盐度对污水生物处理系统藻酸盐分泌的影响及作用机制研究

Alginate is a kind of polysaccharide polymer extracted from seaweed and extracellular bacteria, which is an important industrial raw material. In recent years it has been found that alginate extraction can be achieved from the sludge of the wastewater biological treatment system. To deal with the issue of fresh water scarcity in China's coastal areas, the domestic seawater technology is being applied in these areas. However, the effect of salinity from the seawater on the content and properties of alginates in activated sludge is still unclear..In this research, the effects of salinity and salt type on the content and properties of alginate extracted from the activated sludge treatment system will be studied, combined with the distribution of alginate in bacterial extracellular polymer. At the same time, salinity will be introduced to establish a mathematical model simulating the alginate synthesis kinetics. Based on on the changes of the intermediate metabolites Fru6P and GTP, c-di-GMP and microbial populations during the short-term and long term salinity conditions, the mechanism of the alginate secretion in salinity conditions will be explored from the perspectives of the stress response of microbial metabolism and the metabolism of different populations. The results will provide a theoretical basis and technical support for the extraction of alginates from the domestic seawater treatment system.

藻酸盐是从海藻体内和细菌胞外提取的一种多糖类聚合物，是一种重要的工业原料。近年来已发现可以从污水生物处理系统的污泥中实现藻酸盐的提取。随着我国沿海地区淡水资源紧缺问题的出现，大生活用海水技术开始推广应用。由于大生活用海水中盐度较高，而盐度对活性污泥中藻酸盐的含量和特性的影响还不清楚。.本项目针对盐度和盐类型对活性污泥处理系统中藻酸盐的含量和特性的影响作用进行研究，建立盐度作用下的藻酸盐分泌的数学模型。并根据盐度的短期冲击和长期运行下藻酸盐合成中的中间代谢产物Fru6P和GTP、c-di-GMP和微生物种群的变化情况，从微生物代谢和种群变化的角度解析微生物应对盐度冲击的应激反应和长期的种群变化对藻酸盐分泌的影响机制。研究结果为大生活用海水污水处理系统污泥中提取藻酸盐提供理论依据和技术支持。

藻酸盐是一种应用广泛的医药、食品、工业原材料，除从褐藻和纯培养微生物中获取藻酸盐外，从污水生物处理系统中提取细菌藻酸盐，也是获取藻酸盐并实现污泥减量化和资源化利用的新方向之一。研究以沿海城市推广使用大生活用海水技术为背景，从含盐城市生活污水处理系统中提取藻酸盐为目标，考察了不同海水比例所产生的盐度对污水生物处理系统中藻酸盐分泌的影响。研究发现不同海水比例会影响系统中藻酸盐的分泌：海水比例从0%增加到100%，污泥藻酸盐的提取量从74.02 mg/g-VSS增加到114.41 mg/g-VSS。由红外光谱分析可知，六种盐度下藻酸盐的性质相近。从不同区段分离和乙酰化含量的得出，盐度越高其甘露糖醛酸（M）比例越大，乙酰化程度也越高，藻酸盐的持水性和溶胀性能更好。其中80%海水比例的活性污泥处理系统可保持较高的污染物去除效果同时可从剩余污泥中获得较高的藻酸盐含量。盐度对污水生物处理系统的微生物种群结构的影响及对第二信使环二鸟苷酸分泌的影响是造成藻酸盐含量不同的重要原因。