SFJ 2/21 New

An innovative system was designed to provide for wastewater collection, treatment, disinfection, and reuse for a small residential development in California. The system combines the use of septic tanks, screened effluent filter vaults, high-head effluent pumps, small-diameter variable grade sewers, pressure sewers, a recirculating granular medium filter, an ultraviolet light disinfection unit, a subsurface drip irrigation system for wastewater reuse, and a community soil absorption field for winter-time disposal. The system has performed beyond required standards for wastewater reuse. groundwater, and elevated nitrate concentrations in groundwater, among other factors. In some cases, developers may not want to use septic systems because of the homeowners’ required involvement in keeping the systems operating properly. Where traditional septic systems are not appropriate or desired, small, decentralized community wastewater systems can be designed to collect, treat, and dispose of the wastewater generated from developments. The system considered in this paper is an example of a small community design that also provides for wastewater disinfection and reuse. Stonehurst is a 47-lot subdivision located near the city of Martinez in Contra Costa County, California, approximately 25 miles east of San Francisco. The subdivision is located in a hilly, rural area that did not have a wastewater collection system. An overall view of the rolling terrain is shown in photo 1. The use of conventional Stonehurst Development PHOTO 1 view of the rolling terrain at Stonehurst development, Contra Costa County, California