利用季铵盐有机改性铝污泥絮凝除藻试验

选择具有良好吸附沉降性能的给水厂副产物铝污泥作为下沉载体替代粘土,探究季铵盐十六烷基三甲基溴化铵(CTAB)对铝污泥的吸附改性,并将其用于常见淡水小球藻(Chlorella)的絮凝去除试验。结果显示:(1)经600℃焙烧后的铝污泥对浓度为36.4 mg/L的CTAB改性溶液吸附能力最强,10 min内即可达到吸附平衡,吸附容量为9.19 mg/g;(2)当改性铝污泥中原始用量为3.0 g/L时,24 h后对藻密度和浊度的去除率可分别达到80.25%和80.05%;(3)改性剂CTAB不会影响铝污泥对磷酸盐的吸附性能,改性前后的铝污泥对磷的最大吸附率分别为90.91%和90.77%,且都在2 h左右达到吸附平衡。研究表明,有机改性铝污泥可初步形成一个除藻抑藻体系,可为藻类的去除和铝污泥的资源化利用提供理论依据及技术支持。

Flocculation and Removal of Algae by Alum Sludge Modified with an Organic Quaternary Ammonium Salt

Excessive growth of algae in eutrophic freshwater threatens aquatic ecosystems and the health of local residents. Among algae removal methods, clay flocculation is the most promising technique and has attracted considerable attention. However, large quantities of clay are required for large scale algae removal and clay resources are finite. Research has shown that alum sludge, a by-product of conventional water treatment, has good adsorption and sedimentation performance and can be used rather than clay. In this study, hexadecyltrimethylamine bromide(CTAB), an organic quaternary ammonium salt, was used to modify alum sludge for the first time and the removal efficiency of Chlorella was tested. Results show that:(1) Alum sludge calcined at 600℃ has the best adsorption capacity for CTAB(36.4 mg/L), and adsorption equilibrium was achieved within 10 min(9.19 mg/g);(2) After 24 h, at a dose level of 3.0 g/L, modified alum decreased the algal density and turbidity, respectively, by 80.25% and 80.05%;(3) CTAB had little effect on phosphorus adsorption by alum sludge. Phosphorus removal reached 90.91% and 90.77%, respectively, by raw alum sludge and modified alum sludge, and equilibrium was achieved after 2 h in both cases. To summarize, this research demonstrates that a waste product, alum sludge, can be modified and used to remove algae and control phosphorus from eutrophic waters.