced oxidation treatment. Once purified, the water is sent to spreading basins. The newly purified water seeps into the ground, like rain, and blends with groundwater.
G.R.I.P., which stands for Groundwater Reliability Improvement Program, involves the following organizations:
- Upper Area: Upper San Gabriel Valley Municipal Water District (Upper District) with the San Gabriel Valley Municipal Water District (SGVMWD)
- Lower Area: Water Replenishment District of Southern California (WRD)
- Los Angeles County Sanitation Districts (LACSD)
The basic project concept is to obtain recycled water supply from the San Jose Creek Water Reclamation Plant (SJCWRP) which is operated by the LACSD.
Recycled Water - Greywater
Greywater is all the non-toilet wastewater produced in the average household including the water from bathtubs, showers, sinks, washing machines, and dishwashers. Such water comprises 50-80% of residential "waste" water. This may be reused for other purposes, especially landscape irrigation. Although greywater does not need extensive chemical or biological treatment before it can be used in the garden as irrigation water, it still must be used carefully because it usually contains common contaminants such as soap, grease, hair, detergent, cosmetics, and food particles.