Study On The Mechanism Of Uncoupling Agent TCS To Enhance Sludge Reduction And Conditioning Dewatering

With the quickening pace of urban wastewater treatment plant construction,sludge treatment and disposal has become a concern.Activated sludge is widely used in wastewater treatment and plays a key role in wastewater purification.Due to the nature of sludge itself,its moisture content reaches more than 99%.The large volume limits the follow-up disposal of sludge,sludge reduction becomes the key direction of sludge treatment,and sludge dewatering becomes the key link.Due to the high compressibility of the sludge,extracellular polymers substances?Extracellular polymeric substances,EPS?and other properties,direct dewatering can not effectively remove the free water and the bound water,the moisture content is still as high as 90%,unable to achieve effective sludge reduction.In order to improve the efficiency of sludge dewatering,conditioning and dewatering can improve the structural characteristics and physicochemical properties of sludge.The main methods of conditioning include physical,chemical,biological or combined conditioning.With the widely of the research on sludge,energy uncoupling technology is used to realize sludge reduction gradually,but can be effectively applied to strengthen the sludge dewatering,there is no related research at home and abroad,this topic is reasonable to use reagent 3,3',4',5-tetrachlorosalicylanilide?3,3',4',5-Tetrachlorosalicylanilide,TCS?,combined with inorganic coagulants FeCl₃(Fe³⁺)was carried out by the TCS strengthen the study of sludge reduction with conditioning and dewatering.The effect of uncoupling agent TCS on residual sludge properties and sludge reduction was first investigated.The results showed that adding TCS could reduce the content of ATP in sludge cells,simultaneously reduce the sludge concentration and sludge yield,increase the sludge reduction rate and reduce the biomass of sludge,and the sludge reduction rate could reach up to 39.3%.TCS promotes release of soluble microbialproduct?Soluble microbialproduct,SMP?in sludge mixture,inhibits the increasing of EPS,promotes the conversion of hard-to-remove bound water to free water in sludge at a maximum of 3 percent,reduces sludge particle size,changes the biological phase of the sludge and increases flocculation granulation.Secondly,the influence of coupling agent TCS and its coupling Fe³⁺ on sludge dewatering performance was studied.The results showed that TCS combined with Fe³⁺ conditioning could further reduce EPS secretion and improve the ability of bound water into free water,with the conversion ratio up to 4%.Compared with the single action of TCS,the coupling Fe³⁺ can agglomerate sludge particles and increase the size of floc.Moreover,the looser the flocs are,the stronger the binding ability of the floc particles and Fe³⁺ is,and the larger the average particle size of the floc is formed.The function of TCS adding alone,can enhance the specific resistance to filtration?Specific resistance to filtration,SRF?and sludge mud cake moisture content that do not favor the sludge dewatering,when coupling Fe³⁺,it can make the sludge SRF value decreased significantly,the greater the concentration of TCS,the smaller the SRF,compared to the TCS adding alone effect,reduce the amplitude,the greater the biggest can reduce 17.9 times,mud cake moisture content reduce,strengthen the sludge dewatering performance.When analyzing the organic components of filtrate,it was found that the filter paper had stronger retention ability under the coupling of Fe³⁺.In addition,the effect of energy uncoupling TCS coupling enhanced coagulation to improve sludge dewatering performance was studied in this paper.Results show that adding the TCS,under the condition of coagulation enhanced,compared with the single coagulation enhanced,could inhibit the secretion of EPS,increasing the floc size,enhance the capacity of combined water into free water,SRF to better reduce the sludge and mud cake moisture content,Fe³⁺ concentration is higher,the better the results,the free water was 80.7%,and the largest proportion of SRF biggest reduces 98.2% compared with the blank group,further strengthen ability of sludge dewatering.When analyzing the organic components of filtrate,it was found that the filter paper had stronger retention ability under the TCS environment.In conclusion,the addition of TCS into sludge had a significant effect on the reduction of residual sludge,and can inhibit the secretion of sludge EPS and increase the free water content,but it cannot effectively reduce the sludge SRF and sludge cake moisture content,which is not conducive to dewatering.The coupling of Fe³⁺ can further inhibit EPS secretion,strengthen the combined water transformation,improve the size of floc,effectively reduce the sludge SRF and sludge cake moisture content,and enhance the sludge dehydration performance.Moreover,the higher the concentration of Fe³⁺,the better the effect.