用于城市污水脱氮的新型生态陶粒混凝土挂膜特征

Characteristics of Biofilm Colonization in New Ecological Ceramsite Concrete Used in Nitrogen Removal from Municipal Wastewater

以粉煤灰陶粒为粗骨料，辅以水泥、高效减水剂等制成新型生态陶粒混凝土，作为自行构建的交替好氧缺氧生物膜反应器（简称ECCBR）的载体，用于城市污水脱氮。采用间歇运行和间歇曝气方式，在不同DO、C／N值等条件下进行挂膜试验，结果显示，挂膜周期主要受水温影响，25-31℃时为8-10d，15-17℃时为13～15d；DO对去除污染物的影响较其他因素明显，浓度宜控制为1．5mg／L；生物膜成熟时，对COD、氨氮和总氮的最高去除率分别为96．4％、94．0％和81．4％，出水浓度均在《城镇污水处理厂污染物排放标准》（GB18918_2002）的一级A标准以内，此时进水COD、氨氮和总氮浓度分别为200、18．1和19．9mg／L，循环水流量为667L／h；SOUR沿程变化甚微，反应器末端依然可以维持较高的微生物活性。新型生态陶粒混凝土投资低、挂膜周期短、脱氮率较高、抗冲击负荷，通过进一步开发可作为城市污水高效低耗脱氮的又一生物膜载体。

A new kind of ecological ceramsite concrete was developed using lytag as coarse aggre- gate and supplementing cement and high-efficiency water reducing agent. It was used as carrier in a self- built ecological eeramsite concrete biofilm reactor （ECCBR） to remove nitrogen from municipal wastewater. A test was performed for biofilm colonization in ECCBR operated in intermittent operation and intermittent aeration modes under different DO and C/N ratio conditions. The results showed that the pe- riod of biofilm colonization was mainly affected by wastewater temperature which meant 25 to 31 ℃ for 8 to 10 d and 15 to 17 ℃ for 13 to 15 d. DO had more pronounced effect on pollutants removal than other parameters. DO concentration should be controlled at 1.5 mg/L. When biofilm was matured, the highest removal rates of COD, ammonia nitrogen and total nitrogen were 96.4% , 94.0% and 81.4% , respec- tively. The effluent concentrations of the pollutants met the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （ GB 18918 - 2002）. The influent con-centrations of COD, ammonia nitrogen and total nitrogen were 200 rag/L, 18.1 mg/L and 19.9 rag/L, respectively, and the circulating water flow was 667 L/h. SOUR changed little along its path, and high microbial activity could still be maintained at the end of the reactor. The new ecological ceramsite con- crete has advantages of low investment, short cycle of biofilm colonization, high nitrogen removal rate and strong resistance to impact load. Through further development, it can become a biofilm carrier used for high-efficiency and low-consumption nitrogen removal in municipal wastewater treatment.