Feasibility of low concentration diazinon treatment in large municipal wastewater treatment plant secondary effluent

During a series of whole effluent toxicity test (WET), diazinon was identified as a source of potential toxicity. Diazinon is specifically excluded from application to golf courses which are the primary user of reuse water. The City of Hollywood Southern Regional Wastewater Treatment Plant (WWTP) secondary effluent is beneficially reused as irrigation water, so the concerns regarding the low concentrations of diazinon must be resolved. One approach to resolving these concerns is to provide for additional treatment to reduce diazinon to below concentrations of concern. The available published information (see References) regarding treatment of diazinon is limited to treatment of spills and addresses much higher concentrations of the material than those present in the City of Hollywood effluent. T his paper reviews the available treatment alternatives and recommends bench testing of the three alternatives with the greatest potential for an effective and economical treatment. The recommended alternatives art high pH(12)hydrolysis, reaction with the target enzyme acetyl choline esterase, and hydrolysis catalyzed by a proprietary enzyme parathion hydrolase.