[Denitrification using PBS as carbon source and biofilm supporter: effect of pH]

PBS, a new kind of biodegradable polymers (BDPs), was used as carbon source and biofilm carrier to remove nitrate from drinking water. The effect of pH was investigated in detail and the results show that fine biofilm can form on the surface of PBS granules and protect denitrifiers. PBS denitrification system can endure higher pH shocking than that of traditional carrier. When influent pH was between 5.0 to approximately 9.0, effluent pH tended to be neutral and denitrification rate was 0.60 to approximately 0.63 mg/(g x d) while the maximum value was 0.70 mg/(g x d) (pH 7.5 to approximately 8.0). Effluent nitrite level was unstable when pH of solution was 6 to approximately 8. It was as high as 0.7 mg/L when pH was below 6 and no more than 0.1 mg/L when pH was higher than 8.