三段式硝化型生物接触氧化反应器的启动及特性

The start-up and characterization of a three-stage nitrification biological contact oxidation reactor

采用实际生活污水,研究了三段式串联的硝化型生物接触氧化反应器的挂膜启动及各段的硝化特性.试验结果表明:利用中间沉淀池出水作为生物接触氧化反应器的进水进行自然挂膜,在无需投加接种污泥的情况下,20d挂膜成熟,NH4+-N的去除率达到98%以上.反应器中随着沿程推流,三段的生物量和生物膜厚度逐渐降低,最大的生物量和生物膜厚度分别为1271.25mg/L和119.45μm.分析各段的硝化特性,发现三段在低温15℃条件下仍具有较高的比硝化速率,并且在同一温度下(15,23,32℃),第2、3段的比硝化速率均大于第1段.针对上述现象,根据比耗氧速率SOUR粗略估计了AOB和NOB在各段中的相对比例.3段AOB的百分比分别为(25.64+4.89)%,(34.59+5.02)%,(42.50+1.57)%,而NOB的百分比为(23.52+3.35)%,(39.65+4.26)%,(40.69+2.19)%.此外,系统运行125d的FISH结果表明,3段的微生物菌群分布确实存在差异.与第1段相比,后2段的AOB和NOB更容易成为优势菌.

The start-up and characterization of a three-stage nitrification biological contact oxidation reactor were studied using actual sewage. The experimental results showed that by using the intermediate sedimentation tank effluent as influent for the biofilm incubation in biological contact oxidation reactor, the biofilm matured within 20 day without additional inoculation sludge, and the NH4±-N removal efficiency reached above 98%. The biomass and biofilm thickness of three stages gradually decreased in the flow direction, and the highest biomass and biofilm thickness were 1271.25mg/L and 119.45 μm respectively. By analyzing the nitrifying characteristics, the results revealed that the three stages had higher specific nitrification uptake rate （SNUR） even at low temperature of 15℃, and the second and third stages were both higher than the first stage at the same temperature （15, 23, 32℃）. In view of the above phenomenon, the ammonia oxidizing bacteria （AOB） and nitrite oxidizing bacteria （NOB） ratio in each stage were roughly estimated according to the specific oxygen uptake rate （SOUR）. The AOB of three stages were （25.64±4.89）%, （34.59±5.02）% and （42.50±1.57）% while the NOB were （23.52±3.35）%, （39.65±4.26）%, （40.69±2.19）% respectively. In addition, the fluorescence in situ hybridization （FISH） results derived on day 125after initial operation showed that the bacterial distribution of three stages do exist differences.The AOB and NOB were more dominant in the second and third stages, compared to the first stage.