Performance Evaluation of Clay-Sawdust Composite Filter for Point of Use Water Treatment

Abstract

Water borne diseases have remained a major challenge in most developing countries. This is usually as a result of lack of access to clean water and contamination associated with water fetching and conveyance. This work explores the possibility of improving water quality and eliminating the possibility of recontamination by the use of point of use (POU) water filters made from cheap locally available materials. The performance of POU water filters for the purification of water obtained from various sources was investigated. Sawdust was used as a burnout material in order to enhance the rate of filtration. The clay was first characterized and then various proportions (5%, 10%, 20%, 30% and 50% by weight) of sawdust were mixed with the clay for filter production. The clay was found to have a specific gravity of 2.4, a high liquid limit of 81.6% and a medium plastic limit of 48.54%. The flow rates of the filters ranged between 0.0005litres/hr for the filter with 5% sawdust and 0.8litres/hr for the filter with 50% sawdust. The average removal of suspended solids (SS) and biochemical oxygen demand (BOD) was 98.6% and 33% respectively while the mean Log10 reduction in total count (TC) was 93.1%. Result of analysis of variance showed that there was no significant difference between the performances of the filters. However, there was a significant difference between the flow rates with F(18.71) > F critical (5.14). This implies that while burnout materials improve water quality, increasing burnout materials in clay filters beyond 50% does not significantly affect the performance for the filter with respect to the quality of effluent but with respect to flow rate.

Application of activated carbon impregnated composite ceramic filters in cassava mill effluent treatment: prospects and limitations

“…Therefore, the rate of water discharged increases with filter porosity. This compares well with similar studies by Lantagne (2001), Nnaji et al (2016), and Zereffa and Bekalo (2017). In this study, the flow rate dropped significantly with time.…”

“…The pore size and pore size distribution, hydraulic head above the filter and the suspended solids (SS) of the source water determine the filters' performance and pollutants removal efficiency. The scrubbing frequency is also a function of the suspended solids load in the source water (Nnaji et al, 2016). The filter flow rate was observed to increase with the increase in the proportion of sawdust and activated carbon as shown in Table 3.…”

“…This is equivalent to particles of diameter less than or equal to 119 μm ( Figure 1). The clay was prepared as described by Nnaji et al (2016). All the parameters are in mg/l except Electrical conductivity (µS/cm) and Turbidity (NTU).…”

“…The filters were later sintered at 850°C in an industrial kiln for 72 hours and allowed to cool gradually in the kiln. This is to further reduce the porosity and increase the filter density and strength (Nnaji et al, 2016). The filters were prepared for filtration as described by Nnaji et al (2016) and tested by measuring the amount of filtrate that percolated through the filter after 1 hour as reported by Soppe et al (2015).…”

“…This is to further reduce the porosity and increase the filter density and strength (Nnaji et al, 2016). The filters were prepared for filtration as described by Nnaji et al (2016) and tested by measuring the amount of filtrate that percolated through the filter after 1 hour as reported by Soppe et al (2015). Filtrate samples were collected in plastic containers and taken to the laboratory for analysis.…”