The overall purpose was to assess the feasibilities of recycling filter backwash water (FBWW) and combined filter backwash water (CFBWW) in a drinking water treatment plant in south China. The variations of regular water-quality indexes, metal indexes (Al, Mn and Cd), polyacrylamide and disinfection by-product indexes (trihalomethanes and their formation potentials) along with the treatment and the recycle processes were monitored. Results showed the recycling procedure caused the increases of turbidity, total solids, ammonia nitrogen (NH3-N), permanganate index (CODMn), dissolved organic carbon , Al, Mn and Cd concentrations in mixture of raw water and FBWW or CFBWW compared to those in raw water. However, the recycling procedure had negligible impacts on the qualities of settled water and filtered water because most of the contaminants could be effectively removed by the conventional water treatment process. Although recycling did cause slight increases of NH3-N and CODMn levels in settled water and filtered water, the quality of finished water always conformed to Chinese standards for drinking water quality according to the surveyed index in the present study. Thus, it is appropriate to recycle waste streams in water-stressed areas if the source water is well managed and the water treatment processes are carefully conducted.
- combined filter backwash water (CFBWW)
- filter backwash water (FBWW)
- wastewater recycle
- water quality
- First received 23 December 2015.
- Accepted in revised form 5 September 2016.
- © IWA Publishing 2016