Patent ID: 11970415
Assignee: ZHEJIANG UNIVERSITY
Field: Environmental technology (Chemistry)
Classification: CPC C | IPC C

Claim 10:
11. A sludge anaerobic fermentation treatment method with simultaneously enhanced acid production and phosphorus removal and a reduced concentration of adverse by-products, comprising the following steps:
(1) allowing waste activated sludge to stand for 24-36h to stabilize and concentrate the sludge, wherein the concentrated waste activated sludge has a concentration of a total suspended solid TSS of 10000-30000 mg/L and a concentration of a volatile suspended solid VSS of 4000-18000 mg/L; adding the concentrated waste activated sludge into an anaerobic reactor; and
(2) adjusting a pH value of the concentrated waste activated sludge to 10±0.1 with a sodium hydroxide solution, and then adding a modified magnetic powder into the waste activated sludge in the anaerobic reactor, wherein an addition amount of the modified magnetic powder is 0.2-0.6 g/gVSS; introducing nitrogen into the reactor for 5-15 minutes to remove air in the reactor, sealing the reactor, and performing fermentation under stirring at a rotating speed of 60-120 r/min at a fermentation temperature of 30-35° C. for a stirring time of 10-15 days, while always maintaining the pH value of sludge at 10±0.1 during the stirring and the fermentation; and after the reaction is finished, separating the modified magnetic powder from the sludge by using a magnet,
wherein the modified magnetic powder is prepared by a method comprising: placing and continuously stirring powdery magnetite in a reaction kettle while continuously adding a sulfuric acid solution of 93%-98% into the reaction kettle by atomization to form a porous structure on a surface of magnetite powder through reaction of the atomized sulfuric acid with magnetite powder, thus obtaining a modified magnetic powder, wherein the sulfuric acid solution is added into the reaction kettle at a speed of 5 L/100 kg magnetite powder per hour, a mass ratio of the sulfuric acid solution to the magnetite added in the reaction kettle is 6-24:100, and a total time of stirring and reaction of the sulfuric acid and the magnetite is 5h.