不同深度处理工艺再生水中余氯衰减规律及溶解性有机物变化特性比较

考察了余氯在不同深度处理工艺再生水中的衰减规律,并利用紫外-可见吸收差光谱和三维荧光光谱对余氯衰减过程的有机物变化进行了初步解析.结果表明,再生水中的余氯衰减迅速,加氯前0.5 h内的氯消耗占8 h内氯消耗的50%以上.混凝出水水样的余氯衰减速率大于超滤出水和臭氧出水.加氯后,混凝出水和超滤出水的紫外-可见吸收差光谱在230 nm和280 nm附近出现特征峰,表明余氯衰减过程中,水中具有不饱和键和生色团的物质被破坏.臭氧出水在波长230 nm附近出现特征峰.加氯使再生水的荧光强度减弱,混凝出水中腐殖质类物质荧光强度的降低程度大于超滤出水和臭氧出水,表明该类物质可能是影响余氯衰减速率的主要物质.

Comparison of residual chlorine decay in different reclaimed water and the relationship with the change in DOM

The chlorine decay rates in different reclaimed water samples were investigated, and DOM was characterized by UV-VIS absorption spectrum and 3D exciting-emission-matrix (EEM). Results showed that the residual chlorine decayed rapidly in three reclaimed water samples. The chlorine consumption had reached more than 50% in the first 0.5 h of the total 8 h. The decay rate was higher in coagulation effluent than the ones for the ultra-filtration and ozonation effluents. Two characteristic peaks near 230 nm and 280 nm were found in the UV-VIS differential absorption spectrums (DAS) of coagulation and ultra-filtration effluents after chlorination, which indicate that unsaturated bonds and chromophoric moieties were destroyed by the residual chlorine in the water. Only one characteristic peak near 230 nm was found in the spectrum of the ozonation effluent. The intensity of fluorescence decreased during chlorine decay. The extents of intensity of the humus substances were different in the three samples, while they were consistent with the chlorine decay rates. This indicated that the humus substances may be the main materials accounted for the chlorine decay in the reclaimed water.