Wastewater with Low C/N Ratio Treated by Partial Nitrification/Anammox Process

Using synthetic wastewater and sludge dewatering effluent as influent, respectively, wastewater with low C/N ratio treated by partial nitrification/anammox process was investigated. The results showed that half partial nitrification can be accomplished in CSTR at DO of 0.5-1.0 mg/L and HRT of 24 h, the average effluent ratio of NO₂ ^--N/NH₄ ⁺-N maintained at about 1.25 and the average effluent ratio of [NO₂ ^--N]/[NO_x ^--N] kept above 97.52%. The partial nitrification/anammox process was suitable to treat wastewater with low C/N ratio. When synthetic wastewater was treated, TN removal percent of 87.53% was obtained. When sludge dewatering effluent was treated, the total nitrogen removal loading rate was up to 0.143 kg/m³ldrd with TN removal percent of 86.82% and COD removal percent of 84.88% after 29 d operation. When wastewater with low C/N ratio was treated by partial nitrification/anammox process, nitrogen was mostly removed through anammox reactor while organic matter was mostly removed through partial nitrification reactor.