好氧颗粒污泥中丝状微生物生长研究

通过在序批式摇床反应器(SSBR)中分别接种絮状活性污泥与厌氧颗粒污泥来处理含盐及淡水2种废水并培养好氧颗粒污泥,研究好氧颗粒污泥中丝状微生物的过度生长及可行的控制措施.结果表明,进水水质与接种污泥类型都会影响颗粒污泥中丝状微生物的生长.同是接种好氧絮状污泥的R1、R3,由于R1进水为含盐废水而R3为淡水,R1中颗粒污泥丝状化程度低于R3,而接种厌氧颗粒污泥并处理含盐废水的R2颗粒污泥丝状化程度最低.当好氧颗粒污泥外部出现明显丝状微生物过度生长时,各反应器中颗粒污泥平均丝状化程度△分别达到△R1=1.4、△R2=1.2及△R3=2.0.对各反应器颗粒污泥中丝状微生物进行鉴定,R1颗粒中丝状微生物主要为Eikelboom 0092及Nocardia spp.,R2中主要为.Fungi spp.及Nocardia spp.,R3中主要为S.natans 及H.hydrossis,这几种类型丝状微生物一般出现在污泥龄长、溶解氧浓度低及基质易降解的环境中,但由于好氧颗粒污泥结构不同于传统活性污泥,试验通过控制污泥负荷、污泥龄及曝气量等并不能有效控制颗粒中丝状微生物的过度生长.试验将各反应器进水基质由易降解的葡萄糖配水换为难生物降解废水时,能快速有效地控制颗粒污泥中丝状微生物的过度生长.

Filamentous Overgrowth in Aerobic Granules

Filamentous overgrowth has been observed after aerobic granulation in shaking sequencing batch reactors (SSBR). The factors affecting the filamentous overgrowth in aerobic granules and its possible control methods were investigated. It was found that both the influent and sludge inoculation largely influenced the filamentous overgrowth in aerobic granules. With the same activated sludge inoculation, the filamentous overgrowth in R3 treating fresh wastewater was much more severe than that in R1 treating saline wastewater. The filamentous overgrowth in R2 was the least among the three reactors, which was inoculated anaerobic granules and treated saline wastewater. When the filamentous overgrowth happened at the outer aerobic granules, Delta referring the degree of filamentous overgrowth achieved DeltaR1 = 1.4, DeltaR2 = 1.2 and DeltaR3 = 2.0, respectively. Filamentous identification showed that the filamentous microorganisms in R1 mainly composed of Eikelboom 0092 and Nocardia spp., Fungi spp. and Nocardia spp. in R2, S. natans and H. hydrossis in R3. The identified filamentous microorganisms likely occurred in conditions with long SRT, low dissolved oxygen and biodegradable substrates. However, due to the fact that filamentous overgrowth in aerobic granules initiated in the inner part of the granules and acted as frameworks with rod-shape or coccoid bacteria entrapping into in the granulation period, various strategies effectively in dealing with conventional bulking problems including shorting SRT, changing organic loading rate and enhancing aeration et al, could not effectively inhibit the filamentous growth in aerobic granules. The filamentous overgrowth was ultimately controlled through changing the substrate from synthetic glucose-rich wastewater to non-biodegradable wastewater.