【作者】 邢丽贞；

【导师】 张志杰；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2005， 博士

【摘要】 本文通过大量的藻类生长特性实验、藻类对氮磷去除实验及其结果分析,得出了适宜城市污水氮磷营养物质去除的优良藻种及相应的固定化方法。 研究发现,褐藻胶微观结构具有四通八达的网络通道,褐藻胶基质把细胞粘附在基质表面,这种网络结构十分有利于胶球内小球藻对氮磷营养物质的吸收。胶球内藻细胞密度越高,氮磷的去除率越高,胶球接种为高密度时,3d的NH₄⁺-N、PO₄^3--P的去除率分别达91.2%和100%。对固定化胶球进行加固处理后,可使胶球最大细胞密度比未加固处理提高近2倍,加固措施对克服褐藻胶在含磷污水中结构易疏松、小球藻易泄漏等问题是有效的,显著改善了固定化性能,进一步提高了氮磷的去除效率。鞘丝藻附着固定化的静态实验表明,鞘丝藻在氮磷比为10∶1、中等填料密度、生物量1.0g/L、饥饿2天的条件下对氮磷的去除效果最好。动态实验表明,鞘丝藻和颤藻附着固定化系统在水力停留时间为3d的情况下,NH₄⁺-N、PO₄^3--P的平均去除率分别达85.9%、68.5%。出水溶解氧含量高,水质大大改善。这些结果展示了固定化藻类在污水脱氮除磷方面的潜在应用前景。 固定化小球藻对氮磷的去除包括了褐藻胶的初期吸附、氮磷营养的传质、藻细胞对氮磷的吸收同化以及由于pH值升高引起的氨的气提和磷酸盐的沉淀。固定化小球藻对不同氮源吸收能力不同,其吸收的顺序为:氨氮>简单有机氮>硝态氮和亚硝态氮。在同等条件下,小球藻对不同磷的去除顺序则为:正磷酸盐>>偏磷酸盐>聚磷酸盐>>有机磷酸盐。 藻类包埋固定化与附着固定化相比较,包埋固定化去除氮磷的效率更高,藻类更易收获。附着固定化则更具有工程可操作性。 本文还对固定化藻类脱氮除磷机理进行了初步探讨,为固定化藻类去除污水中的氮磷物质提供了理论依据。更多还原

【Abstract】 Via a series of experiments on algae growth characteristics and removal of nitrogen and phosphorus, together with analysis of the experimental results, proper algae species and reasonable methods of immobilization is presented in this dissertation.During the investigations, the author found that the micro-structure in the carrier of consists of complex network channels. The algae cells are attached to the surface of algin. This kind of network structure is very helpful for the absorption of nutrition with nitrogen and phosphorus by the algae cells. The removal efficiency of nitrogen and phosphorus in wastewater was directly proportional to the holding capacity of algae cells in alginate balls. With high inoculating density of the immobilized Chlorella, the experiments got removal efficiency of 91.2% and 100% for NH₄⁺-N and PO₄^3--P respectively, in 3 days. After reharding, the maximum holding capacity was almost doubled than that of the system without reharding. The method of immobilization with reharding is effective to solve the problem that the balls loose their integrity and the algaes cells leach easily in the wastewater with phosphate. Therefore, the characteristics of immobilized balls and the removal efficiency for NH₄⁺-N and PO₄^3--P were greatly improved with reharding system. The static experiment of Lyngbya limnetica. attached system showed that the best removal efficiency of NH₄⁺-N、PO₄^3--P was achieved by conditions of 10:1 proportion of N/P, middling density of attaching material, 2 days hungry and biomass at 1.0g/L. According to the dynamic experiments, Lyngbya limnetica and Oscillatoria amoena Gom attached system got 85.9%、 68.5% removal efficiency for NH₄⁺-N and PO₄^3--P respectively in HRT 3 days. The dissolved oxygen in the effluent was increased obviously, and the water quality was greatly improved. All these show that immobilized algae have the potential application feasibility for the removal of nitrogen and phosphorus.The major manners of removal for nitrogen and phosphorus include: adsorption by algin balls at the starting phase; transmission of nitrogen and phosphorus; assimilation by Chlorella cells; gas stripping of NH₃ and phosphate precipitation caused by rising in pH. Immobilized Chlorella has unequal capability to assimilate various nitrogen resources. The sequence of absorption priority of different nitrogen by algae is NH₄⁺-N , urea, NO₃^- -N and NO₂^- -N. Within the same condition, the experiments of different phosphorus uptake by immobilized Chlorella showed that the order ofdifferent phosphorus uptake by Chlorella is ortho-phosphate, metaphosphate, polyphosphate, organic phosphate.Compared with attached algae system, embedded algae system has higher nutrient removal efficiency, and ingathering of algae is easier. However, attached algae system is easier to operation in engineering practice than the embedded one.Preliminary mechanism research on removal of nitrogen and phosphorus by immobilized algae is also presented in the dissertation.更多还原