TR(BR)-141 : Impact of sewage waste disposal on soil strata and ground water quality

Abstract

Land application of sewage waste raises many environmental issues both as potential resource for fertilizers and a source of pollution. Their contents of trace elements and pathogens represent potential risk for human health. Because of their accumulation in the soil surface, trace elements may induce metabolism problems in plants and animals and consequently contaminate the food chains. The contaminant migration in the soil, although limited, may lead to ground water pollution. The objective of this study is to provide information on utilization of sewage waste for irrigation purposes and their impact on the soil strata and ground water quality.

The characterization of sewage waste indicated that the waste can be used for irrigation purposes. The concentration of various constituents monitored are within normal range and do not constitute a limiting factor for irrigation use. As• per the U.S. Salinity Laboratory Classification, the waste water of the BHEL complex falls under the category of medium salinity and low SAR (C2-S1) which is suitable for irrigation purposes. The sewage waste characteristics studied in this report can be considered to have low contaminant levels and can be used for irrigation purposes.

The spatial distribution of total concentration of various constituents in the soil profile showed that most of the constituents are retained within the top 60-75 cm and no substantial migration took place in the soil strata. The quality of ground water in the nearby area is quite normal and does not indicate any appreciable sign of contamination due to land application of sewage waste. However, a management strategy for proper land application of sewage waste should be set up to maintain the sustainability of soils to assimilate pollutants and prevent food chain transfer of hazardous elements.