A thesis submitted in partial fulfillment of requirements for the degree of Master of Engineering, School of Environment, Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 1985

This work was undertaken to study various aspects of water quality, such as existing river water guilty, existing sewerage system , water quality parameters, pollution condition, corrosivity, assimilative capacity and maximum allowable BOD load of Saigon River along 65 km stretch of Ho Chi Minh City Vietnam. From this study it can be said that the existing river water quality of Saigon River is good at the upstream (distance from estuary 40 km) and slightly polluted at downstream. The degree of pollution is shown by the river pollution index of 119.4 - 153.7. The existing BOD load of the river is below the assimilative capacity of the river. However, from the point of view of water uses, the quality of Saigon River water does not meet the requirements for industrial water use and navigation because of high corrosivity. Also, river water is unsuitable for domestic uses because of high contamination with coliform bacteria (MPN: 28010/100 ml). The latter is due to an insufficient sewerage system in Ho Chi Minh City, which is also not properly separated from the water supply system. As only 70% of the population have access to piped water supply, the unhygienically conditions are considered of high importance. Some ameliorative measures are recommended. Investigation of Canals, joining the Saigon River, showed that canal water quality is worse than river water quality with regard to practically all parameters. River water quality parameters are as follows: average K1 and K2 values of 0.09 day and o .13 day-1(30 ° C) respectively, dispersion coefficient of 7.76 - 12.96 m2/s, photosynthetic oxygen production coefficient of 0.39 - 0.75 mg/1-day and oxygen absorption of 4.3 - 5.97 mg/l (29 ° c, 4 hours} . The BOD5/BODu ratio is o.53 and. corrosivity is 11.72 and - 2.84 on Ryznar .Stability lndex (RSI) and Langelier Saturation Index (LSl) respectively.