曝气方式对好氧颗粒污泥处理城市低C/N废水的探究

Study on the Treatment of Urban Low C/N Wastewater with Aerobic Granular Sludge by Aeration Mode

针对城市低C/N废水脱氮除磷效率低的现状,开发了基于不同曝气方式的好氧颗粒污泥(AGS)脱氮除磷新技术,研究了不同曝气方式对AGS去除污染的性能及污泥特征并探究相关作用机制。结果表明,相较于均匀曝气方式,逐步提高曝气强度利于AGS对污染物的去除,逐步提高曝气强度反应器中稳定出水化学需氧量(COD),溶解性磷酸盐(SOP)的去除效率分别高达91.7%~92.3%和90.5%,出水NH4+-N的质量浓度低至2.6~3.1 mg/L,上述去除效能显著高于均匀曝气及逐步降低曝气强度的反应器。机制分析表明逐渐提高曝气强度利于聚磷微生物对COD的吸收,SOP释放的浓度最高达40.3 mg/L,且出水NO3--N质量浓度低至6.3 mg/L,反硝化能力加强。此外,AGS污泥特征分析表明逐渐提高曝气提高污泥沉降性及污泥中生物量,且蛋白质与多糖的比值升高至1.42,高于其他曝气方式。

In view of the low efficiency of nitrogen and phosphorus removal of low-C/N wastewater in cities, a new technology of nitrogen and phosphorus removal by aerobic granular sludge(AGS) was developed based on different aeration methods. The performance of different aeration methods on AGS decontamination and the characteristics of sludge were studied, and the relevant mechanism was explored. The results showed that compared with the uniform aeration mode, the gradual increase of aeration intensity was beneficial to the removal of pollutants by AGS, and the removal efficiency of stable effluent COD, soluble phosphate(SOP) were 91.7%~92.3% and 90.5%, respectively. The concentration of NH4+-N in effluent was as low as 2.6~3.1 mg/L, which was significantly higher than that of uniform aeration and gradually reduced aeration intensity of the reactor. The mechanism analysis showed that the gradual increase of aeration intensity was conducive to the adsorption of COD by phosphorus accumulating microorganisms. The maximum concentration of SOP release was up to 40.3 mg/L, and the NO3--N in effluent was as low as 6.3 mg/L,so the denitrification capacity was enhanced. In addition, the characteristics of AGS sludge showed that the sludge sedimentation and biomass were improved gradually by increasing aeration, and the ratio of protein to polysaccharide increased to 1.42, which was higher than other aeration methods.