多种类新污染物在高效溶气气浮工艺中的去除率探究

Exploration on the Removal Efficiency of Various Classes of Emerging Contaminants in High Rate Dissolved Air Flotation

新污染物由于其具有在水环境中频繁检出、长期暴露对人体可能存在危害、以及部分难以去除的特性,近来被社会广泛关注。高效溶气气浮是饮用水厂常见的前处理工艺,有必要探究其对不同类型新污染物的去除能力。研究建立了一套中试试验系统,比较了单独使用高效溶气气浮和前臭氧联用高效溶气气浮对新污染物的去除效果。臭氧的投加根据供水中的溶解性有机碳决定。试验结果表明,高效溶气气浮对新型污染物的去除率一般低于50%,且对扑热息痛、卡马西平、吉非罗齐、磷酸三(2-氯乙基)酯(TCEP)、17β-雌二醇和碘普罗胺未见去除效果。而采用预臭氧联用高效溶气气浮工艺时,扑热息痛、卡马西平、磺胺甲恶唑、甲氧苄啶和17β-雌二醇的去除率明显提高(>99%),但吉非罗齐、TCEP、可替宁、咖啡因和碘普罗胺去除效果依然有限(<50%或出水浓度无明显变化)。试验证明,单独使用高效溶气气浮虽然对新污染物去除效果有限,但是结合前臭氧工艺可以显著提高部分新污染物的去除效果,可以最大化去除效率。

Recently,emerging contaminants has raised extensive concern in the society,due to their high detection frequency in the aquatic environment,potential adverse effects to human health from long-term exposure,and the resistance to the treatment processes of some compounds.High-rate dissolved air flotation is a common pre-treatment process in drinking water treatment plants.It is necessary to investigate the removal efficiency of various classes of emerging contaminants in this treatment process.This study established a pilot-scale system.The removals of emerging contaminants were compared in high-rate dissolved air flotation alone and in pre-ozonation in combination with dissolved air flotation process.The dosage of ozone was determined based on the dissolved organic carbon in the influent.The results indicated that the removal efficiency in high-rate dissolved air flotation was generally less than 50%.Moreover,no removal was observed for paracetamol,carbamazepine,gemfibrozil,tris(2-chloroethyl)phosphate(TCEP),17β-estradiol,and iopromide.On the other hand,by using pre-ozonation together with high-rate dissolved flotation,the removal of paracetamol,carbamazepine,sulfamethoxazole,trimethoprim,and 17β-estradiol was significantly improved(>99%).However,the removal of gemfibrozil,TCEP,cotinine,caffeine,and iopromide was still limited(<50%or effluent concentration did not show significant change).The results indicated that high-rate dissolved air flotation alone revealed limited removals.However,with the combination of pre-ozonation the removals significantly enhanced for some of the emerging contaminants,therefore maximized their treatability.