AWWA JAW3854

Groundwater recharge with tertiary effluent via spreading basins is practiced in the Dan region project for indirect reuse of municipal wastewater from the Tel Aviv metropolitan area. A comprehensive monitoring program accompanies the full-scale recharge operation. The chloride ion is a reliable tracer of the recharged effluent in the aquifer. The effluent quality is substantially improved by passage through both the unsaturated zone and the calcareous sandstone aquifer, particularly with respect to organic matter, phosphorus, chemical stability, sodium adsorption ratio, and several trace elements. In addition to effluent treatment, groundwater recharge provides seasonal and multiannual storage, offers economical as well as psychological benefits, and enhances the reliability of the reclamation system. Includes 10 references, tables, figures.