Purifications of petroleum products contaminated water using modified rice husk ash filters

Abstract

This study evaluated the effects of different ceramic candle filters made from blends of rice husk ash (RHA), polyethylene glycol (PEG), and clay for effectiveness in purifying petroleum products contaminated water. The filters were characterized for porosity, swellability and water permeability. Performances of the candle filters were evaluated based on the physicochemical analysis of the untreated and purified water samples. The parameters measured include total dissolved solids (TDS), hardness, phosphates, nitrates, and chloride. Results from this investigation indicated that water diffusion in the filters, depends on filter dimensions-as permeability increased with decrease in filter’s surface area. This was also seen in the average flux obtained for the candles. The filter EL4 has a flux of 0.0070 ml/min.cm2, EL3 has 0.0199 ml/min.cm2. Also, the porosity of the filters increased with the amount of porogen used. An improvement in physical appearance of the water samples was seen after purification of the contaminated water. The chloride and TDS content of the untreated water samples were 260.1 ± 7.705 mg/L and 596.7 ± 30.32 mg/L respectively, while the chloride and TDS contents of filtrates obtained from filter made from RHA/Eleme clay and PEG as porogen (EL3) to 246.4 ± 1.915 mg/L and 511.7 ± 13.3 mg/L respectively. All the filters increased the phosphate and nitrate contents of filtrates compared to the untreated water samples. Total polycyclic hydrocarbon was reduced up to 85% by EL4 filter. The values of heavy metals found in the water samples were within the permissible limit for irrigation water. The low preparation cost, ease of preparation and purification results of these candle filters will boost their applications for water remediation in areas with high level of contamination particularly for irrigation and other household purposes but not drinking and cooking.