给水厂残泥作为晶种对MAP法预处理垃圾渗滤液的影响研究

Study on the Effect of Drinking Water Treatment Residuals as Seed Crystal on MAP Pretreatment of Landfill Leachate

磷酸镁铵法(MAP)去除废水中的氨氮速度快且效果明显,但一般结晶后的晶体颗粒小,不易沉降.加入晶种后,以晶种为晶核,促进晶体粒径的增大,从而提高结晶产物整体的沉降性能及对氨氮的去除率.该研究以给水厂残泥(WTR)为晶种,探究不同工艺条件包括晶种投加量、溶液pH和反应镁磷比对MAP法预处理垃圾渗滤液中高浓度氨氮的效果影响.结果表明:在WTR投加量为10 g/L,pH=9,镁磷比为1.3∶1的最佳条件下,氨氮的去除率可达到89.55%,比未投加晶种时的去除率提高了23.74%,效果明显.SEM表明,在此条件下,磷酸镁铵的结晶体通过结合WTR晶种,晶体粒径增大,有利于其固液分离.

Magnesium ammonium phosphate method(MAP)removes ammonia nitrogen from wastewater quickly and effectively,but generally the crystal particles after crystallization are difficult to settle.After adding seeds,the seed crystal is used as nucleus to promote the increase of crystal size.The sedimentation performance of the whole crystal product and the removal rate of ammonia nitrogen are improved.In this study,drinking water treatment residuals(WTR)of water supply plant was used as seed to study the effects of different technological conditions,including seed dosage,solution pH and reaction magnesium to phosphorus ratio on the high concentration of ammonia nitrogen in the landfill leachate by MAP.The results showed that under the optimal conditions of WTR dosage of 10 g/L,pH=9 and the ration of Mg and P is 1.3∶1,the removal rate of ammonia nitrogen can reach 89.55%,which is 23.74%higher than that without crystal seeds.SEM showed that under these conditions,the crystal of ammonium magnesium phosphate was combined with WTR seed crystals,and the crystal grain size was significantly increased,which was favorable for solid-liquid separation.