Study On The Adsorption Behavior Andmechanism Of Organic Matter By Aerobic Granules

Aerobic granular sludge has excellent biodegradability and adsorption capacity due to its porous structure. However, the adsorption mechanism of organics is still to be discussed. Based on the PCR-DGGE technology, the influencing factors and adsorption mechanism of the adsorption of organic compounds by aerobic granular sludge have been discussed in this paper. The above research is helpful to optimize the operation parameters of aerobic granular sludge system, which has practical significance for the stable and efficient operation of aerobic granular sludge treatment system.The conditions of optimal adsorption performance of organic pollutants by aerobic granular sludge was obtained by studying the influencing factors of adsorption. The adsorption rate of COD can reach 70% when the sludge particle size is 0.3-1.0 mm, sludge concentration is 3000 mg/L, EPS content is more than 195.08 mg/gVSS, wastewater concentration is 1500 mg/L, static adsorption time is more than 18 h, pH value is 7.0-9.0, temperature is 30℃, stirring intensity is 150 r/min.The COD removal efficiency during the initial adsorption is obvious. The adsorption of organic pollutants by aerobic granular sludge is a process of spontaneous, endothermicand entropy increase, in which the physical adsorption plays a significant role and the biological and chemicaladsorption as supplement. Freundlich adsorption isotherm can better describe the adsorption process,which is multilayer adsorption. Diffusion between particles and Pseudo-second order kinetic model can well describe the adsorption process,which indicates that the main limiting stage of the adsorption of organic pollutants by aerobic granular sludge was the pollutants diffusion process in the granular sludge and the binding process between pollutants molecular functional groups and adsorption site,and the latter has a greater impact.In order to study the microbial mechanism of adsorption by aerobic granular sludge, community changes of aerobic granular sludge in the adsorption process were analyzed by PCR-DGGE.The results showed that the microbial population structure of aerobic granular sludge was closely related to the wastewater quality, and the performance of aerobic granular sludge was determined by the population structure.The quantity of Candidatus Saccharibacteria bacterium was increased in the treatment of organic wastewater containing phenol, which showed that it could promote the adsorption of phenols in wastewater. The number of Propionibacteriaceae bacterium increased and Actinobacteria VeSm15 appeared in the treatment of organic wastewater containing heavy metals, which indicated that the two strains have a strong capability to withstand heavy metal resistant load and are conducive to the adsorption of heavy metal ions.