化學工廠廢水性質分析與氨氮改善處理流程規劃之研究

本研究主要因近年來環保觀念日益受到重視，因此法規對於氨氮的排放標準逐漸加嚴，針對目前許多工廠現有的設備並無法符合未來規劃的氨氮排放標準必須提出進一步之改善建議。所選擇的化工廠由於製造產品含有醯胺類，因此廢水中有高濃度有機氮，進而導致放流水中氨氮亦超過排放標準，而本研究則針對目前的廢水處理單元提出改善建議。　　規劃的改善方式首先針對目前處理單元一些水質項目進行14天的採樣分析，這些項目包括pH、COD、BOD、SS、氨氮、有機氮；另外亦包含放流水中的硝酸鹽氮以及活性污泥系統中的污泥容積指數，然後利用分析所得的結果針對各單元的處理效率以及廢水水質特性進行分析，並提出具體的改善方案。　　所得的結果顯示，由於有機氮轉換成氨氮，將導致放流水中的氨氮濃度偏高，整體的活性污泥操作系統可以藉由排泥量控制微生物生長，使COD、BOD與SS等項目符合放流水標準。針對氨氮的改善則建議可以考慮在處理單元增加氣提處理以符合目前放流水標準；若要符合加嚴後的標準，則建議增設加氯氧化單元，使氨氮濃度低於20mg/L。

關鍵字

氨氮廢水；化工廠；廢水水質特性；廢水處理改善

並列摘要

Since environmental protection concepts rose in recent years, the government regulations have gradually for ammonia nitrogen(NH3-N) got stricter emission standard. However, the current wastewater facilities in many chemical plants cannot process NH3-N in effluent to meet the demand in the future. High concentration of organic nitrogen exists in the wastewater causing ammonia nitrogen exceed the effluent standard. This study is to present suggestion of wastewater treatment to a chemical plant containing amides processes. A 14-day sampling has be performed, and then concentrations of target contaminants are measured in the current treatment unit including pH, COD, BOD, SS, ammonia nitrogen and organic nitrogen. It also includes nitrate nitrogen in the effluent and the sludge volume index in the activated sludge system. Analysis results were applied to understand removal ratios of target contaminants in each unit. The characteristics of wastewater were evaluated. Finally, improvement proposal focused on NH3-N and others was presented. 　　According to the results, organic nitrogen was converted to ammonia nitrogen, leading to the high concentration of ammonia nitrogen in the effluent. However, the growth of microorganisms in activated sludge process can be controlled by the amount of waste sludge. This can make COD, BOD and SS items meet the effluent.　For the improvement of ammonia nitrogen, it is recommended to consider adding air stripping process in treatment units to meet the current discharge water standard. If it is demanded to meet the stricter standards, it is recommended to add a chlorine oxidation unit to make the ammonia nitrogen concentration lower than 20mg/L.