Treatment Process Optimization to ReduceDisinfection Byproduct Formation Potential: A Bench Scale Evaluation

摘要

According to the Stage 1 Disinfection Byproduct Rule (DBP), utilitiesrnmust comply with a THM maximum contaminant level (MCL) of 0.080rnmg/L and a HAA MCL of 0.060 mg/L. The formation of THMs andrnHAAs are impacted by total organic carbon, bromide, pH, temperature,rnchlorine dose, and contact time. As the elevation of Lake Mead continuesrnto decrease due to drought, these water quality parameters will result inrnchanges more conducive to forming THMs and HAAs potentially near thernMCL. The current regulations coupled with water quality changes havernprompted the Southern Nevada Water Authority (SNWA) to investigaternvarious strategies to reduce THM and HAA concentrations. Bench scalernexperiments were performed to identify ways to optimize the currentrntreatment plant performance without a major capital improvement.rnResults showed ozonation reduced THM concentrations 4-7% at a 1.0-logrnCryptosporidium inactivation, and 7-17% at a 2.0-log Cryptosporidiumrninactivation. Biological filtration did not provide any substantial THM (