Chau Pha Lake is one of the large reservoirs providing water for domestic, irrigation and production of people in Phu My town, Ba Ria Vung Tau province. This study was conducted to analyze the parameters of pH, temperature, DO, BOD5, COD, N-NH4+, P-PO43-, TSS, turbidity, total Coliform on 16 samples in 2020 and the water quality index calculation WQI. The analysis results show that the water quality of Chau Pha lake in the rainy season is quite good, all parameters reach the limit value A2 according to QCVN 08:2015/BTNMT; however, in the dry season, the values of parameters DO, BOD5, P-PO43, TSS exceed the limit value A2 but not significantly; WQI values fluctuate at a fairly high level from 71 to 92, which is correlated with turbidity, COD, and BOD5 parameters. Thus, the average WQI of the lake reaches 85.4 points, corresponding to level 2 (green) - water used for domestic water supply purposes but needs appropriate treatment measures.

The wastewater treatment plant is an extremely important infrastructure to ensure the quality of life, water use of human life, and other ways to ensure water quality for the natural environment. In the operation of it, there are always potential hazards affecting the health of the workers working in the factory. The study was performed using the Semi-quantitative risk assessment method to calculate the values of operational risks in the water treatment plant (WWP). The results of the study obtained 18 high potential hazards that may lead to the present in the water treatment process. The hazards were the leakage of deodorizing towers and the generation of toxic emissions of dead microorganisms that have the highest value with a risk scale of 20 points- frequent impacts on employees. The study has also identified the dangers present in WWP and this will be the premise for mitigating solutions for problems occurring at its.

The current status assessment research of water use and quality of supplied domestic water in Thu Dau Mot city, Binh Duong province, as well as the clean water use situation of the local people. Sampling and assessment of the quality of supplied water at Thu Dau Mot Water supply enterprise. The water treatment process here is strictly conducted to ensure stability, constant pressure, inlet and outlet water flow. The analysis results of physical and chemical parameters of water quality at Thu Dau Mot Water supply enterprise show parameters within the allowable limits of water standards for domestic use QCVN 02: 2009/BYT and domestic water QCVN 01: 2009/BYT. However, during the water treatment process in the rainy season, it is time consuming and costly for the use of many chemicals in the treatment process, as high turbidity and high color temperature, low TDS, low pH, low chloride, high SS, Fe and Mn content changes in the wet season higher than in the dry season. After sampling for analysis and treatment, the output water meets the clean water standard to meet the needs of the people in Thu Dau Mot City and surrounding areas. Keywords: water quality, physical and chemical parameters, water standards, clean water.

Bien Hoa City is an urban area of Dong Nai province located in the Southern key economic region. Currently, Bien Hoa City has 6 industrial parks in operation with large daily wastewater flow, causing environmental risks, especially from organic pollutants. The study applied the Nemerow risk index and the geographic information systems (GIS). The results showed that the industrial parks were mainly organic pollution levels including N-total, P-total, and Ammonium. The level of environmental risk from organic pollution was recorded in range of medium to very high levels, the ranked in descending order: Agtex Long Binh Industrial Park (P = 24)> Amata Industrial Park (P = 16)> Bien Hoa 2 Industrial Park ( P = 10),> Tam Phuoc Industrial Park (P = 5)> Loteco Industrial Park (P = 3). The results of the study provided good information for the management and improvement of wastewater quality in the industrial wastewater treatment plants of the industrial parks in Bien Hoa City.