| 摘要: | 薄膜生物處理技術 (Membrane bioreactor, MBR) 為廢水處理技術中成長最快的技術之一。 MBR 同時具有很多的優點，包括佔地面積和反應器體積小、污染物去除效率好、污泥產量少及出流水水質高等多項好處。正常狀況下，薄膜生物反應器中會進行大量的曝氣行為，主要是為系統中的微生物供給氧氣及使用氣體沖刷薄膜表面。然而，該系統有一個明顯的缺點就是此系統中無法有效除氮。 Yeom et al. (1) 等人的研究顯示在 A2O-MBR 的操作環境中是有利於磷的去除，並不是氮的去除。本研究的目的是好氧MBR前一槽添加生物載體 (Biocarrier-aerobic-MBR process, BAMBR)，以兩槽代替 A2O-MBR 的三槽系統，並試圖提升好氧 MBR 去除氮的能力。在本研究中，探討兩個不同的操作條件下，污泥迴流率和 COD/N 比在 BAMBR 中去除污水有機物及氮之效益評估。本研究中，該系統分為兩個槽體，其一為缺氧槽，其二為 MBR 槽，負責固液分離。本研究使用合成污水為進流水，並使用連續進流式的生物載體-好氧 MBR (BAMBR) 替代 A2O-MBR，探討在合成廢水中的有機物及氮的去除效益。本系統進行了5個階段和不同的操作條件，共進行了260天。 (1) 缺氧槽(槽中置放海綿)與 MBR 槽的迴流比為3Q (2) 迴流比保持3Q並額外添加鹼度 (NaHCO3) (3) 缺氧槽(改變海綿置放方式)與 MBR 槽的迴流比為3Q，額外添加鹼度 (NaHCO3) 並使用 (NaOH) 調整其 pH (4) 缺氧槽 (海綿) 與 MBR 槽的迴流比為2Q，額外IV添加鹼度 (NaHCO3) 並使用 (NaOH) 調整其 pH (5) 缺氧槽 (海綿) 與 MBR 槽的迴流比為2Q，額外添加鹼度 (NaHCO3) 、並使用 (NaOH) 調整其 pH 、調整 COD/N 比至7。本研究中，在 (迴流比為2Q及 COD/N 比為7) 的操作條件下，TCOD、SCOD、氨和 TN 的去除率為100%、100%、100%和85%。 MBR 槽中氨的濃度及缺氧槽中硝酸鹽和亞硝酸鹽的濃度在檢測中都非常的少，這表示在此條件下可以達到完全的硝化作用和高效的脫硝作用。此外，海綿有效地減少了薄膜的阻塞狀況，讓薄膜的使用時間增長，最長在55天內沒有更換及清洗薄膜。污泥的增加讓缺氧槽及 MBR 槽的有機負荷逐漸增加，並縮短薄膜使用時間，而且導致槽中的微生物產生更多的胞外聚合物 (EPS)。
Biological processes integrated with membrane separation are one of the fastest growing technologies in the wastewater treatment. MBR has many advantages include small footprint, reactor volume requirement, less sludge production and high effluent quality in term of nutrient removal. Normally, intensive aeration is carried out in a submerged MBR for supplying oxygen to microorganisms and scouring of the membrane surface. However, one obvious drawback in the use of intensive aeration is poor removal of nitrogen in the submerged MBR. An aerobic, anoxic and aerobic-membrane bioreactor (A2O-MBR) system was applied in laboratory scale by Yeom et al. (1), which the study seemed to indicate that the operating condition was advantageous for phosphorus removal, not nitrogen. By this way we try to find an alternative related to a hybrid MBR system to have the function for organic and nitrogen removal. The main goal of this study was to investigate a biocarrier-aerobic-MBR process in place of A2O-MBR process. Two different operating conditions, sludge recycling rate and COD/N ratio for removing organic and nitrogen from domestic wastewater, were assessed in this study.The biocarrier-aerobic-MBR process has two compartments including an anoxic and an oxic biological reactor with integrated membrane for solid-liquid separation. Domestic wastewater may contain a considerable amount of nutrient and organic matter. The research was conducted to investigate the possibility in using continuous biocarrier-aerobic-MBR process in place of A2O-MBR process for treating synthetic domestic wastewater by studying its performance in terms of organic and nitrogen removal. The biocarrier-IIaerobic-MBR process was operated for 260 days with 5 stages and differentoperating conditions. (1) anoxic (sponge)-MBR with 3Q recirculation rate (2) anoxic (sponge)-MBR with 3Q recirculation rate and extra alkalinity (NaHCO3) addition (3) anoxic (new model sponge)-MBR with 3Q recirculation rate, extra alkalinity (NaHCO3) addition and pH (NaOH) adjustment (4) anoxic (new model sponge)-MBR with 2Q recirculation rate, extra alkalinity (NaHCO3) addition and pH (NaOH) adjustment (5) anoxic (new model sponge)-MBR with 2Q recirculation rate, extra alkalinity (NaHCO3) addition, pH (NaOH) adjustment and adjusted COD/N ratio to 7.The results showed that the highest TCOD, SCOD, ammonia and TN removal of 100%, 100%, 100% and 85% can be achieved under a specific operating mode (sludge recycling rate of 2Q and COD/N ratio of 7). The concentration of ammonia in MBR tank, nitrite and nitrate in anoxic tank were almost non-detected, which indicated that this operating condition can reach complete nitrification and high efficiency of denitrification. The sponge addition in the anoxic tank was functional for reduce membrane fouling which the result show that sustainable operation up to 55 days was maintained without any cleaning. The biomass in anoxic and MBR tank increase gradually when organic loading increased, which cause of microorganisms produced more extra-cellular polymeric substance (EPS) and effect to membrane fouling in this study. |
