Study On Treatment Of Wastewater Containing High Concentration HPAM By Anaerobic Baffled Reactor

With large-scale exploitation of oil, polymer flooding oil recovery has beenwidely used, which is one of the most effective techniques of tertiary oil recovery. Buta great deal of produced water containing partially hydrolyzed polyacrylamide(HPAM) followed. HPAM wastewater has high viscosity and difficult tobiodegradation, it will pollute the environment as the long-term accumulation.Therefore, it is urgent to effectively treat the HPAM-containing wastewater.In the thesis, two strains of functional degradation bacterium cryopreserved inthe laboratory were selected to deal with high concentration HPAM-containingwastewater. The degradation condition was optimized and the degradation efficiencywas investigated. The expanded experiment was carried out in an anaerobic baffledreactor (ABR). The function degradation bacterium and anaerobic granular sludgetaken from Qingdao ShaZiKou sewage treatment plant were put into ABR for HPAMwastewater degradation. All the conclusions were as follows:(1) In the experiment, the conditions of different bacteria strains (PM-2, PAM-F1and the mixed two strains) were optimized, and the effect of the sole anaerobicgranular sludge on the HPAM removal efficiency was investigated as well as usingbacteria strains as co-substrate conditions. Optimum HPAM biodegradationconditions were as follows: continuous activating times3, inoculation5%(w/v),temperature35-40C, and initial pH6.5-8.0, degradation time7d. Under the bestconditions, the removal rate of mixed bacteria strains was better than the sole bacteriastrain, which could reach up to37.39%. The best removal efficiency of anaerobicgranular sludge was above46%, while under the co-substrate condition, HPAMremoval rate could reach up to58.46%. All the results reflected that it could reach upto a better HPAM removal rate when under the together conditions of the bacteria inthe sludge and the functional bacteria.(2) The effects of reflux ratio and hydraulic retention time on the treatment of 500mg·L-1HPAM wastewater were investigated. With increasing of reflux ratio orshortening of hydraulic retention time, HPAM and CODCrremoval rates increased tosome extent, and pH value and VFA concentration were also changed. Overallconsideration, the optimum best degradation condition for the operation of ABR wasreflux ratio10:1and HRT for24h. Otherwise, the removal rates of the first twocompartments have absolute predominance in HPAM removals when under the highreflux ratio or long HRT, otherwise, The HPAM degradation of ABR will removebackwards, the third and fourth compartments take on more work.(3) The treatment efficiency of wastewater containing high concentration HPAMbased on an ABR was studied, including of the variations of HPAM and CODCrremoval rates, redox potential and pH value. The results showed that HPAM andCODCrremoval rates of500mg·L-1wastewater were75.48%and85%, whichdeclared that ABR reactor was effective to deal with high concentrationHPAM-containing wastewater. The variations of VFA concentration and pH value inthe reactor showed that ABR has a strong ability to self-restore.(4) According to IR analysis of HPAM samples before and after biodegradation,microorganisms could degrade HPAM and utilize part of the amidogen and carbon fortheir growth, and inferred that the HPAM degradation process occurs in stage ofhydrolysis. SEM and HPLC analysis showed that macromolecular HPAM wasdegraded into micromolecular compound. Furthermore, sludge granules’ structurewere observed within the ABR by SEM. Mature granular sludge were formed, andthey could adapt to the conditions of the simulate wastewater, effectively degrade theHPAM in the wastewater and provide favorable conditions for the growth andreproduction of strains.(5) Dynamic characteristic of the treatment process of HPAM containingwastewater based on an ABR was grading studied. The researches showed that thedegradation of substrate pseudo-first-order kinetics characteristics. The degradationkinetic parameters of three levels were as follows: Vmax1=2.463d-1, KS1=12132.3mg·L-1; Vmax2=1.2016d-1, KS2=3081.6mg·L-1; Vmax3=0.9476d-1, KS3=3078.38mg·L-1. (6) HPAM removal rate of71.81%and CODCrremoval rates of71.93%could begained under the best condition of Fenton oxidation treatment of500mg·L-1HPAMwastewater:5.3mmol/L H2O2,1.44mmol/L Fe2+, pH3.0and30°C. Moreover, theinfluence of parameters on CODCrand HPAM removals followed a decline order of[H2O2]>[Fe2+]> pH> temperature.(7) The treatment of HPAM wastewater by combined Fenton oxidation andanaerobic biological processes was studied. Through the Fenton oxidation an ABRbiological process, the total CODCrand HPAM removal rates were increased due tothe enhancement of biodegradability by Fenton oxidation. Compared with single ABRbiological treatment process, FT-IR, SEM and HPLC analysises displayed that thecombined treatment process could degrade the macromolecular HPAM intomicromolecular compound, which was more broken and more thorough.