Effects of Nitrate Concentration on Heterotrophic Denitrification in Wastewater Using Poly (Butylene Succinate) as a Carbon Source and Carrier

Abstract

Biodegradable polymer pellets (BDPs) can act as biofilm carrier and as water insoluble carbon source for denitrification simultaneously, which is accessible only by enzymatic attack. It is expected that organic carbon source for heterotrophic denitrification by using BDPs will not be overdose or shortage. The current batch experiment was conducted to examine if the PBS would supply enough carbon source to the denitrification with high concentration nitrate. The initial nitrate nitrogen (NO3--N) concentrations were 100 mg NO3-N/l (T1), 300 mg NO3-N/l (T2) and 500 mg NO3-N/l (T3) respectively. The results showed that the initial nitrate concentrations have significant effects on the removal of nitrate nitrogen and total nitrogen (TN) using PBS as carbon source. The efficiencies of removal of nitrate and TN in T1 were almost 100%. The amounts of NO3--N and TN that were removed in T2 were 286.60±6.66 mg NO3-N/g PBS (in dry wt), which was significantly higher than that of T1 and T3. Accumulation of ammonium and nitrite were observed in T2 and T3. The morphological changes and the weight losses observed for PBS granules indicated that good degradation occurred in static denitrification environments. But the insufficient of carbon sources for denitrification in T2 and T3 was observed.