Assessment of Filtration System Efficiency of Artificial Groundwater Recharge Wells in Lahore

Groundwater recharge is an important process that naturally maintains both water quantity and quality in a given aquifer. However, aquifers of mega cities are shrinking owing to poor urban-water planning and management especially due to lack of surface rainwater recharge systems. Therefore, this study was designed to evaluate the efficiency of filtration system of artificial groundwater recharge wells which is the most viable surface rainwater harvesting (RWH) techniques in urban areas. Henceforth, a total of two artificial surface recharge wells were selected for water sampling from five different points namely rain-gauge, runoff, silt trapper, roughing block and invert well during Monsoon Season in Lahore and characterized in terms of Physico-chemical and microbial parameters. These recharge wells were monitored to evaluate real-time pollutants filtration potential of storm water after every episode of rain. The results revealed that, overall recharged water quality after filtration was quite satisfactory because filtrate media drastically reduced the turbidity level in all examined samples. Other parameters were also within permissible limits according to drinking water quality standards. Overall, 92.5%, 62.7%, 50.06%, 21.42%, 50%, 16.6%, 90% and 99% reduction in turbidity, conductivity, TDS, Na, K, Ca, NO3 and coliform respectively was achieved using installed filter media which was significant statistically (p<0.05). Henceforth, artificial groundwater recharge well is a sustainable, cost-effective tool that reduces burden on urban aquifer, alleviate energy consumption and manage urban rainwater runoff quality without polluting the aquifer.