Method for recovering phosphorus resource in municipal excess sludge

Abstract

The invention discloses a method for recycling phosphorus resources in municipal excess sludge. The method comprises the following steps: (1) feeding part of sludge into a pretreatment reaction tank for pretreatment; the amount of the exported sludge is 30%-60%; adding an oxidizing agent for oxidation reaction; (2) reducing the water content of the residual sludge to 96-99% in a fermentation tank in a gravity concentration manner, and adjusting the pH value of the residual sludge to 9-12; (3) mixing the pretreated sludge and residual sludge with the moisture content of 96-99% according to the volume ratio of (2: 1)-(4: 1), and performing anaerobic fermentation for 30-56 hours; (4) adding rhamnolipid, wherein the addition amount of rhamnolipid is 0.025-0.1 g/g of TSS; and (5) phosphorus absorption: taking the fermentation supernatant, adjusting the pH value to 9-11, adding magnesium salt into a fluidized bed according to the molar ratio of phosphate to 1.5: 1-2.0: 1, producing struvite crystals, and separating under the action of gravity to realize the recovery of phosphorus and nitrogen in the supernatant. According to the method for recycling the phosphorus resource in the municipal excess sludge, secondary pollution is avoided, and the phosphorus resource in the sludge is recycled to the maximum extent.

Description

technical field [0001] The invention relates to the technical field of sewage plant sludge treatment, in particular to a method for recovering phosphorus resources in municipal surplus sludge. Background technique [0002] The output of surplus sludge in my country is large, and more than 90% of phosphorus in sewage is enriched. The phosphorus recovered from municipal sludge can meet 15%-20% of the global demand for phosphorus. Taking sludge as a potential phosphorus source and recovering phosphorus resources from it can solve the problem of environmental pollution to a certain extent on the one hand, and alleviate the shortage of phosphorus resources on the other hand. [0003] The premise of phosphorus recovery is to release the phosphorus in the sludge from the solid phase to the liquid phase, so as to carry out the next step of recovery. In view of this, improving the cracking degree of sludge to release more phosphorus has become the focus of research in this field. R...

AI Technical Summary

Problems solved by technology

However, chemical surfactants in the method of promoting acid production by anaerobic fermentation of excess sludge are toxic and non-biodegradable, causing secondary pollution to excess sludge

However, the addition of chemical reagents not only increases the consumption of energy and the cost of the treatment process, but also produces secondary pollution to a certain extent.