The Treatment of Nitrogenous Wastewater from the Solar-Cell- Manufacturing Process Using a Membrane Bioreactor System
|Keywords:||固定式生物硝化技術(BioNET);側流式薄膜生物技術;氨氮硝化;厭氧脫硝;低碳氮比廢水;碳源;Biological New Environmental Technology (BioNET);Sidestream Membrane Bioreactor Technology;Nitrification;Denitrification;low C/N wastewater;Carbon Source|
在本研究薄膜生物程序試車運轉後，連續穩定操作達61天中；硝化槽進流水pH平均為 9.4，在添加鹼劑硝化後，出流水質pH平均為 6.8 具有相當穩定的控制結果；厭氧脫硝反應結果上，外加碳源之碳氮比控制平均於6.12時，氧化還原電位值可操作在-400 mV至-500 mV之間，此條件下經再曝氣槽處理後出流水氨氮及硝酸鹽氮濃度幾乎完全被去除；脫硝後pH平均為7.7不需額外添加酸鹼藥劑即可達排放標準； 在側流式薄膜生物技術應用上，維持穩定之薄膜產水通量與跨膜壓差控制，可推估實廠中薄膜產水通量34 ~38 L/m2-hr 操作下為保守之臨界通量控制，相對於沉浸式薄膜技術上有較大的產水通量效能。
本研究結果中顯示，此低碳氮比廢水氨氮去除率均可控制於 83% ~ 98% 之間，在適當的碳源添加控制下有極佳穩定的除氮效能表現，且能符合新竹科學園區下水道使用排放氨氮分級收費管制限值30 mg/L以下。|
In recent years, the rocketing development of industrial manufacturing such as semiconductor or optoelectronic industries in Taiwan has caused a large amount of wastewater being discharged into the environment. Ammonia is one of the main pollutants released from these kinds of wastewater. According to a survey from the Environmental Protection Administration, ammonia containing wastewater from optoelectronic industry and Science Park was 34% of total amount of wastewater produced. Because of its negative impacts on environment such as causing the oxygen depletion and eutrophication phenomenon, ammonia is regulated by Taiwan government and needed to be removed from the wastewater. In 2012, new standard for the ammonia concentration in the effluent from optoelectronic industry and Science Park was released, thus needing an improvement in treating ammonia containing wastewater. The wastewater from optoelectronic industry contains high concentration of ammonia but low concentration of carbon to nitrogen ratio; thus, carbon source is external added during the nitrification and denitrification processes. Among ammonia treatment technologies, membrane bioreactor becomes a candidate for the treatment of ammonia because of its high sludge retention time (SRT), low sludge production and low footprint. This study aims to use O/A/O+MBR process to treat the ammonia containing wastewater from the optoelectronic industry. Herein, the effect of internal carbon source on ammonia removal by O/A/O+MBR system was investigated. In addition, long-term operation of the O/A/O+MBR was observed. During 61 days operation, the average pH of the influent of the nitrification reactor was 9.4, while it was maintained around 6.8 at the effluent after pH adjustment. Oxidation Reduction Potential (ORP) of the reactor was in range of -400 mV - -500mV. Under these conditions, ammonia and nitrate were almost reduced. After denitrification process, the average pH of the reactor was 7.7; therefore, it was appropriate to discharge into the water receiving bodies. The flux of the cross flow MBR remained at 34-38 L/m2-h. The results from this study also found that the ammonia removal was 83% - 98% under low C/N ratio. Under appropriate carbon source addition, the ammonia concentration at the effluent of the bioreactor was lower than 30 mg/L of effluent standard.
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