SDAO工艺污水厂提标改造为A^2O和MUCT工艺的对比试验

Comparative Experimental Study on A^2O and MUCT Processes for the Improvement of Discharge Standards and Reconstruction of Wastewater Treatment Plant with SDAO Process

基于生物脱氮除磷的机理,在不增加新构筑物和不进行较大结构改造的前提下,研究将污水处理厂SDAO工艺提标改造为A2O和MUCT工艺的处理效果与差异。结果表明,驯化前期进水C/N为3.25,A2O和MUCT工艺的CODCr和NH4+-N去除率可达90.0%以上,但TN和TP去除率较低;后期补充一定量的碳源可明显提高同步脱氮除磷效果。反应器稳定运行后维持进水C/N为6.75时,A2O工艺在稳定运行条件下,TN去除率可达75.6%,出水TN平均浓度为15.6mg/L;TP去除率可达78.8%,出水TP平均浓度为1.4mg/L。MUCT工艺脱氮除磷效果相对较差,稳定运行条件下TN和TP去除率仅达62.8%和37.3%,出水TN和TP平均浓度分别为25.3和2.8mg/L。分段进水可改善MUCT工艺的处理效果,稳定运行条件下,出水TN和TP的浓度分别为20.3和0.9mg/L,去除率分别为72.8%和86.8%。研究认为,在SDAO工艺的提标改造过程中,A2O工艺相对MUCT工艺具有明显优势,出水CODCr、NH4+-N及TN接近GB18918—2002《城镇污水处理厂污染物排放标准》中一级A标准,出水TP可达一级B标准,需辅以化学除磷手段达到一级A标准。

Based on the biological nitrogen and phosphorous removal mechanisms, the treatment effects and differences of transforming SDAO process into A20 process and MUCT process without additional building and apparent structural modification were studied. The results showed that the removal efficiency of CODcr and NH4＋ -N in both processes could reach above 90.0% , but with the relatively low TN and TP removal efficiencies under the condition of influent C/N = 3. 25 during the early domestication period. Nitrogen and phosphorous removal efficiency could be considerably improved by supplementing additional carbon source. After improving the C/N to 6.75 and keeping the A2O process at stable operation, the TN and TP removal efficiencies of 75.6% and 78.8% could be reached with effluent TN of 15.6 mg/L and TP of 1.4 mg/L, respectively. The removal efficiency of MUCT process was not as good as A2O： the removal efficiencies of TN and TP were 62.8% and 37.3%, and the average effluent TN and TP were 25.3 mg/L and 2.8 mg/L, respectively. Step-feed could improve the removal efficiencies of MUCT： under stable operations, the TN and TP removal efficiencies could be improved to 72.8% and 86.8%, with effluent TN of 20.3 mg/L and TP of 0.9 mg/L, respectively. In conclusion, the A20 process had more obvious advantages than the MUCT process when used for the improvement of discharge standards and for the reconstruction of SDAO process. The effluent CODcr, NH4＋-N and TN of A20 process met the requirements of Class 1 A discharge standards of the National Standard （GB 18918-2002）; while the effluent TP could meet the Class 1B standard, and additional chemical phosphorus removal was thus required to meet the Class 1A discharge standard.