添加晶种对沼气发酵液磷回收的影响研究

以畜禽养殖废水经厌氧消化处理后的沼气发酵液为研究对象,采用曝气吹脱调节pH的处理方式。晶种采用海泡石粉、沸石粉和凹凸棒石粉3种天然矿物材料。考察了不同pH条件、晶种添加量和不同初始磷负荷对磷回收的影响,并利用扫描电镜-能谱分析仪(SEM-EDX)对产物进行了表征分析。结果表明:3种晶种材料中,凹凸棒石粉对磷回收的促进效果最好。在pH从7.5到8.5之间海泡石粉、沸石粉和凹凸棒石粉均可将Rp(t)提高10%以上,8.5到9.5之间,添加海泡石粉和沸石粉对Rp(t)的提升幅度降低,添加凹凸棒石粉可以达到14%左右的提升幅度。海泡石粉和沸石粉添加量增大后Rp(t)有小幅的提升,但变化不规律,凹凸棒石粉的最佳添加量为0.92 g/L。初始PO43--P为90 mg/L时凹凸棒石粉对磷回收有最好的促进效果。添加凹凸棒石粉的产物在SEM图片上可看到明显有晶体覆盖,EDX图上出现了明显的强度较大的P组分峰,从微观的角度证实了添加凹凸棒石粉的促进作用。

Study on effect of crystalline seeds addition on phosphorus recovery from biogas fermentative liquid

Taking the biogas fermentative liquid treated by anaerobic digestion process from livestock wastewater as the research object,using the treatment method of aeration stripping and using sepiolite powder,zeolite powder,attapulgite powder as crystalline seeds,the effects of different pH value,addition amount of crystalline seeds,initial phosphorus loads were investigated and characterization of crystalline product was analyzed using scanning electron microscopy(SEM) and energy dispersive X-ray analysis(EDX).The results are as follows: The effect of attapulgite powder for phosphorus recovery is the best among the three kinds of seeds in this study.Rp(t) increased more than 10% with the addition of the three crystalline seeds when pH value ranged between 7.5 to 8.5.When pH value ranged between 8.5 to 9.5,Rp(t) increased 14% after adding attapulgite powder while after adding sepiolite powder and zeolite powder Rp(t) reduced.So with the addition of attapulgite powder Rp(t) increased most and the optimal addition amount was 0.92 g/L.And Rp(t) was the highest when initial phosphate load was 90 mg/L when adding attapulgite powder.Crystal could be seen apparently from the SEM picture at the surface of crystalline product after addition of attapulgite powder,and a strong P peak was appeared on the EDX picture.The promotion of phosphorus recovery when adding attapulgite powder is conformed from microcosmic point of view.