剩余污泥碱解液用作低C/N合成氨废水反硝化碳源研究

APPLICATION OF ALKALI-HYDROLYZED RESIDUAL OF ACTIVATED SLUDGE AS A DENITRIFICATION CARBON SOURCE FOR TREATING AMMONIA WASTEWATER WITH A LOW C/N RATIO

针对低C/N合成氨废水反硝化脱氮处理中碳源不足的难题,探究了以剩余污泥碱解液作为补充碳源的可行性。结果显示:与葡萄糖和甲醇相比,碱解液作为碳源时,体系的反硝化速率分别提高了25.3%和23.7%。通过优化实验条件获得最佳反硝化脱氮工艺参数:C/N=5.5,T=35℃,初始pH=8,水力停留时间为5 h。此条件下NO;-N去除率达86%以上,NO;-N无积累。将污泥碱解液用于A/O工艺处理大连化学工业公司低C/N合成氨废水,碱解液以稀释方式加入厌氧段,投加量使原低C/N合成氨氮废水C/N=5.5左右。A/O工艺连续运行结果显示:出水ρ(TN)<15 mg/L,ρ(NH^(+)_(4)-N)<5 mg/L,NO^(+)_(2)-N基本无积累,出水氮素指标均达到GB 18918—2002《城镇污水处理厂污染物排放标准》一级A排放标准。研究证实了污泥碱解液适用于低C/N合成氨废水的处理,为此类废水的处理和剩余污泥的资源化处置提供了有力支撑。

This work investigated the feasibility of using alkali-hydrolyzed residual activated sludge as a denitrification carbon source to treat ammonia wastewater with a low C/N ratio. Batch experimental results showed that, compared to glucose and methanol, the denitrification rate using sludge alkali-hydrolysate was increased by 25.3% and 23.7%, respectively. The optimal parameters for nitrogen removal through denitrification were C/N=5.5, T=35 ℃, initial pH=8, and HRT=5 h. Under this conditions, NO;-N was almost completely removed without NO;-N accumulated. Subsequently, the sludge alkali-hydrolysate was applied to an A/O process to treat actual ammonia wastewater with a low C/N ratio. The A/O process was operated in continuous mode, and the sludge alkali-hydrolysate was supplemented in the anaerobic tank with an influent C/N ratio of 5.5. The effluent monitoring results showed that the ρ(TN)<15 mg/L, ρ(NH^(+)_(4)-N)<5 mg/L with almost no NO^(+)_(2)-N accumulation, which all reached the first-level A emission limiting value in Discharge Standard of Pollutants for Municipal Wastewater treatment Plant. This work revealed that the sludge alkali-hydrolysate could be successfully used to treat actual ammonia wastewater with a low C/N ratio, and provided theoretical and practical support for treatment of nitrogen-containing wastewater and utilization of residual sludge.