Research and development of an on-line monitoring instrument for preventing wastewater treatment plant from damage by toxic materials invasion

[[abstract]]本研究為自行研發毒性物質入侵線上監測系統，已初步完成一套線上OUR(oxygen uptake rate)監測系統，此系統主要介面為利用Visual Basic軟體撰寫程式，並透過RS232連接外部電路板進行控制，目的藉微生物於不同毒性物質中之攝氧率作為分析參數，並規劃實驗探討不同有毒重金屬物質對活性污泥系統中微生物攝氧率之影響。 系統建構初期規劃不同污泥稀釋比進行測試，以了解污泥稀釋後對OUR之影響，並從中找出系統缺失加以改善。由不同污泥之稀釋比測試結果發現，當稀釋比達5：1時OUR值已明顯受到影響，因污水濃度過低不易測得準確OUR值。且在整個測試過程中發現突波現象，經檢討改善後已加強DO電極清洗動作，防止電極干擾情形，並於RS232傳輸過程中增加硬體交握控制，防止雜訊干擾。 在外加毒性物質入侵測試方面，結果顯示OUR之抑制率隨重金屬銅濃度增加而增加，當添加濃度達100ppm及150ppm時抑制率皆為70%，已達最大抑制百分比。其抑制百分比曲線符合一階反應，抑制率與銅金屬濃度間關係為OURI =（OURImin – OURImax）‧ + OURImax。[[abstract]]This research developed an on-line monitoring system of oxygen uptake rate (OUR) for preventing toxic substances invasion. This system mainly used the software of Visual Basic to compose the program, and troughed the RS232 to connect to the exterior electric circuit board for controling this system. The microbial oxygen uptake rates was used as the analysis parameter for measuring toxic matters invasion, and several experiments had been conducted in this study to discuss the influence of different virulent heavy metals on microbial oxygen uptake rates of the activated sludge. In the initial period of the study, different sludge dilution ratios experiments were carried on to understand the variations of OUR, find the system mistakes out, and improve them. It was found that dilution ratio larger than 5: 1 was unadequate for measuring OUR variation because the sewage concentration was too low to obtain the accurate value of OUR. Surge phenomenon was found in the test periods, and two methods were used to solve this problem. Firstly, the clean of the DO electrode was promoted to prevent the electrode from the disturbance. Secondly, the hardware junction in the RS232 transmission process was increased to avoid other signal disturbance. For the tests of toxic metals invasion, the result showed that the inhibition of OUR increased with the increase of the metal copper concentration. The inhibition percentage was near 70% while the concentration was higher than 100ppm. It was the maximum inhibition percentage. The inhibition kinetic could be modeled by first-order reaction.[[note]]碩