Assessing changes in surface water quality and pollutant load in Dong Nai province

Abstract

This study aims at assessing changes in the surface water quality in Dong Nai province (2010- 2014). In addtion, the pollutant loads of wastewater sources were calculated till 2020–2030 with 03 wastewater treatment scenarios serving for the local environmental management. The water quality index (WQI) showed the surface water quality of Dong Nai Province to be gradually improved during the dry season but significantly declined in the rainy season in the last 5 years due to high concentrations of suspended solids (SS), Fe and microorganism - especially in the 3rd segment of Dong Nai river through Bien Hoa City. This current status certainly relates to pollutant loads from waste water sources in the province. Pollutant loads of domestic and industrial wastewater in Bien Hoa city are the highest (40 % per source), livestock activities in Xuan Loc district account for 20 %; aquaculture activities in Nhon Trach district contribute more than 75 % of the corresponding total loads, etc. in which loads of BOD5, COD and SS are significant, about 581,570 tons, 1,035,403 tons and 639,153 tons per year, respectively, and tend to increase in the future, requiring appropriate solutions.