- 期刊
溪流水體之硝化反應模式分析
The Nitrogen Removal Biokinetics of Suspended Nitrifiers in Streams
摘要
近年來由於工業，農業及家庭廢水，在未經有效之處理程序即排入天然水域中，造成水體的污染。廢水中之含氮化合物對水體的影響以造成水體溶氧降低，水質惡化，及導致湖泊，水庫之優養化最爲嚴重，而現有之野溪因排入廢水量增多也日漸受污染。本文以長期培養馴化之硝化性污泥，探討其在不同酸鹼值的情況下對不同氨氮濃度的去除效率，並進一步利用硝化菌對基質的削減，及硝化菌的攝氧活性求取其反應動力參數。硝化菌對氨氮之削減速率爲pH = 8＞ pH = 9＞ pH = 7，且在pH = 9時有明顯的氣提（stripping）現象產生。亞硝酸氮在pH = 8及pH = 9時有累積的現象，且在pH值越高時越明顯。本研究採用的基質抑制模式爲指數抑制模式，藉由此基質抑制模式得知亞硝酸菌在pH = 8時有最大的攝氧活性速率μ^* = 39.1mgO_2/gVSShr，其攝氧速率爲pH = 8＞ pH = 9＞ pH = 7。而硝酸菌則在pH = 8時有最大的攝氧活性速率μ^*= 20.2mgO_2/gVSShr，其攝氧速率爲pH = 8＞ pH 7＞ pH =9。利用攝氧活性的結果顯示，pH = 8時可以處理較高濃度之氨氮廢水，其最大的氨氮抑制濃度爲357.1mg/l。
並列摘要
The removal of ammonia nitrogen from natural streams is an important issue of water quality concerns since this pollutant is toxic to fishes, and can stimulate undesirable aquatic growths, which results in the eutrophication of natural waters. During the nitrification process, the dissolved oxygen in the water bodies is depleted and the water quality in the stream is deteriorated accordingly. In this study, the biokinetics of suspended nitrifiers, ie. Nitrosomonas and Nitrobacter, is explored by employing laboratory evaluations. The exponential inhibition model is adopted based on the experimental data. The maximum specific oxygen uptake rate (SOUR) is 39.1 mg O2/gVSShr for nitrosomonas at pH = 8, and the maximum specific oxygen uptake rate (SOUR) is 20.2 mg O2/gVSShr for nitrobacter at pH = 8. The SOUR sequence for nitrosomas is pH =8 ＞ pH =9 ＞ pH =7. On the other hand, the SOUR sequence for nitrobacter is pH =8 ＞ pH = 7 ＞ pH = 9. The activity of nitrobacter is inhibited for the cases of pH =9, and nitrite is accumulated under such conditions. The best operating condition for ammonia removal is thus at pH =8, and the inhibitive concentration is 357.1 mg/l which is higher than the cases at pH=7 and pH =9.