浏阳河长沙段含藻水的自气浮混凝特性研究  

Characteristics of self-flotating coagulation for treating algae-laden water in Changsha section of Liuyang River

作　　者：万俊力[1,2] 张羽涵 聂小保[1,4] 张巍[1] 方鑫 孙士权[1,3] WAN Junli;ZHANG Yuhan;NIE Xiaobao;ZHANG Wei;FANG Xin;SUN Shiquan(School of Hydraulic and Environmental Engineering,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province,Changsha University of Science&Technology,Changsha 410114,China;Engineering and Technical Center of Hunan Provincial Environmental Protection for River-Lake Dredging Pollution Control,Changsha University of Science&Technology,Changsha 410114,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha University of Science&Technology,Changsha 410114,China)

机构地区：[1]长沙理工大学水利与环境工程学院,湖南长沙410114 [2]长沙理工大学洞庭湖水环境治理与生态修复湖南省重点实验室,湖南长沙410114 [3]长沙理工大学湖南省环境保护河湖疏浚污染控制工程技术中心,湖南长沙410114 [4]长沙理工大学水沙科学与水灾害防治湖南省重点实验室,湖南长沙410114

出　　处：《长沙理工大学学报（自然科学版）》2023年第4期55-63,共9页Journal of Changsha University of Science and Technology:Natural Science

基　　金：国家重点研发计划项目(2022YFE0105600);湖南省自然科学基金资助项目(2020JJ4613);郴州市国家可持续发展议程创新示范区专项资金资助项目(2021sfq15)。

摘　　要：【目的】改进蓝藻水华治理的化学混凝法,解决藻渣分离和收集等问题,优化化学混凝条件以提高目标污染物的去除率,同时降低二次污染风险。【方法】针对浏阳河长沙段含藻水的水质特征,提出具有自气浮作用的混凝处理新方法,即采用铝盐、亚铁盐、亲水性二氧化硅(SiO_(2))和碳酸钠进行含藻水的混凝处理,通过响应曲面二次回归模型确定除藻控磷的最佳混凝参数,结合混凝效果及藻絮体的表征分析探讨含藻水的混凝机理和自气浮特性。【结果】当n(CO_(2)^(3-))∶n(Fe+Al)(n为物质的量)和m(Si)∶m(Fe+Al)(m为质量)分别为1.75∶1和1∶2且投药量为0.525 mmol/L时,藻细胞和总磷去除效果以及藻絮体的自气浮效果最优,残余铝、铁的质量浓度降至水质标准限值以下。含藻水自气浮混凝处理的关键在于目标污染物与铝盐、亚铁盐水解产物及亲水性SiO_(2)之间的复杂相互作用:在混凝反应初期,压缩双电层和电性中和作用使藻细胞脱稳并凝聚;在混凝反应中后期,吸附架桥、网捕卷扫作用以及Si―C等官能团使目标污染物得以去除;总磷的高效去除源自磷酸铁和磷酸铝沉淀的生成,残余铝、铁的有效控制与亲水性SiO_(2)的吸附作用相关;Fe^(2+)与CO_(2)^(3-)发生双水解反应生成的CO_(2)气泡通过碰撞黏附在藻絮体上,从而使藻絮体自行上浮。【结论】用自气浮混凝方法处理含藻水,高效、稳定且安全,在洞庭湖水系藻类污染的应急处理或长效治理方面极具应用潜力。[Purposes]In order to improve the chemical coagulation method for treating cyanobacterial blooms and solve the problems of algal flocs separation and collection,chemical conditions of coagulation were optimized to increase removal efficiencies of target pollutants and reduce the risk of secondary pollution.[Methods]Based on the water quality characteristics of algae-laden water in Changsha section of Liuyang River,a new method of coagulation treatment with self-floation was proposed.Aluminium salts,ferrous salts,hydrophilic silicon dioxide and sodium carbonate were used to treat algae-laden water.The optimal coagulation parameters for algae and phosphorus removal were determined by the quadratic regression model of the response surface methodology.The coagulation mechanism and self-flotation characteristics were discussed by combining coagulation effect and characterization analysis of algal flocs.[Findings]When n(CO_(2)^(3-))∶n(Fe+Al)(n for the amount of matter)and m(Si)∶m(Fe+Al)(m for mass)were of 1.75∶1 and 1∶2 respectively,and the coagulant dosage was of 0.525 mmol/L,the highest removal efficiency of algal cells and total phosphorus,as well as the best degree of algae flocs self-flotating were achieved.Residual aluminum and iron concentrations were within the limit values of water quality standard.The self-floating coagulation treatment of algae-laden water was decided by the complex interactions between target pollutants and hydrolysis products of aluminum salt,ferrous salt,and hydrophilic silicon dioxide.In the early stage of coagulation,algal cells were destabilized and coagulated by compression of double electronic layer and electronic neutralization.In the middle and late stages of coagulation,target pollutants were removed by adsorption bridging,sweeping flocculation and functional groups of Si―C.The removal of total phosphorus and residual aluminum/iron depended on the formation of Fe_(3)(PO_(4))_(2)·H_(2)O and AlPO_(4).Effective control of residual aluminum/iron was related to the adsorptio

关 键 词：含藻水 铝盐 铁盐 自气浮 混凝机理 

分 类 号：X52[环境科学与工程—环境工程]