The effectiveness of horizontal water filtering system on deep rainwater harvesting wells

Abstract

The main requirement in recharging aquifers is the quality of refill water must meet the groundwater quality standards. Therefore, the role of the filtration system is important. The horizontal water filtering system has designed to lengthen the filtering process. First step: Rainwater falls that contaminated with various substances flows into the 20 cm thick and 1 m depth of gravels; Second Step: Rainwater continued flowing into the horizontal pipe, 4” of diameter, 20 cm length, with the fibre palm tree inside. The filtered water comes out and collected in a reservoir, flows into a recharge wells with 4” diameter and 32 m depth, and fills the aquifer after going through the soil layer. Laboratory tests shows that the horizontal water filtering system is effective to reduce the content of substances, except the TDS for filtering system in Plaga Village. It decreased from 135.00 uS/cm to 81.90 uS/cm (26.55 percentage) in Tegallalang village, but it increased from 95.00 uS/cm to 154.00 uS/cm (62.21 percentage) in Plaga village, although it still meets to the groundwater quality standard. The increasing of TDS might be cause by gravels or palm tree fibres that not thoroughly cleaned and still contained TDS.