Performance evaluation of two filter materials in intermittent sand filtration system

Abstract

The environment is a treasure that needs to be protected from point and diffuse sources of pollution. Mostwastewater treatment plants cannot attain 100% efficiencies and this call for tertiary treatment process beforedischarging final treated wastewater into the environment. The study focused on harnessing the locally availablematerials, sand and granulated Palm Kernel Shell (gPKS) as filters for treatment of wastewater from constructedwetland using intermittent filtration system in the laboratory. The filter depth and hydraulic loading rate was 650 mmand 0.135 L $min^{-1}$, respectively. Applied wastewater was effluent from the Constructed Wetland (CW) of wastewatertreatment plant University of Lagos. The filtration system was dosed intermittently 6 hourly for 12 weeks.Experimental results showed that pH of the effluent from gPKS filter medium was slightly reduced to the influent dueto acidic nature of the gPKS while effluent from sand filter slightly increased. The five day biochemical oxygen demand(BOD5) removal efficiency for the gPKS and sand filters were 59.2 and 69.08% respectively, while the correspondingaverage Dissolve Oxygen (DO) were 2.9 ± 0.6 mg $L^{-1}$ and 3.4 ± 0.345. The percentage removal of E. coli in sand andgPKS filters are 69.34% and 87.49% respectively.