Groundwater well rehabilitation using hydropuls method: a case study in wonosobo groundwater well

Abstract

Abstract Hydropuls is one of the groundwater well rehabilitation methods that involves pulsing highly compressed nitrogen gas through screen pipes at an adjustable interval. Nitrogen gas was chosen because of its colorless, odorless, and inert properties. The aquifer lithology of this groundwater well is sand, gravel and breccias (member of Sundoro Volcanics; Qsu) with silty clay as the impermeable layer that makes the aquifer type is confined aquifer. The following methods were used in this well rehabilitation: step tests before, borehole camera before, hydropuls, airlifting, borehole camera after and step test after well rehabilitation. Thin section analysis shows that sediment mostly consists of lithic fragments and plagioclase. The results of the polished section analysis reveal that most of the metallic minerals are magnetite and hematite. The XRF results show that the sediment mostly consists of SiO2, Al2O3 and Fe2O3. According to the XRD results, the sediment is mostly albite. The interpretation of sediment analysis shows that the clogging is caused by iron precipitation. The result is an average increase in specific capacity of 1.43 l/s/m (a 168% increase over the initial conditions) and an average drawdown improvement of 2.56 m (a 114% improvement compared to pre-hydropuls conditions). Borehole camera imaging confirmed that the precipitation on the screen was removed and the screen is in good condition.