This study was conducted to assess the quality of domestic, aquaculture, industrial and traditional village wastewater effluents in Dong Thap province. Monitoring data was collected in March (dry season) and September (rainy season) from the Department of Natural Resources and Environment of Dong Thap province in 2019. The domestic wastewater samples were collected at five locations (denoted from S1-S5), industrial and traditional village wastewater were collected at the locations from S6 to S10. The parameters of pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), ammonium (NH₄⁺-N), nitrate (NO₃^--N), total nitrogen (TN), orthophosphate (PO₄^3--P), total phosphorus (TP), sulfide (S₂^-), oil and greases, mineral oil and grease and coliforms were used to evaluate wastewater quality. The quality of domestic wastewater is compared with national technical regulation on domestic wastewater QCVN 14: 2008/BTNMT (column A) while industrial and traditional village wastewater effluent are compared with national technical regulation of QCVN 40:2011/BTNMT (column A). The results showed that domestic wastewater effluent contained high organic matters (BOD, TSS), nutrients (NH₄⁺-N, PO₄^3--P) and microorganism (coliform). The values ​​of BOD, NH₄⁺-N, PO₄^3--P and coliform in the dry season exceeded the permissible limits of QCVN 14:2008/BTNMT, and higher than those in the rainy season. Quality of wastewater effluents in traditional villages and industrial zones have a lower concentration of pollutants than those in domestic wastewater, but BOD, COD, TSS, TN, NH₄⁺-N, TP and coliform were still higher than those regulated in QCVN 40:2011/BTNMT. The study found that the effluents of the wastewaters have a high concentration of pollutants, which limits the ability to use water for domestic water supply purposes and negatively impacts the aquatic ecosystem. Therefore, it is necessary to have appropriate collection and treatment measures to ensure the quality of the receiving water.

Keywords: Organic matter, domestic wastewater, industrial and traditional village wastewater, microorganism, Dong Thap.