MAP晶体捕集反应器回收猪场厌氧消化液中磷的研究

Phosphorus recovery from anaerobic-digested piggery wastewater by collecting reactor of map crystal

研究了磷酸铵镁(MAP)结晶法晶体捕集反应器在曝气条件下回收猪场厌氧消化液中磷元素的能力.结果表明,利用曝气方式提高猪场厌氧消化液的p H值,进行MAP结晶回收磷完全可行.MAP的饱和度指数(SI)与废水p H值呈多项式函数关系,结晶反应的最佳p H值为8.5~9.0;随着曝气时间延长至180 min,反应器内废水p H值可提高至8.5;常温下(25℃),反应器内MAP回收磷的反应动力学的反应级数(n)为1.98,速率常数(K25)为7.04×10-4L·mg-1·min-1;反应器单个运行周期为270 min;磷的平均去除率为82%左右.MAP晶体捕集反应器上的晶体在一个反应周期内即可成形,随着反应周期的增加,晶体颗粒逐渐增大.利用扫描电镜和X射线衍射仪对捕集器所捕集的晶体进行了表征,证实晶体为高纯度的MAP.

Study was conducted on the phosphorus( P) recovery of magnesium ammonium phosphate( MAP) crystal collecting reactor from anaerobicdigested piggery wastewater under aeration condition through MAP crystallization. The results showed that it was feasible to recover P through MAP crystallization when p H value of anaerobic-digested piggery wastewater was raised by aeration. The saturation index( SI) of MAP was the polynomial function of piggery wastewater p H value,with the optimal p H value of 8.5 ~ 9.0 for crystallization. The piggery wastewater p H value would raise to 8.5,when the aeration period was prolonged to be 180 min. Under room temperature( 25 ℃),the reaction kinetics order( n) of P recovery by MAP in the reactor was 1.98,with the rate constant( K25) of 7.04×10-4L·mg-1·min-1. With the single operating cycle of 270 min,the average P removal efficiency was around 82%. The MAP crystal could be formed on the collecting reactor within one cycle and would gradually grow as the reaction cycle increased. The component and structural analysis by scanning electron microscopy and X-ray diffraction indicated that the crystal was high pure MAP crystalline.