Knowledge of Wastewater treatment: a mechanism for
Knowledge of Wastewater treatment: a mechanism for the formation of activated sludge bacterial micelles
In the past 30 years, Chinese industrialization and urbanization has brought serious water pollution problems. At present, the application of activated sludge of biochemical treatment is the mainstream technology of urban sewage treatment. It is resulting more than 3000 million tons of massive sludge annually which are failed to get proper disposal and effective use. And it is possible to cause secondary pollution. In addition, Sludge bulking is often used in the process of activated sludge process, which has a serious impact on the treatment efficiency. Activated sludge research and development is imminent.
Activated sludge formation is the premise of gravity separation and sludge reuse (maintaining the concentration of microorganisms in the aeration tank), which is the key to the success of activated sludge process. Research Institute of aquatic biology, Chinese Academy of Sciences, Dongru Qiu discipline group on the formation of activated sludge microbial strains of the mechanism for a more in-depth study.
They were separated from the urban sewage treatment plants in Wuhan and Hong Kong to obtain a series of research, and the following results were obtained:
1). Genome sequencing and annotation of 1 strains of bacteria were carried out to reveal the characteristics of carbon, nitrogen and phosphorus metabolism in the dominant bacteria of the activated sludge;
2. Through the molecular genetic analysis of the insertion mutagenesis, gene site knock out and genetic complementation test. So that a large gene cluster related to the formation of the MMB strain was identified;
3). It has been found that two encoding asparagine synthetase paralogs homologous gene in zoogloea forming process has an important function. The two gene mutation or knockout to block or delay the formation of zoogloea;
4). By comparative genomics analysis, it is shows that a similar gene cluster also exist in other important activity sludge bacteria genomic or metagenomic (especially phosphorus accumulating bacteria, the bacteria in enhanced biological phosphorus removal process plays an important role, but also failed to isolate and Culture) that these bacteria can also form zoogloea. Thereby, through a specific process in the activated sludge can play an effects;
5) After the preliminary analyse the extracellular polysaccharide of monosaccharide composition, it is found that the gene cluster of sugar based transfer enzyme gene inter species and intra species differences exist in the composition.
These findings lay a good foundation in terms of reveal the activated sludge microbial micelle formation mechanism and the removal of nitrogen and phosphorus removal technology. For the activated sludge bulking control, excess sludge reduction and resource utilization of new technology development has reference significance.