碳泥回流对于超滤组合工艺的影响

Influence of carbon mud reflow on operation of UF combine process

南郊水厂二期采用"气动絮凝—短程沉淀(碳泥回流)—超滤—二氧化氯消毒"短流程超滤组合工艺,该组合工艺用超滤膜池取代滤池,将沉淀池长度缩短2/3,减少了水厂建设成本,同时通过回流高浓度含炭污泥节省了活性炭投加量,降低了水厂的运行成本。二期短流程组合工艺通过碳泥回流提高了整体的净水效能,可以稳定高效地去除浊度、微生物和藻类,对COD_(Mn)、氨氮、UV_(254)的平均去除率分别为39.48%,51.23%和48.6%,出水水质满足《生活饮用水卫生标准》(GB5749—2006)的要求。但是在水量较大时,短程沉淀池的沉淀效果不理想,超滤膜池进水浊度较大,导致超滤膜跨膜压差上升较快,物理清洗以及维护性清洗频繁。因此,有必要进一步提高短流程沉淀池的沉淀效果,控制超滤膜的进水浊度。

Combination process with ＂aerodynamic flocculation-short bed sedimentation （carbon mud reflow）-ultrafiltration-chlorine dioxide disinfection＂ was adopted in the second phase of the Nanjiao waterworks. The combination process replaced the filter and shortened the length of the advection pool, which had less structure and less management point. At the same time, active carbon could be fully utilized by the high concentration of carbon sludge reflux, and it greatly reduced the consumption of powdered activated carbon, the construction and operating costs. The average removal rates of CODMn, ammonia-nitrogen and UV254 were 39.48 % , 51.23% , 48.6%. The water quality fully fit the Standards for Drinking Water Quality（GB5749-2006） requirements. However, when the amount of water was large, the effect of the short-range sedimentation tank was not ideal. The turbidity of the uhrafiltration membrane was larger, which led to the rapid increase of the membrane pressure difference, and the physical cleaning and maintenance cleaning were more frequent. Therefore, it was necessary to further improve theshort-process sedimentation tank effect and to control the ultrafiltration membrane water turbidity.