Combined chemical conditioning method for deep drying of dehydrated sludge

Abstract

The invention discloses a combined chemical conditioning method for deep drying of dehydrated sludge. The method comprises steps as follows: to-be-treated dehydrated sludge is diluted with water, so that the moisture content of the dehydrated sludge is 90%-93%, strong acid is added to adjust the pH value to range from 4 to 5 after dilution, then potassium ferrate with the adding amount accounting for 0.1%-0.5% of that of absolutely dried sludge amount is added in the form of a solution with the mass percent concentration of 0.5%-2% and the pH value of 9-11, and oxidation treatment is finished after stirring for full reaction; then poly-aluminum chloride salt with the adding amount accounting for 4%-10% of that of absolutely dried sludge amount is added for coagulation treatment; then calcium hydroxide with the adding amount accounting for 0.3%-1% of that of absolutely dried sludge amount is added to adjust the pH value to range from 6 to 7, finally, poly-quaternary ammonium salt with the adding amount accounting for 0.1%-0.3% of that of absolutely dried sludge amount is added for filtration aiding, and chemical conditioning is finished. Through optimized combination of dilution, acidification, oxidation, coagulation, flocculation, filtration aiding and the like, the effect of bound water on sludge can be reduced, indexes including specific resistance of sludge, compressibility, hydraulic characteristic and the like can be improved, the proportion of releasable free water can be effectively increased, and the sludge dehydrating effect can be improved.

Description

Technical field [0001] The invention relates to the field of dehydrated sludge treatment, in particular to a combined chemical conditioning method for deep drying of dehydrated sludge. Background technique [0002] Sludge is a product in the process of sewage treatment. Generally, the treated sludge (dewatered sludge) discharged from urban sewage treatment plants is a semi-solid substance with a water content of 75-85%, which is mainly composed of organic debris, bacterial cells, and inorganic The composition of particles, colloids and agents used for flocculation is a complex mixture. The dewatered sludge is rich in organic matter, salt and a large amount of phosphorus, nitrogen and other toxic and harmful substances in the sewage, as well as virus microorganisms, parasite eggs, heavy metals and other toxic and harmful substances. Land, and with the infiltration of leachate and the spread of bacteria in the air, it causes considerable harm to the ecological environment. [0003]...

AI Technical Summary

Problems solved by technology

Dewatered sludge is rich in organic matter, salt, a large amount of phosphorus, nitrogen and other substances in sewage, as well as toxic and harmful substances such as virus microorganisms, parasite eggs, and heavy metals. Land, and with the infiltration of leachate and the spread of bacteria in the air, it causes considerable harm to the ecological environment