不同孔径膜格栅对城市污水中污染物的截留效能及截留物发酵性能分析

Analysis of Interception Efficiency of Different Pore Size Membrane Grids for Pollutants in Municipal Wastewater and the Fermentation Performance of Residues

文章研究不同孔径膜格栅对城市生活污水中污染物的截留效能,并利用厌氧发酵产酸技术来分析阐明膜格栅截留物的发酵产酸性能。首先,采用筛网孔径为0.5、0.7、1.0 mm的标准筛模拟不同孔径的网孔板式膜格栅对城市生活污水进行一级处理。结果表明,3种孔径的标准筛对总化学需氧量(TCOD_(Cr)),特别是颗粒态化学需氧量(颗粒态COD_(Cr))有较好的截留效果,但对溶解性化学需氧量(SCOD_(Cr))的截留效果并不明显。与此同时,3种孔径的标准筛对总氮和总磷的截留效果均要优于对氨氮和正磷酸盐,对固体悬浮物(SS)的去除率均在30%以上,其中0.5 mm孔径的标准筛的去除率最高,达到了43.31%,1.0 mm孔径的标准筛的去除率相对较低,但也达到了34.74%。随后,考察了在中温(35℃)、pH值=10的条件下,利用膜格栅截留物(栅渣)进行厌氧发酵产生挥发性脂肪酸(VFAs)。结果表明,在厌氧发酵周期内,发酵液中SCOD_(Cr)的浓度随着发酵时间的延长不断升高;而发酵液中VFAs的含量呈现出先增长后下降的趋势,并于第8 d达到最大值。可见,利用截留物水解发酵可以为生物脱氮工艺提供优质的碳源。

The interception efficiency of different pore size membrane grids for pollutants in municipal wastewater was introduced in this paper.In addition,the fermentation performance of membrane grid residues was analyzed using anaerobic fermentation technology.The standard sieves with diameters of 0.5,0.7,1.0 mm were used to simulate different pore size membrane grids for primary treatment of municipal wastewater.Three kinds of standard sieves had good interception effect on total chemical oxygen demand(TCOD_(Cr)),especially granular chemical oxygen demand,however the interception effect on soluble chemical oxygen demand(SCOD_(Cr))was not obvious.In the meantime,the interception effect of total nitrogen and total phosphorus was better than that of ammonia nitrogen and phosphate.The suspended solids(SS)removal rate was above 30%,the standard sieve with 0.5 mm pore size had the highest removal rate,reaching 43.31%.The standard sieve with 1.0 mm pore size had a relatively low removal rate,but also reaching 34.74%.Subsequently,the production of volatile fatty acids(VFAs)by anaerobic fermentation using membrane grid residues was investigated,operated at medium temperature(35℃)and pH value=10.The results showed that during the anaerobic fermentation period,the concentration of SCOD_(Cr)in the fermentation broth increased with the prolongation of fermentation time.While the content of VFAs in fermentation broth increased first and then decreased,and reached the maximum on the eighth day.It can be seen that the hydrolysis and fermentation of residues can provide high quality carbon source for biological nitrogen removal process.