Lake Water Treatment Using Green Wall System: Effects of Filter Media Ratio and Lake Water Flow Rate on Treatment Performance

Lake water pollution has become a growing concern over the years. Therefore, alternative water treatment solutions are needed to address this issue. Green wall is considered as a potential alternative to treat lake water. However, the treatment performance of filtering media in removing lake water pollutants is unknown. Previous studies suggested that coir and perlite could be the potential filter media for the green wall system. Hence, this research studied the pollutant removal efficiency of various ratios of combined media. Thereafter, the treatment performance was evaluated with different lake water flow rate. The result showed that the 3:1 coir-to-perlite combined media ratio achieved the highest chemical oxygen demand (COD), total suspended solid (TSS) and turbidity removal with constant hydraulic load. This suggested that coir played an important role in governing both physico-chemical and biological processes due to the impact of retention time on the removal. It was found that the removal of pollutants was insignificant when the lake water flow rate is higher and lower than 28 L/h. This study also indicated that the lake water flowrate of 28 L/h managed to achieve consistent removal in COD, turbidity, TSS and TN with 53%, 54%, 41% and 52% removal, respectively.