Phospholipid fatty acids analysis of the vertical distribution of microbial communities in eutrophic lake sediments

Vertical distribution of microbial communities in a eutrophic lake sediments of Lake Xuanwu was quantified by phospholipid fatty acids analysis and multivariate statistical analysis was employed to interprete the data. Principle component analysis of sediment characteristics parameters, including total nitrogen, total phosphorus, organic matters and pH produced clustering of sampling sites for two distinct groups. These groups corresponded with the two sampling stations and the levels of nutrient enrichment. Total phospholipid fatty acids concentration, which is indicative of microbial biomass, reduced with depth, however, the relative percentage of anaerobic prokaryotes increased. To assess changes of microbial community along depth, phospholipid fatty acids compositions were analyzed by cluster analysis. Distinct clusters were observed in different sampling stations. Canonical correspondence analysis was carried out to infer the relationship between sediment characteristics and microbial communities. Phospholipid fatty acids samples collected at the same sampling site clustered together. Canonical correspondence analysis revealed that the environmental parameter with the greatest bearing on the phospholipid fatty acids profiles was pH. This study proved the successful application of phospholipid fatty acids and multivariate analysis to investigate the relationship between environment factors and microbial community composition

Environmental biological model based on optimization of activated sludge process

A simplified environmental biological model has been developed based on biodegradation kinetics correlation to regulate and optimize wastewater treatment system of activated sludge process. All parameters included in the model are calibrated in accordance with reference data and experimental results and good agreements are achieved between calculated results and reference data or experimental results. The minimum bioreactor volume is used as objective function in the model and errors between optimal minimum volume of the model and each reported result of three references are found to be no more than 8.63% after validation. Comparisons between optimal results and experimental data demonstrate that the deviations are negligible. The optimal minimum volume is 9.21 m3 with the error of 6.40% to the practical bioreactor volume of a pilot treatment system. The environmental biological model has been applied to economically evaluate a former treatment system with native bacterium YZ1 and four operation periods of the pilot system with functional strain Fhhh compared with YZ1, Fhhh possesses higher biodegradation ability in purified terephthalic acid wastewater and a broader economic potential in the field of wastewater treatment