Transformation and performance of granular sequence batch reactor under conventional organic loading rate condition

Laboratory experiments were conducted to investigate the transformation and performance of a granular sequence batch reactor（SBR） under the conventional organic loading rate（OLR） condition.Aerobic granules were successfully cultivated in a SBR by means of alternative feeding load combined with reducing settling time after 60 d operational period.Subsequently,the black fungal granules were presented in reactor because of the filamentous overgrowth on the surface of aerobic granules.A small amount of fungal granules had no effect on the performance of granular SBR.Aerobic granules completely vanished and fungal granules eventually became the dominant species in subsequent 90 d operation after granulation.The three-dimensional excitation emission matrix（EEM） spectra result shows that the extracellular polymeric substances（EPS） component in both granules has no much difference,whereas the content of EPS in fungal granules is higher than that in bacterial granules.Due to their low bioactivity,the chemical oxidation demand（COD） and NH4-N removal efficiencies gradually decrease from 90.4%–96.5% and 99.5% to 71.8% and 32.9% respectively while the fungal granules become dominant in the SBR.     

Characteristics of extracellular fluorescent substances of aerobic granular sludge in pilot-scale sequencing batch reactor

The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor (SBR), and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances (EPS) of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix (EEM) fluorescence spectra of the EPS in the aerobic granules. Two peaks (A and B) are attributed to the protein-like fluorophores, and the third (peak C) is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid (peak D) is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvic-like substances are also associated with the disintegration of the aerobic granules.     

生物传感器快速测定BOD仪的开发

对生物传感器快速测定BOD的试验装置与测定方式进行了改进,改进后的测定系统具有良好的重现性和准确度。同时确定了最佳测定条件为温度30℃,PH5．0,固定化细胞15g。     

生物传感器快速测定BOD的研究

介绍了一种以一株耐高渗透压的酵母菌种作为敏感材料制成的生物传感器、采用稳态吸速率法进行生化需氧量（BOD）的快速测定的方法。该方法与广为采用的5d生化需氧量标准稀释测定法有良好的相关性,线性范围为0－200mg／L,可在15min内完成一个样品BOD的测定,测量恢复时间为30min。敏感材料的生物活性与测定样品中有机物的种类有密切关系。固定化酵母具有较好的稳定性,可连续使用一个月以上。