Benefits
The need for dramatic water conservation measures in the Las Vegas region led the Animal Foundation to seek a means to collect wastewater generated from the facility (especially kennel wash down drainage) treat it, and reuse it for wash down and other appropriate uses. The Living Machine® system allowed the RAC to meet its goal of significantly reducing water and energy use, while providing safe treatment of wastewater. With minimal operator attention, the Living Machine® system supplies the volume of reuse water needed for the increased number of kennels and runs for the dogs. In addition, the Living Machine® system provides opportunities for public education and interaction, showcasing a water reuse system with broad applications in water short areas.
In 2005, the Animal foundation, located in Las Vegas Nevada, significantly expanded its animal holding and adoption facilities at the Regional Animal Campus (RAC). The increased number of kennels and runs for the dogs require up to 10,000 gallons per day (gpd) of water for wash down. As part of an overall sustainable design approach, wastewater generated by the RAC is treated by a Tidal Flow Wetland Living Machine® system and reused for kennel wash down and other appropriate uses. The RAC Living Machine® system meets the stringent requirements of wastewater treatment mandated by the Nevada Department of Environmental Protection and can clean up to 10,000 gpd of wastewater. The Living Machine® system was chosen for its low energy usage and low operating and maintenance requirements.
At maximum loading, wastewater flow rates for wash down from the kennels vary between 5,000 and 10,000 gpd. The wastewater strength is fairly high and the process of washing kennels generates a high volume of wastewater in a very short time, usually 2 hours. This type of flow pattern would cause problems for most treatment processes, including passive settling tanks. Our Living Machine® system engineers knew that equalizing this flow to allow the treatment system components to function properly was critical and designed an equalization tank to spreadthe flow over a period of 18 to 20 hours.
Wastewater from a variety of RAC sources, including kennel and veterinary room wash down, cooler blow down, and domestic facilities, is collected in a 22,000 gallon primary equalization tank. The wastewater is then pumped through a 20,000 gallon final settling tank prior to treatment by the Living Machine® system. Effluent from the primary tank is pumped into an outdoor Tidal Wetland Living Machine® system that consists of six watertight basins containing subsurface plumbing, gravel-like media, and an assortment of plantings. Thin films of beneficial microorganisms grow on the surface of the treatment media. The Living Machine® tidal wetland cells go through “fill and drain” cycles. The draining process allows oxygen to flood the basins providing ample nitrification of the wastewater. Treated effluent from the tidal wetland cells is disinfected and polished by ozone injection, ultraviolet light, and a tablet chlorinator system. Polished water is pumped into a 30,000 gallon reuse holding tank, where water is stored until it is used as facility wash down water in outdoor animal holding areas.