Applicability of industrial wastewater as carbon source for denitrification of a sludge dewatering liquor

The applicability of four industrial waste streams from potato processing, canola processing and oil refining, biodiesel production (glycerol), and glycol as substitutes to methanol and ethanol in denitrification of anaerobically digested sludge dewatering liquor (centrate) was evaluated in bench-scale sequencing batch reactors. It was found that glycerol was the best substitute with the specific denitrification rate (SDNR) of 13mgNO (3)-N/(gVSS center dot h) followed by potato processing wastewater at 12mg NO (3)-N/(gVSS center dot h ). Both substrates produced faster SDNR than methanol's 10mg NO (3)-N/(gVSS center dot h ); however, they were inferior to ethanol's 17mg NO (3)-N/(gVSS center dot h ). Glycol had SDNR of 8mg NO (3)-N/(gVSS center dot h ) and demonstrated a very fast acclimation rate, i.e. the response in increased denitrification rate was visible in three days following glycol addition. Canola processing and oil refining wastewater was considered an inappropriate carbon source due to a low SDNR of 5mg NO (3)-N/(gVSS center dot h ) and apparent inhibitory effect on nitrification.