以臭氧及活性碳程序處理水中有機氯農藥

Abstract

有機氯農藥因具高毒性，在環境殘留時間長，且傳統的淨水程序不易處理，所以必須開發高級處理程序以輔傳統程序之不足。有鑒於此，本研究利用臭氧及活性碳程序探討有機氯農藥去除的效能。在處理技術評估方面，臭氧對去除有機氯農藥之效能地特靈約為33%，相當有限。因而加入一些臭氧氧化之促進劑，如過氧化氫、紫外線，藉以提高水溶液中氫氧自由基的濃度，以加速反應之進行。O3/H2O2，程序中地特靈約可去除80%，O3/UV 程序中地特靈約可去除74%，而在臭氧與過渡金屬離子組合程序中，O3/Cu(Ⅱ)程序對地特靈之去除率更高達92%。 本實驗以Microtox測試系統之毒性，發現助溶劑丙酮經臭氧氧化後會使系統之毒性上升，而地特靈經臭氧氧化後之中間產物毒性亦有上升趨勢，最後以活性碳吸附會使系統之毒性降低。 本研究針對數種常見的活性碳，分析出多項之基本性質，並作一比較性之探討，此可能提供選用時之參考。在臭氧及活性碳程序中，實驗發現，殘餘臭氧會降低活性碳之吸附能力，因此系統設計時，應使進入活性碳過濾系統的臭氧保持低濃度，以維持活性碳之使用壽命。在成本分析方面，已從美國環保署取得成本預估模式，可藉以預估活性碳吸附及再生系統之各項成本，並尋求符合經濟效益之操作條件。

The residual ciriormated organic pesticides in water source is highly concerned recently because of its high toxicity and long retention time in our environment. It is found that the chlorinated organic pesticide is not easily removed by traditional water purification process, so more efficiency treatment method need to be developed. In this study, we tried to combined some processes(so called AOPs)of ozone, GAC, H2O2, UV and transition metals to treat those pesticides. In this experiment, we find that only using ozone to remove dieldrin gets a limiting efficiency, but if combing with the AOPs, better efficiency will be investigated. Comparing the perfonnance of those processes, we find the transition metal Cu2+ has an excellent promoting ability, and O3/UV process perform a good ability of mineralization. Microtox test is used to analyze the toxicity of dieldrin and its intermediates. We also find the toxicity of the cosolvent acetone will highly increase when it reacts with the ozone. Chlorine is detected by using IC and DPD, and about 47% of chlorine released from dieldrin is found. In O3/GAC process, we find ozone will affect the adsolption ability of GAC, therefore, ozone should be removed before the water flowing into GAC filter. Finally, we use a mathematical model which is got from the USEPA to make a cost analysis of GAC filter system and GAC regeneration system.