【作者】 姚樱；

【导师】 顾国维； 陈银广；

【作者基本信息】 同济大学 ， 环境工程， 2007， 硕士

【摘要】 聚糖菌(GAOs)是与聚磷菌(PAOs)共存于污水生物处理过程中的一类微生物。这类微生物在厌氧条件下吸收有机酸并合成聚羟基烷酸(PHA)，但不释放磷；在好氧条件下分解PHA，但不吸收磷，因而对污水中磷的去除没有贡献。近年来，随着人们对环境保护和可持续发展的日益重视，特别是生物可降解塑料具有化学合成塑料所没有的独特的可完全生物降解的性能，因此研究微生物方法合成生物可降解塑料成为国内外的一个研究热点。PHA是众多生物可降解塑料中的一种，由于生产成本较高限制了其使用，采用活性污泥中的GAOs合成PHA可有效降低PHA的生产成本。 本课题通过长期运行五个SBR装置在活性污泥中富集、驯化GAOs，着重研究了进水丙酸／乙酸和起始pH两个条件对富集GAOs的活性污泥系统的长期和短期影响。实验表明：(1)在进水丙酸／乙酸较低的条件下，富集GAOs的活性污泥系统中，PHA的厌氧合成量和好氧分解量、糖原的厌氧分解量和好氧合成量、一个周期内微生物的增殖量及系统中的脱氢酶活性等都较大；低丙酸／乙酸有利于GAOs的生长。(2)在丙酸和乙酸的碳摩尔浓度相同的情况下，GAOs吸收乙酸的速率较快，且在乙酸浓度适宜的情况下，GAOs对乙酸的吸收不需要长期驯化，短期提高进水中的丙酸量可抑制GAOs的生长。(3)厌氧起始pH值较高的条件下，富集GAOs的活性污泥系统中，PHA的厌氧合成量和好氧分解量、糖原的厌氧分解量和好氧合成量都较大；但一个周期内微生物的增殖量及系统中的脱氢酶活性等指标较小。高起始pH值不利于GAOs的生长但有利于PHA量的增多。 在获得GAOs在活性污泥系统中的富集后，重点研究了进水碳源、起始pH、进水氨氮浓度、工况等条件对于活性污泥中的PHA含量的影响。在低氨氮浓度、进水丙酸浓度490mg-COD／L、起始pH7.6的条件下，采用厌氧／好氧运行工况长期驯化下GAOs，在污泥干重中最大获得了58.9％的PHA含量。说明采用富集GAOs的活性污泥合成PHA的方法具有一定的可行性。更多还原

【Abstract】 Glycogen accumulating organisms (GAOs) were a kind of microbe which coexisted with phosphorus accumulating organisms (PAOs) in the biological Wastewater treatment process. Under anaerobic condition GAOs uptake volatile fatty acids (VFAs) to synthesize poly-β-hydroxyalkanoates (PHA) but do not release phosphate; and under aerobic condition GAOs degrade PHA but do not uptake phosphate, so GAOs do not contribute to the phosphate removal in the Wastewater treatment. Recently, as many people showed more concerns about environment protection and sustainable development, especially the unique complete biodegradablity of biodegradable plastic, the study on the biological synthesis of biodegradable plastic has become a hot topic. PHA is one kind of biodegradable plastic, but its high production cost limits the wide application of PHA. The method of employing the activated sludge enriched with GAOs to produce PHA could reduce the production cost effectively.Five bench-scale SBRs were operated to cultivate five kinds of activated sludge enriched with GAOs. The long-term and short-term effects of different propionic/acetic acid ratio and initial pH on the anaerobic and aerobic transformations of GAOs were studied. The biomass acclimated with lower propionic/acetic acid ratio Wastewater for a long term synthesized more PHA and degraded more glycogen in the anaerobic phase; and degraded more PHA and synthesized more glycogen in the following aerobic phase with a higher microbial dehydrogenase activity and a faster microbial growth rate. At the same time, for the biomass acclimated long term with the same concentrations of acetic acid and propionic acid, the acetic acid initial uptake rate would be faster than the propionic acid. The results also showed that GAOs could utilize acetic acid without acclimation and the short-term increase of propionic/acetic acid ratio can inhibit the proliferation of GAOs in EBPR system. The biomass acclimated long term with higher initial pH synthesized more PHA and degraded more glycogen in the anaerobic phase; and degraded more PHA and更多还原