摘要
为了获取优化的污水除磷工艺,基于前期对白云石石灰结晶流化床去除厌氧消化上清液中磷的工艺条件和参数的初步探究,考察了不同酸化程度下白云石石灰释放Mg2+、Ca2+的效果,并根据MAP反应特点,选择出酸化液体积为5、6.5和10 m L,分别对应n(Mg)/n(P)为0.6、1.4、2.2进行后续实验。利用响应面法(RSM)对白云石石灰结晶流化床强化除磷工艺的影响因素进行分析和探讨,考察了p H值、n(Mg)/n(P)与停留时间(HRT)(分别记为X1、X2、X3)及各因素之间交互作用对磷去除率的影响,并利用扫描电子显微镜、X射线衍射和傅里叶变换红外光谱对产物进行表征,得出最佳工艺参数为p H=9.5、n(Mg)/n(P)=2.2、HRT=3.0 h。RSM法所建立的回归模型显著,实验精准度、精密度和可信度均在合理范围内,回归方程中X1、X2、X3、X1X2、X1X3、X21、X22、X23对磷去除率影响显著。产物MAP晶形较好,但由于废水的碱度较大(20 mmol/L),产物中含有大量的Ca CO3沉淀。
To obtain optimized process for phosphorus removal from wastewater,based on the early research on the process conditions and parameters of process of phosphorus removal from anaerobic digestion supernatant by dolomite fluidized bed crystallization,acidification experiments on dolomite were carried out in order to study the effects on the releasing capability of Mg2 +and Ca2 +.According to MAP reaction characters,the acid volumes added to the water were selected at 5 m L,6.5 m L,and 10.0 m L,respectively.These three values were corresponding to the n(Mg)/n(P) ratio of 0.6,1.4,and 2.2,respectively.Using response surface methodology to analyze the effects on intensification process,p H values,the ratio of n(Mg)/n(P),hydraulic retention time(HRT)(respectively coded as X1,X2,X3) were investigated as well as the interaction effect on phosphorus removal.The precipitates were characterized by using scanning electron microscope,X-ray diffractometer,Fourier transform infrared spectrometer,respectively.It was found that the optimum conditions were p H values at 9.5,the ratio of n(Mg)/n(P) at 2.2 and HRT at 3.0 h.The level of quadratic response surface model was significant,and the experimental accuracy,precision and reliability were all within reasonable limits.The model showed that X1,X2,X3,X1 X,X1X3,X21,X22,X23 had significant effects on phosphorus removal.The MAP was good crystal.But due to the high concentration of carbonate in the treated wastewater(20 mmol/L),Ca CO3 accounted for larger percentage of the precipitate.
出处
《环境工程学报》
CAS
CSCD
北大核心
2015年第2期586-594,共9页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(51078339)
中央级公益性科研院所基本科研业务专项(2011KYYW-01)
关键词
厌氧消化液
除磷
白云石石灰
流化床结晶反应器
响应曲面
anaerobically digested effluent
phosphorus removal
dolomite
fluidized bed crystallizer
response surface methodology
