System and method for promoting hydrolysis of PAM (polyacrylamide) in dewatered sludge and simultaneously producing short-chain fatty acids

Abstract

The existing PAM (polyacrylamide) dewatered sludge has poor digestion efficiency due to oversize flocs in the anaerobic digestion process, thereby inhibiting the high-molecular organic matrix in the sludge from leaching, prolonging the retention time of the sludge, and providing possibility for degradation of PAM into the monomer acrylamide. The invention provides a recycling harmless system and method for promoting hydrolysis of residual PAM in dewatered sludge and simultaneously producing short-chain fatty acids, belonging to the field of sludge treatment and disposition. The method comprises the following steps: PAM dewatered sludge is subjected to pyrohydrolysis treatment to promote PAM flocs in dewatered sludge to dissociate; alkaline conditioning is carried out to sufficiently destroy the pyrohydrolysis sludge zoogloea floc structure; and the sludge is sent into an anaerobic fermentation tank to produce short-chain fatty acids. The method enhances the PAM hydrolysis rate, lowers the PAM potential toxicity, and implements recycling harmless utilization of PAM dewatered sludge.

Description

technical field [0001] The invention relates to the field of sludge treatment and disposal, and specifically refers to a resource-based and harmless system and method for promoting the hydrolysis of residual PAM in dewatered sludge and simultaneously producing short-chain fatty acids. Background technique [0002] At present, urban sewage treatment plants mostly use the activated sludge method to treat sewage. During the treatment process, a large amount of excess sludge will be generated, and the treatment and disposal costs are relatively high. However, the excess sludge contains a large amount of organic matter such as protein and polysaccharide, which can be It is converted into volatile short-chain fatty acids by anaerobic fermentation technology. Volatile short-chain fatty acids produced by hydrolytic acidification are mainly C2-C6 short-chain organic compounds (acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, and valeric acid, etc.), which ...

AI Technical Summary

Problems solved by technology

The system combines thermal hydrolysis technology and alkaline fermentation technology. On the one hand, thermal hydrolysis promotes the dissociation of PAM flocs in dewatered sludge, reduces the size of flocs, and increases the contact area of ​​subsequent treatment of dewatered sludge. During alkaline conditioning, the size of sludge flocs can be further reduced, and even the sludge flocs can be cracked, so as to promote the dissolution and hydrolysis of macromolecular organic matter in dewatered sludge, and increase the amount of acid produced by fermentation, so as to solve the problem of anaerobic digestion of existing dewatered sludge. During the treatment process, PAM seriously inhibits the hydrolysis of excess sludge and PAM secondary pollution and other problems

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