A/O工艺结合化学沉淀法处理城市河道水的研究

Treatment of Severely Polluted Urban River Water by Combined Process of A/O and Chemical Precipitation

试验采用强化脱氮的A/O工艺对具有我国南部城市河道水典型特征的深圳布吉河道水进行处理,通过添加外碳源(甲醇)提高TN去除效果,并向二沉池出水添加PAC(聚合氯化铝)进行混凝沉淀以降低TP和SS。试验结果表明,单独采用A/O工艺处理河道水,二沉池的出水COD达到《污水综合排放标准》(GB8978-1996)一级标准,TN达到二级标准,TP和SS不达标。通过向缺氧段添加甲醇调节C/N可有效降低出水TN,比较C/N分别为2、4、6时的水处理效果,当C/N=4时的二沉池出水TN即可达到一级标准,且C/N=4时的性价比最佳。二沉池出水如再经PAC化学沉淀后,TP、SS均可达到一级标准,TN和COD也较化学沉淀前有所下降。通过添加外碳源强化脱氮的A/O工艺结合化学沉淀法是一种高效、易于维护和管理的河道水异地处理方法。

A/O process with chemical precipitation and the dosage of methyl alcohol were used for treatment of severely polluted urban river water in Buji,Shenzhen.Results indicated that by only A/O process,the effluent COD could meet Grade I of discharge standard of GB8978-1996,and the effluent TN could meet Grade II.However,the removal of TP and SS was poor.Dosage of methyl was added for better denitrification,and the effluent TN could meet Grade I standard when C/N was adjusted to 4.Results also indicated that removal of TN with C/N adjusted to 4 had a better performance/price ratio compared to those when C/N was adjusted to 2,4 or 6.After chemical precipitation,TP and SS both could meet Grade I with small decrease of both COD and TN.The combined process could be applied easily to treatment of severely polluted urban river water with high efficiency in separate regions.