Modification Of Granular Conditioning Agent And Application In The Sludge Compost

Aerobic composting is one of the most commonly used methods of handlingexcess sludge, this method is a biochemical process that it transformates the organicmatter in the sludge into stable humus by the microorganisms widespread in nature. Butthe excess sludge of the characteristics of high moisture content and small porosity cannot meet the physical and chemical conditions required for composting, it generally canbe improved by adding flocculants. Flocculants include two kinds of organic andinorganic. Currently, organic conditioning agents, the most widely used, can regulate theC/N ratio, water content and physical structure of the body, and so on. Organicconditioning agent need to be modified in order to strengthen its roles. This topic studyto modification of the flocculants and application in composting. This experiment studyhas the conclusions as follows. Firstly, physical modification studying the density,porosity, properties of water absorption and loss, structural integrity of the flocculantstreated by different burst pressure,0.65MPa and0.7MPa are optimal burst pressures.Conclusions of the application in composting are as follows. Blasting flocculants isbeneficial to rapid warming and high temperature maintained. Ammonia emission canbe reduced, release amount of the experimental groups about1/2of the control group.Accelerate the reducing about moisture content in stockpile, at the end of thecomposting, heap material moisture content of two experimental groups are lower4.73%and4.83%than of the control group. Enhancing the ability of conditioning agentto absorbing water in the compost, two experimental groups flocculants moisturehighest appreciation are higher21.02%and21.05%than the control group. Conduciveto rapid degradation of organic matter, the organic matter of stockpile degradation ratesof two experimental groups are higher6.82%and5.84%than the control group,Without much impaction on the change in pH, oxygen and hydrogen sulfide content.Secondly, conditioning agent by chemical modified (carboxymethylation) shows thatsimulated ammonia absorption efficiency and water absorption are significantlyenhanced. Conclusions of the application in composting are as follows. Ammoniaemissions can reduced, the highest ammonia emission of experimental group is lower 873mg/L than the control group (883mg/L). Accelerate moisture loss of the stacker andincrease water absorption ability of conditioner in composting. The degradation oforganic matter can accelerated, organic matter degradation rate is higher3.4%in theexperimental group than in the control group. Changes in temperature, oxygen andhydrogen sulfide contents do not affected whether or not conditioning agent ofchemically modification. Thirdly, the study of conditioning agent of biologicalmodification process shows that bran group and vegetable waste group are similar,better effect than the mushroom group. Considering the bran about2yuan/kg cost, sovegetable waste is chosen as the best fermentation additive. Applied to Compost drawconclusions are as follows. In favor of the pile rapid warming and maintaining hightemperature period, the experimental group of high temperature period for3days，whilein the control group only lasts1day. pH value of the experimental group is lower1.92than the control group, proving the acidic substance of experimental group more thanthe control group. Reducing ammonia emissions, the highest emissions of ammonia inthe experimental group lower709mg/L than the control group(898mg/L). Acceleratingstockpile water losing, water content in the experimental group reduces more4.43%than control group. Conditioning agent of modification is beneficial to the degradationof organic matter，degradation rate in the experimental group higher9.5%than thecontrol group. But the experimental group and control group of the organic mattercontents are37.15%and36.43%at the end of composting. It indicates that conditioningagent by biological modified can accelerate the degradation of organic matter, butdrawback is that more organic matter come into the pile, burden to the degradation oforganic matter. Biological modification of flocculants or not dose not much effect on theoxygen and hydrogen sulfide contents in composting.