Greenwall filtration system forlakewater treatment: A case study on cocopeat/perlite filter media

Anthropogenic activities often result in varying degrees of lakewater contamination. Conventional lakewater treatment processes require expansive space allocation which could be challenging under certain topographical situations. A greenwall filtration system is a vertical wall that consists of plants or greenery. In this system, greenery is planted in a growing medium made up of a combination of soil, stone, or water. A robust greenwall filtration system could serve as a potential solution for lakewater treatment. However, the efficacy of various filtering media in eliminating contaminants and various water quality indicators such as Chemical Oxygen Demand (COD) from lakewater remains unknown. Previous research has demonstrated that coir and perlite are suitable filter media for a greenwall system. In this study, the effects of various height ratios of the filter media and different lakewater flowrates were investigated. The treatment performance was assessed using various lakewater flowrates: low flowrate (13.10 L/h), medium flowrate (26.57 L/h) and high flowrate (45.18 L/h). The mixed media ratio of 3:1 cocopeat-to-perlite during low flowrate (13.10 L/h) attained the highest removal of COD with an overall removal of 71.00%. It was further discovered that the Langmuir isotherm model could better explain the adsorption process than the Freundlich isotherm model as it possesses an overall high coefficient of determination, R2 where the value of R2 for cocopeat to perlite ratio at 1:1, 1:3, and 3:1; are 0.9397, 0.9823, and 0.5348, respectively.