曝气与投加NaOH对养猪废水厌氧消化液磷回收的影响

Effects of aeration and adding NaOH on phosphorus recovery from anaerobically digested swine wastewater

以养猪废水厌氧消化液为对象,通过批次实验比较曝气与投加Na OH 2种方式调节废水p H值对磷回收效率的影响,并进一步采用流化床反应器探讨Na OH调节条件下进水流量对氮磷回收的影响。实验结果表明：采用曝气可促使p H值在1 h内迅速升高至8.6;随着曝气时间不断延长,p H值缓慢增长,至12 h达9.1～9.2,此时正磷酸盐（PO3-4-P）回收率达87.25%。投加Na OH调节最佳p H值为9.5,PO3-4-P回收率为85.67%。容积为100 L的搅拌-上向流反应器实验结果表明,当进水流量分别为50、100和150 L/h,在100 L/h流量条件下达到最优,PO3-4-P回收率为80.22%。利用X射线衍射仪（XRD）和扫描电镜及能谱仪（SEM-EDS）对沉淀产物进行表征,可知沉淀产物中含有磷酸铵镁（MAP）和Ca CO3。

This study compared the effects of aeration and the addition of sodium hydroxide（ Na OH） on phosphorus（ P） recovery from anaerobically digested swine wastewater. Experimental results showed that under the condition of aeration,p H value of solution rose rapidly to 8. 6 within 1 h,following slow increase,and then stayed relatively stable at 9. 1 to 9. 2 after 12 h. The orthophosphate（ PO3-4-P） recovery efficiency was87. 25%. In comparison,by adding Na OH,PO3-4-P recovery reached maximum at p H 9. 5,and the recovery efficiency was 85. 67%. In addition,a volume of 100 L stir upward flowing reactor with Na OH addition for PH adjustment was employed to investigate the effect of influent flow rate（ of 50,100 and 150 L / h） on PO3-4-P recovery. It was found that the optimal influent flow rate was 100 L / h,and 80. 22% PO3-4-P recovery was reached. The results of X-ray diffraction,and scanning electron microscope with energy dispersive spectroscopy（ SEM-EDS） showed that the recovered product was mainly composed of magnesium ammonium phosphate（ MAP） and Ca CO_3.