煉油廠放流水氨氮及硝鹽氮改善實例

A Real Case of Ammonia and Nitrate Removal Improvement in Refinery Wastewater Treatment

張士元(Shih-Yuen Chang) ； 涂茂園(Mao-Yuan Tu) ； 蕭愛芬(Ai-Fen Hsiao) ； 曹蓮桂(Lien-Kuei Tsao) ； 黃冬梨(Tung-Li Huang)

《石油季刊》 49卷2期 (2013/06) Pp. 91-110

摘要

環保署於2012年7月1日實施新的石油化學業放流水標準（環署水字第1000103848號令），在原有管制項目外，增加氨氮、6種揮發性有機物及6種塑化劑等，共13項新的管制標準。中油公司有三座煉油廠及一座石化廠，檢討製程，與上述新管制標準有關的項目為：氨氮、苯及乙苯。自2010年起，為因應新的放流水管制標準，進行定期的採樣追蹤，發現：（1）廢水只要經過既有的好氧生物處理，放流水中苯及乙苯含量皆小於0.001 mg/L，遠低於管制值之0.05 mg/L 及0.4 mg/L。（2）控制pH＝7～8及DO＝2.5～3.5 mg/L，可以得到良好的氨氮的去除效果，使得氨氮小於3.0 mg/L。（3）氨氮及硝酸鹽氮在好氧生物處理系統中，為反應物與產物的關係，因此當廢水氨氮濃度高而且硝化效率良好時，會造成硝酸鹽氮增高，甚至超過原有的管制標準。經過一番文獻與實廠探討研究，直接將既有的全好氧生物處理系統，改為A/O（Anoxic/Oxic）操作模式：將前端槽體改為缺氧槽、串聯後續曝氣槽、增加內循環或迴流量、調整溶氧及pH…等，以增加生物脫氮功能。改善後，立即看到明顯的脫氮效果，除了原有管制項目如COD、Phenols、SS、透視度…等，都維持良好的水質外，氨氮、硝酸鹽氮及其新增項目，也都符合2012年新的管制標準。是一個不需要增加設備投資費，即可獲得良好成果的廢水處理改善實例。

關鍵字

放流水標準 ； 氨氮 ； 好氧生物處理 ； 硝化及脫氮

並列摘要

New effluent standards of petrochemical industry issued by Environmental Protection Administration, adding 13 new restricted components including ammonia nitrogen, volatile organic compounds and plasticizer became effective on July 1, 2012. Three refineries and one petrochemical plant of CPC were subjected to the new regulation due to the ammonia nitrogen, benzene and ethylbenzene released from relevant processes. In order to comply the new regulation, effluents have been monitored periodically since 2010 and the studies indicated that: (1) the concentration of benzene and ethylbenzene could be kept below 0.001mg/L via the present aerobic biological treatment system, far less than the regulation limit, 0.05mg/L and 0.4mg/L respectively. (2) effective removal of ammonia nitrogen (＜3.0mg/L) could be achieved by proper control of pH (7-8) and DO (2.5-3.5mg/L) management. (3) when effluents contained high ammonia nitrogen, the nitrification efficiency increased with formation of nitric salts in aerobic biological treatment system. Modification of the aerobic biological treatment into Anoxic/Oxic (A/O) system allowed significant improvements in nitrification and de-nitrification efficiency, which complied with the new regulatory standards of 2012. A real case study of ammonia and nitrate removal was demonstrated.

並列關鍵字

Effluent Standards ； Ammonia Nitrogen ； Aerobic Biological Treatment ； Nitrification & De-nitrification