Anaerobic Digestion Sludge Condition By Oxidants-fe(ii)allied Enhanced Dewaterability: Performance And Mechanisms

As the speed of urbanization in China continues to accelerate,the amount of sewage continues to increase,forcing the construction of sewage treatment plants to accelerate,resulting in an increasing number of sewage treatment plants and a rapid increase in sludge volume.If these sludges are not properly and effectively treated,it is easy to cause damage to the environment and endanger human health.However,the moisture content of sludge after anaerobic digestion is generally above95%.Because the moisture content of sludge is too high,the sludge volume will be too large,which puts higher requirements on subsequent treatment costs and treatment sites.Therefore,improving the dewatering performance of anaerobic digestion sludge has become the only solution to this problem and an important means to alleviate the excessive growth of sludge treatment and disposal.However,the sludge dewatering performance after anaerobic digestion deteriorates,so how to improve the anatomy The dehydration performance of oxygen-digested sludge is a hotspot and a difficult point in the current environmental research field.At present,there are many methods for strengthening anaerobic digestion of sludge at home and abroad,mainly focusing on the treatment of sludge by heat treatment,pulsed electric field,ultrasonic,microwave,Fenton method,bioflocculant and the like.In this paper,from the perspective of engineering application,the method of anaerobic digestion of sludge with potassium permanganate/sodium hypochlorite-ferrous iron is studied,and the dewatering performance of sludge and its extracellular polymerization are studied in this way.The composition and distribution characteristics of the material were analyzed to analyze the changes in the morphological characteristics of the sludge flocs.The use of potassium permanganate-ferrous iron to adjust the anaerobic digestion sludge can effectively improve the dewatering performance,and determine the potassium permanganate dosage is 50mg/g TSS,potassium permanganate:ferrous iron stoichiometry is 1:At 5 o'clock,the best dehydration performance can be obtained;the mechanism of potassium permanganate-ferrous iron composite conditioning anaerobic digestion sludge is:after the oxidation of potassium permanganate,the sludge is cracked,and the polysaccharide in the extracellular polymer The removal effect is better than the removal effect of the protein.The macromolecular substance tends to transform into small molecular substances,some microorganisms are killed,the intracellular substance and the bound water are released,and the floc structure becomes loose;Iron and oxygen and the intermediate reduction product of potassium permanganate,Mn⁴⁺,react 10%of new ecological ferric iron in situ,and ferrous and ferric iron co-flocculate the sludge,strengthening the coagulation effect and improving Dewatering performance of anaerobic digestion sludge.The sodium chlorite-ferrous composite conditioning anaerobic digestion sludge can effectively improve the dewatering performance.When sodium hypochlorite is added separately,the optimal dosage is 75mg/g TSS;the optimum conditions for determining the dewatering performance in composite conditioning are:The sodium hypochlorite dosage is 125 mg/g TSS,the sodium hypochlorite:ferrous iron stoichiometric ratio is 1:5;the sodium hypochlorite-ferrous iron composite conditioning sludge makes the extracellular polymer of each layer soluble organic carbon,polysaccharide,and protein.It shows a downward trend;the mechanism of sodium hypochlorite-ferrous composite conditioning sludge is:the cracking effect of sodium hypochlorite,so that about30%of the microorganisms in the sludge are killed,and this part of the microorganisms release the intracellular substances and put in the ferrous iron.About 7%of the ferrous iron reacts with oxygen in the air to form a new ecological ferric iron,which strengthens the coagulation effect,and the sludge particles and the ferrous iron/new ecological trivalent iron flocculate and improve.Dehydration ability of anaerobic digestion sludge.