National Research Center, Water Pollution Research Dept. El-tahrir St., Dokki, P.O. Box 12622, Cairo, Egypt.
J Environ Manage. 2010 May;91(5):1183-92. doi: 10.1016/j.jenvman.2010.01.010. Epub 2010 Feb 6.
The performance of polyurethane rotating discs (RBC-1) versus polystyrene rotating discs (RBC-2) for the treatment of an up-flow anaerobic sludge blanket (UASB) reactor effluent fed with domestic wastewater was investigated. Both RBC units were operated at the same organic loading rate (OLR) of 10.5 gCOD/m(2) d. and a hydraulic retention time (HRT) of 2.5 h. The residual values of COD fractions (COD(suspended), COD(colloidal) and COD(soluble)) in the treated effluent of RBC-1 and RBC-2 were similar. However, the removal efficiency of ammonia in the RBC-1 (87 +/- 4%) was significantly higher than that found for RBC-2 i.e. 24 +/- 6%. Moreover, RBC-1 achieved a substantial removal efficiency of 99.0 +/- 1% for Escherichia coli (E. coli), while RBC-2 removed 91.2 +/- 0.3%. Based on these results, optimization of RBC-1 treating UASB reactor effluent was extensively performed. The RBC-1 was operated at an OLR's of 4.0, 11 and 23 gCOD/m(2) d. The results obtained showed that increasing the OLR from 11.0 to 23.0 gCOD/m(2) d and decreasing the HRT from 2.5 to 1.25 h significantly declined the effluent quality of COD(total) and ammonia. However, the residual values of COD(total) and ammonia remained unaffected when increasing the OLR from 4.0 to 11.0 gCOD/m(2) d and by decreasing the HRT from 5 to 2.5 h. Bacteriological examination showed that the mean residual count of E. coli remained at a level of 10(4)/100 ml, in the effluent of RBC-1 independent on the imposed HRT. Accordingly, it is recommended to operate RBC-1 for treatment of anaerobically pre-treated sewage at an OLR of 11 gCOD/m(2) d and an HRT of 2.5 h. A feed-less (ammonia limitation) period of 9.0 days followed by 9.0 days feeding with high OLR of 26 gCOD/m(2) d. (raw sewage) was investigated to elaborate, if the nitrifiers of the RBC-1 are capable to convert ammonia to nitrate after totally 18 days when retuning back to the normal operating conditions. The results of the experiment clearly show a strong and immediate detrimental effect of imposing high OLR of 26 gCOD/m(2) d on the nitrification process in the nitrifying RBC unit. However, after returning back to the original OLR of 10.6 gCOD/m(2) d, the nitrification efficiency in the RBC unit was recovered within 2-3 days.
研究了用于处理上流式厌氧污泥床（UASB）反应器出水的聚氨酯旋转盘（RBC-1）与聚苯乙烯旋转盘（RBC-2）的性能。两个 RBC 装置均在相同的有机负荷率（OLR）10.5 gCOD/m(2) d 和水力停留时间（HRT）2.5 h 下运行。RBC-1 和 RBC-2 处理后出水中 COD 分数（COD(suspended)、COD(colloidal) 和 COD(soluble)）的残留值相似。然而，RBC-1 中氨的去除效率（87 +/- 4%）明显高于 RBC-2 即 24 +/- 6%。此外，RBC-1 对大肠杆菌（E. coli）的去除效率达到了 99.0 +/- 1%，而 RBC-2 则为 91.2 +/- 0.3%。基于这些结果，对 RBC-1 处理 UASB 反应器出水进行了广泛的优化。RBC-1 的 OLR 分别为 4.0、11 和 23 gCOD/m(2) d。结果表明，将 OLR 从 11.0 增加到 23.0 gCOD/m(2) d 和将 HRT 从 2.5 减少到 1.25 h 会显著降低 COD(total)和氨的出水质量。然而，当 OLR 从 4.0 增加到 11.0 gCOD/m(2) d 并将 HRT 从 5 减少到 2.5 h 时，COD(total)和氨的残留值不受影响。细菌学检查表明，无论施加的 HRT 如何，RBC-1 出水中大肠杆菌的平均残留数均保持在 10(4)/100 ml 的水平。因此，建议在 OLR 为 11 gCOD/m(2) d 和 HRT 为 2.5 h 的条件下，使用 RBC-1 处理厌氧预处理污水。研究了为期 9.0 天的无进料（氨限制）期，随后以 26 gCOD/m(2) d（原污水）的高 OLR 进料 9.0 天，以探讨 RBC-1 的硝化菌在总共 18 天后是否能够将氨转化为硝酸盐，当重新回到正常运行条件时。实验结果清楚地表明，在高 OLR 26 gCOD/m(2) d 下对硝化 RBC 单元中的硝化过程产生强烈和直接的不利影响。然而，当回到原始 OLR 10.6 gCOD/m(2) d 时，RBC 单元中的硝化效率在 2-3 天内恢复。
