Study On The Intensification Of Acid Production By Anaerobic Fermentation Of Residual Sludge

The anaerobic fermentation of residual sludge is an effective method for sludge reduction at present.In the process of anaerobic fermentation of residual sludge,there will be a valuable intermediate product:Volatile Fatty Acids(VFAs).On the one hand,it can be used as an organic carbon source by nitrogen and phosphorus removal microorganisms to improve the efficiency of nitrogen and phosphorus removal;On the other hand,it can also be used as a chemical raw material to produce some high value-added chemical products in the industrial field.Therefore,this paper discusses some appropriate methods and techniques to affect the process of fatty acid production by residual sludge fermentation,the large molecular organic matter in the reaction process is converted to the available VFAs to a great extent.This can not only reduce the harm to the environment,but also open up a good way for the recycling treatment of waste sludge to resources and reduction.Based on the anaerobic digestion process of excess sludge,the enhanced acid production under three treatment conditions,including hot alkali pretreatment,methane production inhibitor and surfactant addition,was studied.Every 12 hours for the anaerobic fermentation reactor for fermentation liquid analysis test,measurement index projects conclude:TCOD,TN,TP,VSS,TSS and VFAs,on the basis of data analysis and research results,we systematically investigated the effect of three different conditions of sludge anaerobic fermentation effect.Then the hot alkali pretreatment enhanced acid production research,selection of processing conditions:pH=12,temperature=70,processing time=2h hot alkali pretreatment technology.TN,TP,TCOD,VSS,TSS and VFAs In the fermentation liquid had concentration compared with the blank experiment under the environment of the control group improved significantly.Hot alkali pretreatment for sludge anaerobic fermentation is the most obvious,the concentration of VFAs reached the maximum 885mg/L after fourth days,the hot alkali pretreatment technology can promote sludge anaerobic fermentation.Then,a methanogenic inhibitor was used to enhance the production of acid.A suitable 0.012%(the volume ratio of sludge fermentation solution)dosage of chloroform(inhibiting the activity of methanogenic bacteria)and lOg barium chloride(inhibiting the activity of sulfate reducing bacteria)were added to zymotic fluid,as an inhibitor.The concentration of TN,TP,TCOD,VSS,TSS and VFAs in the fermentation broth was greatly improved compared with the control group under the natural environment.After adding methanogenic inhibitor,the maximum VFAs in the excess sludge anaerobic fermentation liquor reached sixth days,corresponding to 800mg/L.Adding methane inhibitor could promote the anaerobic fermentation of excess sludge to produce acid.At last,the amphoteric imidazoline(hydroxymethyl amphoteric imidazoline)was added to enhance the acid yield of the amphoteric imidazoline(the ratio of dosage and dry weight of sludge was 0.02g/g).Comparing to the control group under the natural environment condition,TN,TP,TCOD,VSS,TSS and VFAs in fermentation liquid had more concentration.The maximum concentration of total VFAs adding imidazoline amphoteric surfactant sludge produced by 685mg/L,appeared on the 5.5 day,the surfactant can promote sludge anaerobic fermentation.