活性污泥/接觸曝氣/MBR合併系統之處理功能研究

Abstract

摘 要 WG EGGS是家頗具規模的食品大廠，它們面臨著不同的廢水處理挑戰。WG EGGS面臨來自洗蛋污水、蛋液、雞隻排泄物和生活污水的高濃度有機廢水，水質變化受每日雞蛋破損量的影響。為了解決水中蛋液難以均質化的問題，該廠在現有的接觸曝氣處理系統中增設活性污泥和(membrane bioreactor, MBR)處理單元，形成活性污泥/接觸曝氣/MBR合併處理系統，因有懸浮性及附著性微生物，含好氧菌、兼氧菌及厭氧菌，生物相多，系統穩定，耐環境衝擊而達到水質的預期處理效果。儘管MBR被視為最具前途的廢水處理技術之一，但仍然存在成本高和膜阻塞的問題。在這種合併系統中，透過接觸曝氣池的生物濾材過濾，有效的解決了膜積垢的問題，並且在COD、BOD、SS和油脂的平均去除率方面都取得了良好的處理效果，同時也降低操作和設備費用。經此系統處理過後懸浮固體的平均去除率為97.7%，COD的平均去除率為94.5%，BOD的平均去除率為96.7%，油脂的平均去除率為92.1%。而進流水COD、BOD、SS及油脂之平均值加減標準偏差分別為(567.6±473.7) mg/L、(282.5±252.4) mg/L、(390±689.8) mg/L、(30.5±27) mg/L，經此系統處理後標準放流水平均值加減標準偏差分別下降至(30.9±14.8) mg/L、(9.2±4.6) mg/L、(8.7±9.8) mg/L、(2.4±2.2) mg/L，在進流濃度變化大的情形下出流水水質還是可以維持穩定，證明此系統是非常穩定且很能承受環境衝擊的。由WG EGGS廠各池之水質分析及(next generation sequencing, NGS) 探討可知各池生物相都很多發現有硝化能力的菌種與脫硝能力的菌種分布在各槽中，對各項水質都有良好的去除能力對於總氮總磷都有一定的處裡效果。COD、BOD、油脂、總氮、氨氮、有機氮、總磷及溶解性有機碳在05:00、08:00和11:00三個時間段的水質平均去除率分別為以下數據，去除率分別為COD 94% 、BOD 97% 、油脂 96% 、總氮46% 、氨氮 86%、有機氮 88%、總磷 65%、溶解性有機碳 97%。 對於總氮總磷有一定的除效率放流水達到再生水標準，各池硝酸鹽氮及亞硝酸鹽氮數值的高低變化狀況發現，各池都有有機氮變成氨氮再好氧硝化成亞硝酸鹽氮、硝酸鹽氮在開始生物反應以後由為明顯，總氮平均減少7 mg/L、氨氮平均減少5.5 mg/L、有機氮平均減少6.9 mg/L、硝酸鹽氮平均上升5.4 mg/L。平均去除率總氮平均減少46%、氨氮平均減少87%、有機氮平均減少88%、硝酸鹽氮平均上升93%。發現本廠相對於總磷有一定的處理效果平均去除量為1.4 mg/L 去除率65%。處理系統內生物相多且平均生物多樣化生存含竟耗氧、厭氧、兼氧，代謝方式硝化、脫硝，生存樣態附著、懸浮式微生物。

Abstract WG EGGS is a large-scale food factory facing various wastewater treatment challenges. WG EGGS deals with high concentrations of organic wastewater from egg washing, egg liquid, chicken excrement, and domestic sewage, with water quality varying based on the daily egg breakage rate. To address the difficulty in homogenizing egg liquid in the water, the plant added activated sludge and a (membrane bioreactor, MBR) treatment unit to the existing contact aeration treatment system, forming an activated sludge/contact aeration/MBR combined treatment system. Due to the presence of suspended and attached microorganisms, including aerobic, facultative anaerobic, and anaerobic bacteria, the system has a diverse biological community, ensuring stability and resistance to environmental impacts, achieving the expected water quality treatment effects. Although MBR is considered one of the most promising wastewater treatment technologies, it still faces high costs and membrane fouling issues. In this combined system, biological media filtration in the contact aeration tank effectively solves the membrane fouling problem and achieves good treatment effects in terms of average removal rates for COD, BOD, SS, and grease, while also reducing operating and equipment costs. After treatment by this system, the average removal rates were 97.7% for suspended solids, 94.5% for COD, 96.7% for BOD, and 92.1% for grease. The average values ± standard deviations for influent COD, BOD, SS, and grease were (567.6±473.7) mg/L, (282.5±252.4) mg/L, (390±689.8) mg/L, and (30.5±27) mg/L, respectively. After treatment, the effluent average values ± standard deviations decreased to (30.9±14.8) mg/L, (9.2±4.6) mg/L, (8.7±9.8) mg/L, and (2.4±2.2) mg/L, respectively. Despite significant variations in influent concentration, the effluent water quality remained stable, demonstrating the system's stability and resilience to environmental impacts. Through water quality analysis of various tanks at the WG EGGS plant and (next generation sequencing, NGS), it was found that each tank had a diverse biological community, including species with nitrification and denitrification capabilities, contributing to effective removal of various pollutants. The water quality average removal rates for COD, BOD, grease, total nitrogen, ammonia nitrogen, organic nitrogen, total phosphorus, and dissolved organic carbon at 05:00, 08:00, and 11:00 were 94%, 97%, 96%, 46%, 86%, 88%, 65%, and 97%, respectively. The system achieved certain efficiencies in removing total nitrogen and total phosphorus, with effluent meeting reclaimed water standards. The variations in nitrate nitrogen and nitrite nitrogen values indicated significant transformations of organic nitrogen to ammonia nitrogen, followed by aerobic nitrification to nitrite nitrogen and nitrate nitrogen. The average reductions were 7 mg/L for total nitrogen, 5.5 mg/L for ammonia nitrogen, 6.9 mg/L for organic nitrogen, and an average increase of 5.4 mg/L for nitrate nitrogen. The average removal rates were 46% for total nitrogen, 87% for ammonia nitrogen, 88% for organic nitrogen, and an increase of 93% for nitrate nitrogen. The system also showed effectiveness in total phosphorus removal, with an average reduction of 1.4 mg/L and a removal rate of 65%. The treatment system exhibited high biological diversity, including competitive aerobic, anaerobic, and facultative anaerobic microorganisms, with metabolic pathways involving nitrification and denitrification, and survival modes including attached and suspended microorganisms.