AWWA REUSE52082

Irvine Ranch Water District (IRWD) is located in Southern California and operates sewer collection, domestic and non-potable water distribution systems. The sewer collection system consists of four main tributary areas feeding the Michelson Water Reclamation Plan (MWRP). Although there are other sewer collection systems within IRWD's service area, those flows are diverted to other agencies. MWRP is IRWD's sole source of recycled water and delivers approximately 12,500 acre-feet of recycled water per year (approximately 13 million gallons per day) to the non-potable water distribution system. Although IRWD meets the Regional Water Quality Control Board's limits for the MWRP total dissolved solids (TDS) the majority of the time, residential self-regenerative (SR) water softeners could potentially increase TDS levels enough that IRWD would violate the permitted levels a majority of the time. This paper discusses IRWD's efforts to better understand the sources of increased TDS in the sewer collection systems. Includes 3 references, table.