Patent ID: 8641907
Filing Date: 2014-02-04
Classification: C02F

Abstract:
1. A method of recovering polyhydroxyalkanoates (PHAs) from municipal waste sludge, comprising: (a) removing coarse particles in the municipal waste sludge and measuring a mass of a solid content in the municipal waste sludge in terms of a volatile suspended solid in the municipal waste sludge; (b) removing a supernatant from the municipal waste sludge; (c) freezing the municipal waste sludge to deactivate polyhydroxyalkanoates (PHAs) producing microbial species present in the municipal waste sludge; (d) adding a controlled amount of sodium hypochlorite solution to the municipal waste sludge that has been frozen to digest the PHAs producing microbial species, wherein a ratio of the mass of the solid content of the municipal waste sludge to a volume of the sodium hypochlorite solution added ranges from 0.67 mg/ml to 4 mg/ml; and (e) separating PHAs from non-PHAs substances in the municipal waste sludge obtained in step (d).