EWA’s mission statement commits the organization to “maximizing the use of alternative and renewable resources.”  EWA demonstrates this commitment through implementation of technologies that allow for the beneficial use of wastewater by-products.  Technologies currently in use are described below.

Water Recycling
Water conservation is key to ensuring water reliability for the San Diego Region. There are three water reclamation plants operating in EWA’s service area that produce water used for irrigation purposes. These plants have the capacity to recycle 10 million gallons of water per day,  which represents about one-third of the wastewater produced in the service area. Click here to read more.

Energy Recovery  EWA generates over 60% of the electricity needed to operate the treatment plant through use of its cogeneration facility.  This facility converts methane gas (produced by the wastewater treatment process) into electricity and also produces thermal energy used to reduce natural gas purchases.  Operation of the cogeneration facility reduces EWA’s energy costs by about $2 million per year. Click here to read more.

Biosolids Reuse Solids generated from the wastewater treatment process are dewatered using centrifuges and a heat dryer.  This converts the material into Class A biosolids pellets that are used as a biofuel or fertilizer product.  Implementation of the heat dryer technology has reduced EWA’s costs for biosolids disposal by about $2 million per year. Click here to read more.

Phosphorus Recovery
Influent wastewater to the Encina Water Pollution Control Facility (EWPCF) contains valuable plant nutrients.  Three are of particular interest: phosphorus and nitrogen (as ammonium), which are primary plant macronutrients, and magnesium, which is a secondary macronutrient.  In the wastewater treatment process, these three nutrients combine to form struvite which precipitates as a white crystalline substance.  This material can result in increased equipment maintenance, but can also potentially be recovered and used as a source of phosphorus in commercial fertilizers. EWA conducted a pilot study for phosphorus recovery in early 2011 and is evaluating the cost-effectiveness of this process. Check back on this web page for future updates on the phosphorus recovery effort.

RenEWAble News
EWA publishes a semiannual e-bulletin entitled RenEWAble News, which provides updates on the implementation of new technologies.  To subscribe click on the following link.