Establishment Of The Joint Model ASM1-SMP And Its Application In MBR

Membrane bioreactor (MBR) technology combines the biological degradation process by activated sludge with a direct solid–liquid separation by membrane filtration. The MBR has many advantages over conventional wastewater treatment processes .These include small footprint and reactor requirements, high effluent quality, good disinfection capability, higher volumetric loading and less sludge production . It's estimated that the MBR market value will rise to US$ 363 million by 2010 which shows an attractive market promise.However, the major drawback that the MBR filtration performance inevitably decreases with filtration time limits its further development. Current study shows that the soluble microbial products has high Correlation coefficient with MBR fouling, is one of the most important fouling materials, thus there's an urgent need for the establishment of a mathematic model that can predict this kind of material to further enhance the understanding of membrane fouling mechanism.This study was to propose a mathematical model ASM1-SMP by incorporating the concept of SMP into the activated sludge model (ASM) no.1 , broaden its applicability from conventional activated sludge process (CAS) to the membrane bioreactor (MBR) system. Firstly, an optimum operating condition was determined according to a series of parallel experiments which were different in set of SRT, further experiments and simulation was based on this result. A setup of model structure was illustrated afterwards, with details of rules obeyed and parameters added.To enhance the applicability of the model , the value of sensitive parameters was determined by experiment rather than taking default value in ASM1,μ_H,Y_H,b_H were measure by respiratory method,μ_A by high F/M method, for SMP, it was discussed as two parts including UAP and BAP. Equations were solved by Rounge-Kutta, based on the platform of Matlab. The model is able to predict the MBR water quality, its sludge production as well as the SMP concentration in the reactor. Results showed that the simulated values coincide well with the measured ones in respect of COD,NH4-N,NOX-N,MLSS and SMP. Having been proved to be a major component in supernatant that influence the sludge production, the production and degradation of SMP in MBR should not be ignored any more.