Study On Effect Of Organic Macromolecule Flocculant PDMDAAC-VP-FA On Sluge Dewatering Performance

with the rapid development of social economy, industry andagricultural intensification is greatly improved. Sewage treatments process a largenumber of waste water,and it will produce large amounts of sludge. Sluge treatmentand disposal is a hotspot of research, at the same time, it is a world problem. Thispaper is mainly research the effect of copolymer PDMDAAC-VP-FA which iscomposed of two dimethyl diallyl ammonium chloride, N-vinyl pyrrolidone, fumaricacid on the dewatering of sewage sludge.The experiment has worked with the following respects:1. Selected three different monomer ratio organic amphoteric flocculantsDMDAAC-VP-FA, respectively, No.1, No.2, No.3. Using orthogonal test method totest the pressure, flocculant, dosage as factors, choosing L9(34) orthogonal table, thespecific resistance of sludge as the index of each factor, analyzed the experimentalresults by visual analysis. Test results showed that: flocculant dosage range of R was1.37, the pressure R was0.46, and the flocculant R was0.32, so the relationshipbetween primary and secondary influence factors of fluctuation to sludge dewateringwas the flocculant dosage, test pressure and flocculant; The best dosage of flocculentwas8mg/L; The most appropriate pressure was35Kpa;The best flocculant todewatering effect was No.1, No.2and No.3followed.2. Do Sludge dewatering performance research by natural filtration and vacuumpressure filtration method with No.1flocculant. Drew the constant pressure filtrationfiltrate volume of t/V~V diagram,and obtained the linear slope K. And gained thespecific resistance of sludge by filtrate viscosity、moisture content of filter cake and soon. The original sludge specific restistance was11.8*1012m/kg. With the addition of flocculant, sludge specific resistance decreased. when the flocculant dosage was8mg/L, specific resistance of sludge was reduced to the lowest of2.7*1012m/kg.Afterthat,with the increase of flocculant,the sludge specific resistance rose instead, theflocculant showed the excessive phenomenon.3. Morphology of before and after treatment sludge cake were observed byscanning electron microscopy (SEM). Using the nonlinear mathematical fractal theoryand Sand box counting method to map relations betweenln Nandln to obtainfractal dimension of various forms (Df). Results showed that: adding No.1PDMDAAC-VP-FA flocculant the sludge cake became large and had dense structure.By linear diagram of slope,we can obtained the fractal dimension (Df) of blank sludgewas0.8249. Adding8mg/L flocculant the fractal dimension(Df) of sludge was0.7186.4.Research the synergistic effect of lime and the flocculant on sludge dewateringperformance. When2gCaO was added,the filtration volume was90mL, the sludgeresistance was reduced to2.4*1012m/kg；When adding3gCaO, sludge filtrationfiltrate volume decreased with the increase of CaO, the specific resistance of sludgeincreased. The experimental results showed that, appropriate amount of lime canproduce synergistic effect with flocculant, effectively improve the sludge dewateringperformance.5. We did field tests in three sewage treatment plants No.1flocculant, whichused belt type filter press、centrifugal type filter press and plate type filter pressrespectively, but the test results were not ideal. And we analyzed the causes of thefailure of the experiments.