以高級氧化法配合強化混凝處理染料廢水

Abstract

染料製程廢水中最主要的問題，就是廢水中含有很多高化學需氧量和色度的染料及中間體。這些有機分子結構相當的複雜並具有毒性，一般無法以生物有效的處理。本研究利用Fenton化學氧化與強化混凝，對實際染料廢水進行處理，探討染料製程廢水中所含有之懸浮固體、化學需氧量與色度的去除效率。 實驗過程先利用Fenton氧化法將廢水中的偶氮類芳香族化合物予以事先破壞，Fenton法產生之氫氧根自由基，可破壞染料中之難分解的大分子發色團有機物，迅速達到脫色效果，並可吸收水質水量的不穩定對生物處理所造成的衝擊，以便後段生物處理能充分發揮其功能，並進一步降低排放水COD。經比攝氧率實驗證實，原先抑制型之廢水經過氧化後毒性已被去除。 在混凝方面，經化學氧化後，引入「強化混凝』(Enhanced Coagulation)的觀念，尋求最佳的化學混凝條件，使懸浮顆粒、色度、重金屬、化學需氧量等皆能被有效去除、實驗結果顯示，Fenton法配合強化混凝，在適當的加藥劑量與操作條件下，化學需氧量與懸浮固體去除效率可達80%與95%以上，色度去除效率可達99%以上。

The mam problem arisen from dye wastewater treatment is that there are a lot of dye and intermediate compounds which have high chemical oxygen demand and color in wastewater. Those organic compounds processing large and complicated structures are well known to be unbiodegradable. In this study, a series of batch trials using Fenton oxidation method with enhanced coagulation were performed under different conditions to explore their effects on the removal efficiency of COD, SS, and color. Fenton oxidation process is the cheapest method among several advanced oxidation processes (AOP). The OH radicals made from Fenton reaction can break the double bonds in dye into smaller. compounds, effectively reduce COD concentration and let the small chemicals easy to treat by biological treatment later. The results of specific oxygen uptake rate indicate that the toxicity in wastewater is reduced after Fenton reaction. After Fenton reaction, we introduce a brand new concept "Enhanced Coagulation," to find out that how to efficiently remove color, chemical oxygen demand and suspend solids. The combination of Fenton process and enhanced coagulation is proved useful in the dye wastewater treatment. Under proper dosages and conditions, the removal efficiency of chemical oxygen demand and suspend solids can reach 80% and 95% respectively. The removal efficiency of color can reach as high as 99% or even higher.