磁絮凝-吸附技术对黑臭水体中浊度、氨氮和总磷的去除效果及机理

Performance and mechanism of turbidity,ammonia nitrogen and total phosphorus removal from black and odorous water by magnetic flocculation-adsorption technology

采用磁絮凝-吸附技术开展了同步去除黑臭水体浊度、氨氮和总磷(TP)实验。在磁絮凝阶段,通过聚合硫酸铁(PFS)、磁粉(MPs)和聚丙烯酰胺(PAM)复配使用,利用电荷中和作用去除浊度和TP;同时,利用化学吸附沉淀去除TP;在此阶段中,当PFS、MPs、PAM的投加量分别为16.00、100.00、2.20 mg·L^(-1)且以PFS+MPs在快速阶段先投加,PAM在慢速阶段后投加的顺序投配时,絮凝效果达到最佳。在吸附阶段,吸附剂质化壳聚糖-沸石(PCZ)主要通过离子交换作用去除氨氮以及通过静电吸附作用去除TP;当PCZ的投加量为1.25 g·L^(-1)时吸附效果达到最佳。利用所研究的磁絮凝-吸附技术对实际黑臭水体进行处理,其出水浊度能达到城镇污水处理厂污染物排放一级标准(≤10.00 NTU),TP和氨氮也分别能满足地表水环境质量Ⅲ类标准(≤0.20 mg·L^(-1))和Ⅴ类标准(≤2.00 mg·L^(-1))要求。

In this paper,a magnetic flocculation-adsorption technology was studied for simultaneous removal of turbidity,ammonia nitrogen and total phosphorus(TP)in black and odorous water.At the magnetic flocculation stage,polyferric sulfate(PFS),magnetic powder(MPs)and polyacrylamide(PAM)were jointly used to remove turbidity and TP through charge neutralization,especially to remove TP through chemical adsorption precipitation.In the process of magnetic flocculating,the optimal dosages of PFS,MPs and PAM were 16.00,100.00 and 2.20 mg·L^(-1),respectively.Both PFS and MPs were added first at the rapid mixing stage,then PAM was added later at the slow mixing stage,the best flocculation effect occurred.At the adsorption stage,protonated chitosan combined with zeolite(PCZ)was used to remove ammonia nitrogen and TP by ion exchange and electrostatic adsorption.At PCZ dosage of 1.25 g·L^(-1),the best adsorption performance occurred.When this magnetic flocculation-adsorption technology was used to treat the actual black and odorous water,the turbidity of the treated wastewater could meet the class I standard of pollutant discharge of urban sewage treatment plant(≤10.00 NTU),and TP and ammonia nitrogen could also meet the class III standard(≤0.20 mg·L^(-1))and class V standard(≤2.00 mg·L^(-1))of surface water environmental quality,respectively.