Effects of irrigation with treated municipal wastewater on soil properties in arid and semi‐arid regions
The use of municipal wastewater for irrigation needs special management. This is due to the environmental and health hazards. In this study, secondary treated municipal wastewater was used in five irrigation treatments. These treatments were as follows: furrow irrigation with normal water (FN), drip irrigation with wastewater (DI), subsurface drip irrigation in 15 cm depth with wastewater (SDI15), subsurface drip irrigation in 30 cm depth with wastewater (SDI30), and furrow irrigation with wastewater (FW). The results showed that the application of DI and SDI sand filters causes a decrease in wastewater index pollution, including 50.1% BOD5, 98.9% total count, 97.6% total coliform, 93.2% faecal coliform, 57.1% nematode, 81% total nitrogen, 52% N-NO3, 84% N-NH4 and 44% total suspended solids. In addition, the application of the SDI system causes a decrease in the moisture content of the soil surface, which decreases total coliform and faecal coliform on the soil surface. The average values for these parameters show no significant difference (5% level) between SDI treatments and FN. The results of this research also show that in the case of SDI with its minimal leaching, prevalence contamination (such as N-NO3) was minimized as a result of the usage of wastewater at depth and in groundwater. Moreover, in SDI treatments, the maximum EC and SAR leaching are observed at 60 cm depth, whereas in the FW this leaching is observed deeper than 90 cm. Copyright # 2008 John Wiley & Sons, Ltd.
keywords: wastewater; irrigation system method; solute transport, arid and semi-arid zone