This study was conducted to investigate the\ncharacteristics of inflow and outflow wastewater of the\nBandargaz wastewater treatment plant on the basis of the\ndata collection of operation period and the samples taken\nduring the study. Also the effects of mid-term use of the\nwastewater for irrigation (from 2005 to 2013) on soil\nphysical and chemical characteristics were studied. For\nthis purpose, 4 samples were taken from the inflow and\noutflow wastewater and 25 quality parameters were measured.\nAlso, the four soil samples from a depth of 0ââ?¬â??30 cm\nof two rice field irrigated with wastewater in the beginning\nand middle of the planting season and two samples from\none adjacent rice field irrigated with fresh water were\ncollected and their chemical and physical characteristics\nwere determined. Average of electrical conductivity, total\ndissolved solids, sodium adsorption ratio, chemical oxygen\ndemand and 5 days biochemical oxygen demand in treated\nwastewater were 1.35 dS/m, 707 ppm, 0.93, 80 ppm and\n40 ppm, respectively. Results showed that although some\nrestrictions exist about chlorine and bicarbonate, the\ntreated wastewater is suitable for irrigation based on\nnational and international standards and criteria. In comparison\nwith fresh water, the mid-term use of wastewater\ncaused a little increase of soil salinity. However, it did not\nlead to increase of soil salinity beyond rice salinity\nthreshold. Also, there were no restrictions on soil in the\naspect of salinity and sodium hazard on the basis of many\nirrigated soil classifications. In comparison with fresh\nwater, the mid-term use of wastewater caused the increase\nof total N, absorbable P and absorbable K in soil due\nto high concentration of those elements in treated\nwastewater.
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