A method for recovering polysaccharides in extracellular polymeric substances

Abstract

The invention relates to a method for recovering polysaccharides in extracellular polymeric substances. The method includes S1) a step of collecting activated sludge; S2) a step of treating the activated sludge, namely a step of dissociating extracellular polymeric substances on surfaces of microbial cells in the activated sludge, and removing non-soluble impurities including cell bodies and cellresidues through gravitational setting or centrifugation to obtain a soluble extracellular polymeric substance solution; S3) a step of treating the soluble extracellular polymeric substance solution,namely a step of adding an ionizable high-valent metal salt or a solution containing high-valent metal ions into the soluble extracellular polymeric substance solution so that polysaccharides in the soluble extracellular polymeric substance solution react with the high-valent metal ions to form non-soluble suspended polysaccharides; and S4) a step of polysaccharide recovery, namely a step of intercepting the suspended polysaccharides after reaction with the high-valent metal ions in a manner of performing filtration on the non-soluble suspended polysaccharides, thus achieving an objective of recovering the polysaccharides in extracellular polymeric substances. The method for recovering polysaccharides in extracellular polymeric substances is convenient to operate, energy-saving and environmentally friendly.

Description

technical field [0001] The invention relates to a method for recovering polysaccharides in extracellular polymers. Background technique [0002] Resource recovery is an inevitable direction for the future development of sewage treatment. At present, the most commonly used sewage treatment technology is the activated sludge method, however, a large amount of excess sludge generated during the activated sludge treatment process is an urgent problem to be solved. The remaining sludge is mainly composed of cell bodies and extracellular polymers, of which the extracellular polymers account for 10-40% of the dry weight of the sludge. Extracellular polymers mainly include the secretions of microbial cells, cell autolysis or some substances shed from the cell surface, including polysaccharides, proteins, nucleic acids, phospholipids, humus, etc., among which polysaccharides and proteins are the main components. In particular, polysaccharides can be used as biological flocculants, ...

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Problems solved by technology

However, the above method may need to use various toxic solvents such as chloroform, or the material cost is high, or waste a lot of water resources, or waste a lot of energy, and there are problems such as chemical agent consumption, high energy consumption, and secondary pollution. Sustainable polysaccharide separation and recovery method, only suitable for small-scale extraction, not suitable for large-scale production

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