采用ASBR快速培养颗粒污泥及其菌群分析

Rapid Granulation of Sludge in Anaerobic Sequencing Batch Reactor:Strategy,Mechanism and Population Structure

厌氧序批式反应器(ASBR)因投资小、操作简单和运行灵活而倍受关注,但在ASBR中较难形成颗粒污泥,影响了该技术的推广应用。以葡萄糖为基质,探究在ASBR内快速培养颗粒污泥的方法,并对颗粒污泥的菌群结构进行了分析。结果表明,延长进水时间能够减少进水初期挥发酸(VFA)的积累,降低乙酸浓度,一个周期中乙酸的峰值浓度从93 mg/L下降到54 mg/L,促进了甲烷丝菌的增殖,有利于形成颗粒污泥;在进水中添加适量的Ca^(2+),大大促进了EPS的产生,其中蛋白质和多糖的含量均提高了3倍之多,这对加快污泥的颗粒化进程起到了重要作用。反应器运行80 d后以丝状菌为主的颗粒污泥形成,而后采用按梯度逐步提高进水COD负荷的方式继续培养,反应器运行150 d后以球状菌为主的颗粒污泥培养成熟,污泥粒径为0. 5～4. 0 mm,沉速为15. 0～38. 5 m/h。反应器中MLSS为7. 8 g/L,对COD的去除率达到97%～99%。

Anaerobic sequencing batch reactor （ASBR） has received much attention due to its low investment, simple operation and flexible control. However, the problems such as the difficulty to form granules limit its application. Therefore, rapid culture of anaerobic granular sludge was investigated in ASBR fed with glucose. To enhance the growth of granular sludge, ASBR was operated with long feeding time and Ca2. was dosed. The results showed that prolonging the feeding time and dosing Ca^2＋ could ac- celerate the formation of anaerobic granules in ASBR. Meanwhile, extension of feeding time could reduce the accumulation of VFA and decrease the concentration of acetic acid. The peak concentration of acetic acid decreased from 93 mg/L to 54 mg/L in a cycle, thus boosted the growth of Methanosaeta, which was in favor of the granulation of sludge. Adding some amount of Ca^2＋ could promote the bacteria cells to se- crete more PN and PS in EPS, in which the contents of PN and PS were nearly tripled, and obviously played an important role for the structure and maintenance of granules. After 80 days of operation granules with filamentous microorganisms were the dominant form of microbial aggregates in the reactor. Fur- ther the feeding time was decreased from 120 rain to 30 min and influent COD gradually increased with gradient, resulting in the formation of spherical bacteria matured in the granular sludge in 150 days with a diameter from 0.5 -4.0 mm and settling rate of 15.0 -38.5 m/h. The MLSS was 7.8 g/L in reactor, and the removal efficiency of COD reached 97% -99%.