THE RISK IMPACT OF CLASS I INJECTION WELLSON ASR WELLS

摘要

There are four primary alternatives for disposing municipal wastewater effluent in southeast Florida. Injection of wastewater treatment plant effluent into deep wells is currently one of those options. In Miami-Dade County it has been a part of the waste disposal system for over 30 years. In the past several years, elevated concentrations of ammonia along with depressed salinity relative to native water in the Floridan aquifer, have been reported in monitoring wells in zones overlying the injection zone at the South County wastewater treatment facility in Miami-Dade County. This finding has raised concerns of the U.S. EPA and others regarding the extent of migration of injected water. An investigation undertaken by the University of Miami evaluated the relative risk of injection well disposal versus the two other options permitted in South Florida: surface water discharges and ocean outfalls. That study gathered water quality data, relative to disposal of wastewater treatment plant effluent was gathered, along with water quality data on the receiving waters, from utilities. The results indicated that health risks associated with deep wells were generally lower than those of the other two alternatives, and that the proximity of injection wells to aquifer storage and recovery wells was found to determine the primary injection well risk. Additional data collection and analysis were recommended to understand that statistical monitoring of effluents for nitrosamines and pharmaceutically active substances be implemented on a broad scale.