基于钙矾石沉淀法的长链二元酸生产废水预处理工艺  

Pretreatment process of long chain dicarboxylic acid wastewater based on anettringite precipitation method

作　　者：陈霖 曹越 张仁忠 王庆宏[1] 李琢宇 陈春茂[1] CHEN Lin;CAO Yue;ZHANG Renzhong;WANG Qinghong;LI Zhuoyu;CHEN Chunmao(State Key Laboratory of Heavy Oil Processing,College of Chemical Engineering and Environment,China University of Petroleum,Beijing 102249,China;Jinanruidong Industrial Co.Ltd.,Jinan 250101,China)

机构地区：[1]中国石油大学(北京)化学工程与环境学院,重质油国家重点实验室,北京102249 [2]济南瑞东实业有限公司,济南250101

出　　处：《环境工程学报》2023年第7期2169-2180,共12页Chinese Journal of Environmental Engineering

摘　　要：为避免长链二元酸生产废水中高浓度的总磷和硫酸盐对石化企业污水处理系统造成冲击,利用钙矾石沉淀法同步去除高浓度的总磷和硫酸盐,设计3因素3水平正交实验,探究了钙盐投加量、铝盐投加量和pH对污染物去除效果的影响,并优化工艺参数;利用GC-MS探究预处理前后废水有机污染组分的变化;利用XRD和XRF分析沉淀副产物的物质组成,并通过离子溶出实验探究沉淀副产物的可再利用潜力。结果表明:CaCl_(2)-PAC体系对污染物的去除效果优于Ca(OH)_(2)-PAC体系;CaCl_(2)-PAC体系中各因素对污染物去除效果的影响顺序为pH>CaCl_(2)投加量>PAC投加量;在15 g·L^(-1)CaCl_(2)、20 g·L^(-1)PAC以及初始pH=4.0的最优工艺条件下,对总磷、硫酸盐及COD的去除率分别高达98.9%、88.2%和60.2%;Ca^(2+)与PO43-生成Ca_(3)(PO_(4))_(2)和Ca_(10)(PO_(4))_(6)(OH)_(2)沉淀,同时,PAC水解产物Ala和Ca^(2+)及SO42-形成单硫型硫酸铝钙(AFm)沉淀,实现对总磷和硫酸盐的高效同步去除,并通过吸附-混凝-共沉淀的综合作用大幅削减有机污染负荷;二元酸废水中有机污染物以小分子酸为主,预处理后生物降解性略有下降,但仍属于易生物降解的有机废水;沉淀副产物具有再利用于混凝土膨化剂以及植物缓释磷肥的潜力。钙矾石沉淀法预处理工艺简单、效果稳定、成本低,该工艺可为投产二元酸装置石化企业污水处理系统的稳定达标运行提供有效保障。To avoid the impact of high concentrations of total phosphorus(TP)and sulfate in dicarboxylic acid wastewater on the wastewater treatment plant(WWTP)of petrochemical enterprises,an ettringite precipitation method was used to remove high concentration of TP and sulfate simultaneously,the orthogonal experiments with three factors and three levels were designed,the effects of calcium salt dosage,aluminum salt dosage and pH on pollutant removal were investigated,and the process parameters were optimized;the changes in organic pollution components of wastewater before and after pretreatment were studied by using GC-MS;the material composition of precipitation byproducts was analyzed by using XRD and XRF,and the potential for reuse of precipitation byproducts was explored by using ion dissolution experiments.The results show that the removal effect of pollutants by CaCl_(2)-PAC system was better than that by Ca(OH)_(2)-PAC system.In the CaCl_(2)-PAC system,the influence order of each factor on the pollutant removal effect was pH>CaCl_(2)dosage>PAC dosage.Under the optimal process conditions of 15 g·L^(-1)CaCl_(2),20 g·L^(-1)PAC,and initial pH=4.0,the removal rates of TP,sulfate,and COD were as high as 98.9%,88.2%,and 60.2%,respectively.Ca_(3)(PO_(4))_(2)and Ca_(10)(PO_(4))_(6)(OH)_(2)precipitation occurred between Ca^(2+)and PO43−,at the same time,a single sulfur aluminum calcium sulfate(AFm)precipitate occurred among PAC hydrolysis product Ala forms,Ca^(2+)and SO42−,the simultaneous removal of TP and sulfate was achieved,and the organic pollution load was largely reduced through adsorption-coagulationcoprecipitation.The organic pollutants in dicarboxylic acid wastewater are mainly small molecule acids,and its biodegradability decreased slightly after pre-treatment,but it still belonged to easily biodegradable organic wastewater.The byproducts have a potential for being reused as concrete expansion agents and plant slowrelease phosphate fertilizers.The pretreatment process is simple,stable and low in cost,which c

关 键 词：二元酸废水 化学沉淀 钙矾石法 预处理 正交实验设计 

分 类 号：X78[环境科学与工程—环境工程]