Soil Aquifer Treatment of Sewage

Intensive agricultural development in the country is posing constraint on the availability of water for crop production. Efforts are being made to make use of marginal quality water for irrigation. Treatment of sewage is necessary before using it for agricultural purpose owing to its toxicity and pathogenic contamination. Sewage from municipal waste was found to be high in BOD, COD, Nitrogen and Coliform with high temporal variability. Soil Aquifer Treatment (SAT) of sewage removed almost all harmful elements in sewage and the renovated water obtained through it was found to be suitable for irrigation. However, with duration of sewage application, the filtrates obtained through SAT showed an increasing value for parameters like pH, Nitogen, Calcium, Magnesium and Sodium while parameters like BOD, Coliform count showed decreasing value. The effect of long term sewage application on soil was cumulative increase in various parameters of soil like electrical conductivity, Nitrogen, Phosphorous, Organic Carbon, Micro nutrients and Heavy metals. The deposition was more in the top 0-40 cm of soil for most parameter, especially micro-nutrients and heavy metals.