Denitrification of Nitrate-Contaminated Water Using Poly (3-Hydroxybutyrate-co-3-Hydroxyvalerate) as Carbon Source

Nitrate removal from the synthetic water medium was investigated using Poly (3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PHBV) as solid carbon source and the supporter for microorganisms. The experiments were carried out by batch and continuous modes, respectively. The batch experiment results indicated that a stable denitrification rate (1.22 mg NO₃-N/(m²·h)) was achieved after 20-day acclimation. The colonization of substrate by bacteria was the rate limiting factor for nitrate removal. The continuous flow reactor packed with PHBV as carbon source started up easily, and denitrification rate increased gradually with running time. After 2-week running, a stable denitrification rate was reached, and 90% nitrate was removal from the influent containing 30mg/L NO₃-N with 3 h hydraulic retention time (HRT). HRT is a crucial factor for the denitrification reactor. Removal efficiency of nitrate decreased to 70%with 2h HRT.