以ORP控制含磷污泥貯存過程磷再釋出之可行性研究

A study of phosphorus release control by ORP meter for EBPR sludge in storage stage

周家豪(Chia-Hao Chou)

指導教授 ： 莊順興

朝陽科技大學/理工學院/環境工程與管理系/碩士(2009年)

摘要

在EBPR程序所產生的含磷污泥，一般貯存於污泥貯存槽中，於貯存槽中未經曝氣時會漸漸達到厭氧狀態，此時污泥會有磷再釋出至水體的現象，釋出之磷經由脫水濾液迴流至EBPR系統，增加進流之磷負荷，終將導致系統除磷失敗。因此本研究主要利用電腦線上監測的方式，搭配氧化還原電位(Oxidation-Reduction Potential, ORP )控制，了解含磷污泥在貯存過程釋磷情形與ORP之相關性，期望以ORP作為控制指標，降低污泥再度釋磷之現象。
以ORP及pH作為指標於厭氧貯存120小時之批次實驗中顯示，中磷系統濃縮污泥在4小時內已達釋磷穩定狀態，高磷系統濃縮污泥則在7小時到達釋磷穩定狀態，顯示出不同磷負荷系統之污泥展現不同釋磷特性。當正磷酸鹽達最大飽和釋磷量後，中、高磷系統濃縮污泥釋磷特性並不能反應在ORP之變化上，如果欲以ORP作為控制指標，可以從初始0小時至最大飽和釋磷量(第48小時)這段時間去找尋ORP與正磷酸鹽相關之控制範圍。
在中、高磷系統濃縮污泥厭氧貯存48小時之批次實驗中發現，正磷酸鹽的釋出情形，可能受兩種因素影響，包括：(1)厭氧程度 (2)基質的多寡(小分子有機物)，兩者都會影響正磷酸鹽之釋出情形。
正磷酸鹽釋出情形之相關性反應順序為SS削減、COD溶出、ORP下降，當細胞水解後造成貯存槽之SS減少後，會溶出大分子有機質，此時貯存槽若為穩定厭氧狀態，則磷蓄積菌會利用由細胞水解之小分子有機物，作為碳源產生釋磷現象。以中、高磷系統濃縮污泥批次實驗而言，顯示SS削減明顯較常發生於ORP達-200mV時、而當ORP達到-300 mV以下且COD濃度約為100 mg/L以上時，會開始產生明顯之釋磷現象。
控制因子之研究顯示，以中磷濃縮污泥厭/好氧交替(Run-M-AO2)控制下，有較佳之效益，最終至120小時之釋磷量減少百分比為67%，高磷濃縮污泥之厭/好氧交替(Run-H-AO1)控制則可達55%之釋磷減少量，有較好效益。
添加氧化劑(硝酸鹽)控制釋磷之實驗結果顯示，中磷濃縮污泥添加氧化劑(Run-M-N2)控制，有較好的效益，最終至120小時之釋磷量減少百分比為47%，高磷濃縮污泥(Run-H-N1)之釋磷量減少百分比為24%。

關鍵字

厭氧釋磷 ； 氧化還原電位 ； 厭好氧交替 ； 硝酸鹽

並列摘要

The prupose of this research aim to discussing the interactivity and relationship between phosphorous release of sludge and ORP(Oxidation-Reduction Potential).
In 120 hours anaerobic operation of batch experiment. The middle phosphorus SBR system has been steady state whthin 4 hours, and high phosphorus SBR system has been steady state whthin 7 hours . It mean different phosphorus loading has different characteristic. In the middle and high phosphorus SBR system of anaerobic operation in 48 hours batch experiment, phosphorus release can be affected two factors, (1) anaerobic degree , (2) how many substrate.
Phosphorus release is under following sequence: SS reduce, COD to dissolve, ORP to drop. While the cell hydrolysis in sludge storage tank , it could produce dissolved macro molecule from organisms. While the anaerobic degree be steady state, PAOs(Polyphosphate accumulating organisms) will use the hydrated of small molecule as carbon source for phosphorus release. In the middle and high phosphorus SBR system of anaerobic operation in 48 hours batch experiment, it shown that SS decrement has ORP under -200 mV. When the ORP under -300 mV and COD concentration was 100 mg/L, the PAOs will getting phosphorous release.
The phosphorus SBR system of anaerobic/ aerobic operation in 120 hours batch experiment, the experiment of Run-M-AO2 show that the phosphorus release was reduce about 67 %. The experiment of Run-H-AO1 demonstrated that the percentage of phosphorus release was reduced 55 %.
The phosphorus SBR system of addition nitrate operation in 120 hours batch experiment, the experiment of Run-M-N2 for phosphorus release was reduced 47 %. The experiment of Run-H-N1 for phosphorus release was reduced 24 %.

並列關鍵字

Anaerobic phosphorus release ； Nitrate ； Oxidation-Reduction Potenatal ； Anaerobic/aerobic operation

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