Analysis of water quality in Saigon River water and its treatment by traditional coagulation – flocculation

Abstract

In natural water, colloidal particles play an important role in the transport of organic compounds, including pollutants. The analysis of colloidal particles creates more bases for the selection of river water treatment technology, making the treatment more efficient. In this study, the size and zeta potential of colloidal particles in Saigon river water were determined. Seven sampling sites were randomly selected along the river length in Ho Chi Minh City. One of the locations was selected to investigate colloidal properties at different times (i.e. 10 samples). The results showed that the colloidal particles have poor stability with Zeta potentials in the range from -19 mV to -12 mV. Besides, statistical analysis showed that the zeta potential had an inverse correlation with the pH value and the permanganate index with the significant coefficients of -0.67 and -0.73, respectively. The size of colloidal particles in water is not uniform; however, due to poor stability, part of the particles join together and settle down. Coagulation-flocculation-sedimentation-rapid sand filtration experiments were also performed to remove colloidal particles from the water. The treated water has low turbidity with a removal efficiency of 97%. This shows that the colloidal particles presented in the Saigon River water could be easily removed by the traditional physicochemical method. However, the parameters of the permanganate index and Coliforms did not meet the standard of QCVN 01-1/2018/BYT for drinking purposes, which still require further treatment.