Assessment of irrigation water reuses potentiality of Dhaka Export Processing Zone (DEPZ) wastewater and its impact on soil toxicity

The suitability of wastewater (WW) irrigation collected from Dhaka Export Processing Zone (DEPZ) was assessed against standard for irrigation water in Bangladesh. The WW was unsuitable for reuse in terms of physicochemical properties and medium SAR hazard. To observe the impact of soil nutrient in top soil, subsoil and bottom soil layers, two experimental plots were prepared. Control plot was irrigated by freshwater while the other plot was irrigated by WW collected from DEPZ in the ratio of 15% freshwater to 85% WW In both plots one month old BR-29 rice seedlings were transplanted. After 105 days, the soil layers were examined against the background soil data which indicated arise of slight soil salinity problem (percentile change was 68.51%) in comparison to the control plot. Metal Enrichment factor was also calculated for Cu, Fe, Mn and Zn which was below 1, indicating no pollution.