School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China E-mail:
Aalborg University, Department of Energy Technology, Pontoppidanstraede 111, DK-9220 Aalborg, Denmark.
Water Sci Technol. 2021 May;83(10):2560-2574. doi: 10.2166/wst.2021.132.
This study aimed to enhance the removal of phosphate in synthetic rural sewage by using a continuous electrocoagulation (EC) combined with biofilm process in an integrated system. Characteristic indexes of biofilm process effluent covering pH, dissolved oxygen (DO), suspended solids (SS), chemical oxygen demand (COD) and phosphate maintained a narrow fluctuation range and tended not readily to influence the phosphate removal of subsequent electrocoagulation. Three parameters including inter-electrode distance, current intensity and reaction time were selected to investigate the performance of enhancing phosphate removal. On the strength of single-factor tests, the Box-Behnken design (BBD) coupled with response surface methodology (RSM) was applied to investigate the individual and mutual interaction impacts of the major operating parameters and to optimize conditions. The optimum conditions were found to be inter-electrode distance of 1.8 cm, current density of 2.1 mA/cm and EC reaction time of 34 min, and phosphate removal efficiency of 90.24% was achieved along with less than 1 mg/L in case of periodic polarity switching mode, which raised removal efficiency by 10.10% and reduced operating cost by 0.13 CNY/g PO compared to non-switching mode. The combination of biofilm processing and electrocoagulation treatment was proven to be a valid and feasible method for enhancing phosphate removal.
本研究旨在通过在集成系统中使用连续电絮凝（EC）结合生物膜工艺来提高合成农村污水中磷酸盐的去除率。生物膜工艺出水的特征指标包括 pH 值、溶解氧（DO）、悬浮固体（SS）、化学需氧量（COD）和磷酸盐都保持在较窄的波动范围内，不易影响后续电絮凝的磷酸盐去除效果。选择三个参数，包括电极间距、电流强度和反应时间，来考察增强磷酸盐去除的性能。在单因素试验的基础上，采用 Box-Behnken 设计（BBD）结合响应面法（RSM）来考察主要操作参数的单独和相互作用影响，并优化条件。发现最佳条件为电极间距 1.8cm、电流密度 2.1mA/cm 和 EC 反应时间 34min，在周期性极性切换模式下，磷酸盐去除率达到 90.24%，而周期性极性切换模式下的磷酸盐浓度低于 1mg/L，与非切换模式相比，去除效率提高了 10.10%，运行成本降低了 0.13 CNY/g PO。生物膜处理与电絮凝处理相结合被证明是一种有效且可行的增强磷酸盐去除的方法。
