臭氧对有机物混凝的影响

采用PDA(Photometric Disperse Analysis)和有机物表观分子量分级、有机物化学极性分级技术从絮体形成过程、絮体表现、有机物分子水平变化等方面研究了臭氧预氧化对混凝过程的影响;并对比了不同混凝剂在预臭氧条件下的混凝过程和效率.结果表明:臭氧预氧化对混凝过程有复杂的影响,其剂量和水体有机物特征决定了其对混凝的整体影响效果.有机物分级显示,臭氧化对有机物结构有重要影响,导致有机物极性、亲水性组分含量大幅提高(36.7%),小分子量组分(<10×10³)大幅增高(100%左右);但总的DOC去除率不高(3.28%).对PACl而言,在中、低剂量(O₃/TOC<0.7)下,臭氧对絮体形成过程影响较小,但对絮体沉降性和浊度去除已经有阻碍作用.在中、高剂量下(O₃/TOC>0.7),对絮体形成有显著滞后,浊度、有机物去除效率下降.AlCl₃对臭氧化作用反应敏感,臭氧化在试验剂量条件下,对絮体形成和浊度、有机物去除都有明显的阻碍作用.

Effects of Pre-Ozonation on Organic Matter Coagulation

PDA(Photometric Disperse Analysis),apparent molecular distribution and fractionation of aquatic organic matters were performed.Formation and performance of flocs in coagulation processes were detected.And changes of aquatic organic molecular structure resulted from the influence of pre-ozonation were studied.Complicated effects of O₃ on organic matter coagulations were showed;dosage of O₃ and characteristics of aquatic organic matter were two of the major factors result in whole performance of O₃ on coagulation.Judged from results of fractionation,great influence was made by O₃,which increased fraction of more polarity and hydrophilic by 36.7% and fraction of molecule smaller than 10×10³ by 100% or so;but total removal of DOC was limited only 3.28%.When PACl was used as coagulant,less effect on floc formation was observed as O₃/TOC<0.7.With O₃ dosage increasing,floc formation was retarded more and more and removals of turbidity,DOC and UV₂₅₄ were all decreased.AlCl₃ performed badly than PACl under influence of O₃ in almost all the parameters detected in the study.It showed that PACl was superior to AlCl₃ when pre-ozonation were adopted.