The Application Study On A/A/MBBR Process Used For The Modification Of Wastewater Treatment Plant

With the rapid development of urbanization, the continuous increase of sewage dischargequantity, water resources are polluted seriously resulting into the water crisis in terms of waterquality. The direct way resolves the problem is make sewage become the second waterresource by raising the treatment quantity of wastewater, increasing the treatmentefficiency of sewage treatment plant. The study presents one new compound biological treatmentprocess of Anaerobi-anoxi-moving biofilm.The core part of the A/A/MBBR process is fluidized carriers. Compared to normalpolyacrylic ladder hoop packings, the biofilm of modified polypropylene mediums ischaracteristic of high growth speed rate from the screen-sizing and evaluation for them.Moreover, the discharge requirement can be met in the condition of the residence time of 1.0hour the gas water ration of 4:1;COD removal rate is up to above 80% with packing rate of15%.Based on kinetics analysis for microorganisms growth and organisms degradation, it isfound that the system creates the highest oxidation speed rate of organism and ammonia underthe sludge age of 17 days condition. In addition, system oxygen consuming formula equation andhydraulic residence time and sludge age are deduced, which can be used for the empiricalformula for further project design.Average removal rate of BOD5, COD, TP, Ammonia and TN is up to 96.3%, 92.66%,81.77%, 97.95% and 84.53% respectively under the condition of hydraulic residence time of6.8h and dissolved oxygen of 1.5~2.5mg/L;and the effluent quality can meet the first class of Astandard. Without of the circumfluence of nitrifying liquid, average removal rate of Nitrogen andTN is 94.7% and 70.2%;and the effluent quality can meet the first class of B standard.Accordingly, nitrification and denitrification are took place simultaneously resulting from theformation of anoxic micro-environment and the action of heterotrophic nitrobacteria. During theperiod of experiment, different degree of simultaneous nitrification and denitrification arediscovered in the case of DO of 0.5～0.9mg/L, C/N of 15, organism of 5000mg/L, hydraulicresidence time of 5h, pH value of 7.0～8.0.According to the pilot-plant results , Modification project of the second treatment system inYingkou city is designed, which detailing BOD-SS load of 0.13 kg/kg.d, organism quantity of4500～5000mg/L, gas water ration of 4:1～5:1, sludge age of 17days. The removal rate ofBOD and COD is over 90%, and that of Nitrogen, TP and TP is up to 85%. The effluent qualitymeets the first class of A discharge standard, satisfying the requirement of being reuse waterresource.Applying A/A/MBBR process to the modification and argument of existing old assembly isone kind of competent and new processes for sewage treatment concerning China condition, bothtechnically and economically. This new process application fills up the blank in terms of theexpanding and modification to the existing old wastewater treatment plants and it is helpful forincreasing wastewater quality as well as reducing treatment costs, possessing significantmeaning for the development of environmental undertaking.