Appropriate Degree of Domestic Wastewater Treatment Before Groundwater Recharge and for Shrubbery Irrigation

Considerable controversy exists today on the public health and environmental safety of "reclaimed " domestic wastewaters for reuse for groundwater recharge and ornamental shrubbery irrigation. In some areas such as California only secondary treatment is required by regulatory agencies before domestic wastewater reuse for some purposes. In other areas, treatment equivalent to that provided domestic water supplies and beyond is required/practiced, including ultrafiltration and reverse osmosis. Advocates of minimal treatment before reuse assert that the "risk " to public health and the environment is small compared to the cost of the additional treatment. Further, they rely on soil aquifer treatment to "remove " residual constituents from the domestic wastewaters that are recharged to groundwaters. It is now clear from studies conducted in various areas that pathogenic organisms (enteroviruses and protozoan cysts) and hazardous organics present in secondarily treated domestic wastewater are present in the "reclaimed " wastewater that are threats to public health and the environment. Further, the enteroviruses and some residual organics are being found to be transported in aquifer systems and therefore are