Proactive Management of Water Quality in Aquifer Storage Transfer and Recovery

Abstract

This paper reports the status of an ongoing effort to ensure the quality of water produced at an Aquifer Storage Transfer and Recovery (ASTR) site in South Korea. ASTR is one of the managed aquifer recharge techniques in which water is intentionally recharged to suitable aquifers for subsequent recovery. Surface water injected to an aquifer is converted into water of drinkable quality by natural process. In an ASTR project being developed in the densely populated delta area of the Nakdong River basin, a new framework is being implemented in which water safety is addressed through the analysis and control of biological, chemical, and physical hazards from intake, pretreatment, injection and recovery, to distribution and consumption of water. The task is done by the incorporation of Hazard Analysis and Critical Control Point (HACCP) to the ASTR process. Originated from the food industry, HACCP identifies, evaluates, and controls hazards to ensure the safety of the product. Principles of HACCP were applied to the ASTR water production system. Hazard analysis revealed that most hazardous events were due to the chemicals transported in the basin. Risk assessment was conducted to identify the sources of chemicals which pose a potential threat to the water quality of the ASTR site. Such information will be valuable for the proactive management of chemicals at the basin scale. Critical control points (CCP) were determined by the decision tree method, and critical limits for water quality parameters at CCPs were established subsequently.