臭氧-紫外预处理对高有机物原水混凝效果的影响

以腐殖酸为模型污染物,分别考察了臭氧氧化、紫外照射及臭氧-紫外联合预处理过程对高有机物原水混凝性能的影响.结果表明,3种预处理方式均对原水中的溶解性腐殖酸具有明显的矿化作用.紫外及臭氧-紫外联合预处理还对后续的混凝过程具有强化作用.随着臭氧投量的增加和紫外照射时间的延长,混凝过滤出水的TOC和浊度呈明显下降趋势.当臭氧浓度(O3/C)达到9.0 mg/mg时,预处理对腐殖酸的去除率可以达到47%,过滤出水TOC含量为3.5 mg/L,浊度为2.6 NTU;紫外光照射3 h可去除原水中52%的溶解性有机物,其出水TOC为2.0 mg/L,浊度低于1.0 NTU.臭氧-紫外联合预处理后的混凝效果要明显优于二者单独作用的系统.在联合预处理系统中,当预臭氧浓度(O3/C)为1.0 mg/mg紫外照射时间为1 h时,过滤出水TOC为2.6 mg/L,且浊度低于1.0 NTU.不同预处理条件下的矿化作用主要是通过.OH实现的,同时.OH还对溶解性腐殖酸的团聚结构产生破坏作用,使其稳定性降低,从而促进了混凝过程对有机物的去除.

Effect of Ozone-UV Pretreatment on Coagulation of Raw Water with High Organic Matter

Humic acid as a model pollutant, this paper aims to evaluate the effect of ozonation, ultraviolet irradiation and ozone-UV (UltraViolet) pretreatment process on the coagulation performance of raw water with high organics. The results indicated that three kinds of pretreatment had obvious mineralization on soluble humic acid in the raw water, and UV and ozone-UV pretreatment had a strengthening effect on the later coagulation process. With the increase of adding ozone dose and extension of UV irradiation, a decline in both content of TOC and turbidity were observed. Under the ozonation pretreatment process, when the concentration of ozone dose (O₃/C) was 9.0 mg/mg, 47% of humic acid could be removed by pretreatment, the content of TOC and the turbidity of the filtrated water was 3.5 mg/L and 2.6 NTU, respectively. With the UV pretreatment process, after 3 h UV irradiation, 52% of soluble organic matter could be removed by pretreatment, and the content of TOC and the turbidity of the filtrated water were 2.0 mg/L and 1.0 NTU, respectively. Furthermore, the UV/O₃ combined system was better than separate system. The optimum in combined pretreatment process was that the concentration of ozone dose (O₃/C) was 1.0 mg/mg, the time of UV irradiation was 1 h, the TOC of the filtrated water was 2.6 mg/L and the turbidity of that was less than 1.0 NTU. The mineralization effect under various pretreatment processes was achieved by the oxidation of ·OH, and at the same time the construction of humic acid was changed by pre-oxidation. As a result, the stability of the Reunion construction of humic acid was reduced which promoted the removal of the organic matter during the coagulation process.