Polyaluminium Chloride (PAC) for removing colour, COD and ammonia from semi-aerobic. The removals of colour, COD and ammonia were up to 93%, 56% and 32%, respectively, at an optimum dosage of 2000 mg/L PAC. Rapid and slow mixing speed played only a minor role in the removal efficiencies for colour, COD and ammonia. The flocs size distribution for PAC coagulant shows an increase in floc size with increasing coagulant dosages. PAC also exhibited excellent settling characteristics, with majority of the flocs settled out in the initial 5 min of settling.

Polyaluminium Chloride (PAC) for removing colour, COD and ammonia from semi-aerobic. The removals of colour, COD and ammonia were up to 93%, 56% and 32%, respectively, at an optimum dosage of 2000 mg/L PAC. Rapid and slow mixing speed played only a minor role in the removal efficiencies for colour, COD and ammonia. The flocs size distribution for PAC coagulant shows an increase in floc size with increasing coagulant dosages. PAC also exhibited excellent settling characteristics, with majority of the flocs settled out in the initial 5 min of settling.