Performance of filter media for improving the irrigation water quality of village pond

Abstract

With the increased addition of household wastewater in the village pond, the water quality of the pond was deteriorating rendering it unsuitable for irrigation. Therefore, a study was conducted to treat the pond water for making it suitable for irrigation using different types of filter media. The five types of filter media viz., biochar, activated charcoal, zeolite, fine sand and coarse sand were individually tested for the quality improvement of the pond water for irrigation. The water quality parameters, such as BOD, COD, TDS, TSS, TS, pH, and EC were analysed before and after passing through the filter media. The discharge of treated water for media thickness of 30 and 40 cm and water head of 10, 20 and 30 cm was passed through each filter media and discharge was collected for the water quality analysis. The BOD, COD, and TSS decreased by 12, 9.7 and 28%, respectively due to the combined effect of activated charcoal, zeolite and fine sand, respectively. To further enhance the performance of the filter materials, the study was conducted with the controlled discharge of 5 and 8 l h-1 through the same thickness of filter media. The discharge rate of 5 l h-1, materials depth of 40 cm and water head of 10 cm decreased the values of BOD, COD, TSS and TDS more efficiently than the uncontrolled flow of water and discharge rate 8 l h-1. The 40 cm depth of material was found more efficient than the 30 cm depth of material whereas there was an insignificant difference in the efficiency at 10, 20 and 30 cm heads therefore, the 10 cm head along with the 40 cm material depth was selected. Efficient materials based on the removal efficiency were selected (zeolite, activated charcoal, biochar and fine sand) and each selected material having a depth of 40 cm were put in the column one over the other by keeping course material at the bottom and finer at the top and water head 10 cm (Biochar, activated charcoal, zeolite and fine sand at top). Two cycles of 24, 48, 96 and 168 hrs duration were performed and treated water was collected at the outlet of the filter media for determination of quality parameters. For a combination of materials keeping the thickness of each material as 40 cm, the efficiency of 49, 57, 75, and 10% was achieved in terms of BOD, COD, TSS, and TDS.