Study On Nitrogen Renmoval In PAC And Bentonite Strengthened SBR System

With the increment of water pollution, eutrophication, water-saving problems and a public awarenessof environment, more and more countries and regions have formulated strict emission standards for nitrogen. Therefore research and development of high-effect technology of nutrient removal wastewater treatment become the focus of subject in the field of water pollution control projects.This paper intended to add powder activated carbon (PAC) and the bentonite in SBR (Sequencing Batch Reactor), respectively and discuss the effectiveness and feasibility of nitrogen treatment by powdered activated carbon and bentonite enhanced SBR. It also studied the Ammonia-nitrogen degradation dynamics process, and the impact of powder activated carbon and bentonite over nitrification bacterium growth and the sludge proliferation.(1)PAC and bentonite could adsorp ammonia, and the latter's adsorption was significantly better than the former.(2)Ammonia nitrogen and total nitrogen removal rates of PAC-SBR system were maximal, reaching 96% and 30% respectively, it followed by bentonite-SBR system, of which ammonia nitrogen and total nitrogen removal rates were 92% and 24%; in contrast, ammonia nitrogen and total nitrogen removal rates of conventional SBR system were 84% and 18%. The results showed that dosing PAC and bentonite, not only enhanced the system's nitrification function, but also contributed to denitrification reaction, thus improving the system's total nitrogen removal capacity.(3) When the reactors worked, the average oxidation rates of NH4+-N and NO2--N of three devices all displayed an upward trend:Among them, the fastest growing was the activated sludge in PAC-SBR system; it followed by activated sludge in bentonite-SBR system; finally it was activated sludge in conventional SBR system. Thus, dosing PAC and bentonite were associated with the improvement of the nitrosation activity and the nitrification activity of sludge.(4)The study of degradation dynamics in nitrogen degradation process of three devices showed that the saturation constant ks of PAC-SBR and bentonite-SBR processes was higher than that of conventional SBR process. Namely, under the same conditions, PAC-SBR and bentonite-SBR processes spent less time on removing the same amount of nitrogen than SBR system did. Consequently, from the kinetic point of view, the dosage of PAC and bentonit to SBR could improve the nitrogen removal rate of microbe treatment system.(5)The values Y and Kd of PAC-SBR and bentonite-SBR system were higher than those of SBR progress. This result showed that PAC and Bentonite had significant effect on the microbial growth kinetics.