عنوان مقاله [English]
Water crisis due to high demand of water in agricultural sector is becoming more evident on day by day basis, hence the use of unconventional water resources, especially drained agricultural water is gaining importance. In this investigation the efficacy of four types of biological filters namely: wheat straw, rice husk, cotton stalk and wood sawdust for improving the quality of agricultural drainage water with respect to factors like, salinity, acidity, nitrate, calcium, magnesium, sodium, phosphate, sulphate, pH, TDS and TSS was investigated under a pilot scale study. Analysis of variance showed that no statistically significant difference between different treatments in terms of the impact on the parameters studied, except for nitrates. Based on the results of this study, all the drainage water filters were effective in improving the quality of wastewater for agriculture, so any of them can be used to this end, since these types of filters are available in all region of the country. The results showed that in terms of eutrophication of water resources, when wastewater discharged to surface water resources, the sawdust and cotton stalk filters, the removed nitrate,was 63.23 and 60.12 percent and the removed phosphate was 20 and 20.7 percent respectively and were superior to other filters. Based on the qualitative analysis of wastewater output of the studied biofilters, and comparing it with standards pertaining to maximum allowable limit for application in agricultural fields, it can be concluded that about 260 million Square meters of drainage water available from irrigation network in Moghan.irrigation network is suitable for production of wheat, barley and cotton under different planting patterns in the region.