低温高铁锰氨氮地下水两级生物净化工艺

Two-stage bio-purification technology of low temperature groundwater containing high concentration of iron, manganese and ammonia nitrogen

摘要:

针对“一级曝气+一级过滤”生物净化工艺处理低温(5~7.8 ℃)、高氨氮(ρ(NH₃-N)>3.0 mg/L)、高铁锰(ρ(总Fe)>12 mg/L，ρ(Fe²⁺)>8.0 mg/L，ρ(Mn²⁺)>3.0 mg/L)地下水出水锰和氨氮超标问题，开展两级曝气+两级过滤”净化工艺启动和铁锰氨氧化活性去除区位研究.两级生物净化工艺经133 d驯化培养启动成功，锰是影响启动周期长短的主要因素.启动成功后，氨氮去除负荷可达29.66 g/(m²·h)，锰去除负荷可达27.08 g/(m²·h)，产水量是单级净化工艺的2倍.铁锰氨氧化活性去除区位表明，铁在一级滤柱0~50 cm滤层内去除至痕量; 55.23%的氨氮在一级滤柱中去除，主要集中在滤层0~135 cm段，44.10%的氨氮在二级滤柱中去除，主要集中在滤层0~50 cm段.锰和氨氮在氧化去除过程中存在显著分级，ρ(NH₃-N)>2.25 mg/L时，会显著抑制锰氧化菌(MnOB)活性.锰在各级滤柱中的去除率和去除区位受进水氨氮质量浓度及滤速影响较大，滤柱启动成功后，仅有5.53%的锰在一级滤柱中去除，89.34%的锰在二级滤柱中去除.

Abstract:

The effluent manganese (Mn) and ammonia nitrogen (NH₃-N) concentration were found excessive when the low-temperature (5-7.8 ℃) groundwater containing high NH₃-N, iron (Fe) and Mn contents (NH₃-N>3.0 mg/L, Total Fe>12 mg/L, Fe²⁺>8.0 mg/L, Mn²⁺>3.0 mg/L) was purified by "one-stage aeration combined with one-stage filtration" process. To improve the purification efficiency, the start-up of "two-stage aeration combined with two-stage filtration" purification process and the oxidation-removal active sites (ORAS) of Fe, Mn and NH₃-N were investigated. Two-stage bio-purification process successfully started after 133 days and the start-up period was mainly related to the Mn content. The results showed that the removal capacity of NH₃-N and Mn was 29.66 g/(m²·h) and 27.08 g/(m²·h) respectively, and the water yield was a double of one-stage bio-purification process. According to the ORAS, Fe was removed to trace levels in the 0-50 cm section of the primary filter column, and the NH₃-N was removed by 55.23% and 44.10% respectively in the 0-135 cm segment of the primary filter column and 0-50 cm segment of the secondary filter column. There were significant removal classification between Mn and NH₃-N during the oxidation-removal process. The activity of Mn-oxidizing bacteria (MnOB) was significantly inhibited by NH₃-N in concentration greater than 2.25 mg/L. The removal ratio and ORAS of Mn in both filter columns were affected by the concentration of NH₃-N in raw water as well as the filtration rate. After a successful start-up, the Mn was removed by 5.53% and 89.34% respectively in the primary and secondary filter columns.