Effect of Flow Rate on Physical, Chemical, and Biological Clogging Processes in Column Flow-Through Experiments

This study investigates clogging at slower injection rates through laboratory column experiments and geochemical analyses. Clogging in recharge wells is a major concern for aquifer storage and recovery (ASR) systems. Many of the current methods used to predict recharge well clogging assume a rapid injection rate. These methods may not adequately identify the clogging processes occurring at slow flow rates.

Further understanding of clogging factors at slow flow rates will aid in the selection of the most beneficial redevelopment and pretreatment methods for new ASR technologies, such as an ongoing project at the Kansas Geologic Survey (KGS) investigating a low-cost alternative to traditional ASR systems. This project utilizes gravity-induced recharge and small-diameter wells installed with direct-push technology to recharge and store groundwater in an alluvial aquifer in the Lower Republican River basin, Kansas. The KGS ASR system will have significantly slower injection rates than common ASR wells due to increased frictional losses in small-diameter wells and the absence of injection pumps.

To examine clogging processes at slow flow rates, laboratory columns packed with sand and gravel cores taken from the Pleistocene Belleville formation during direct-push well installation at the Lower Republican River field site are used for clogging experiments. Changes in geochemistry, turbidity, and hydraulic conductivity are monitored in three column sets running at rates of 1 m/d, 2 m/day, and 3 m/day. Each column set contains three columns circulating one column each of sterilized surface water, native aquifer water, and treated surface water. After a 20-day period, flow is stopped and biomass is quantified with PLFA analysis.