Experimental Investigation Of The Microbubble System Used In Biofilm Reactor For Rural Domestic Sewage Treatment

Water resources demand problem is getting worse, how to effectively remove the pollutant of sewage is very important. Different from urban sewage, the rural domestic sewage treatment must connected with the reality of the situation. This study chose biological effect for country sewage treatment, mainly about the contrastive study of the carriers and the using of the microbubble system to improve the performance of biofilm reactor.The effects of carriers used in Sequencing Batch Biofilm Reactors for country sewage treatment, was investigated. The parallel experiments which aimed to compare the effect of biofilm culturing and biological disposal capacity were carried out to select the best carrier which can substantially optimize the performance of the reactor. After adding immobilized carriers into the bio-reactor, the results showed that the effect of the carbon fiber packing was the best, COD removal rates could reach to 100% and NH4+-N removal rates could reach to 92.3% when aeration time was 5hours. The pollutants removal effect of the carriers is decreased in the order of the carbon fiber, the combined packing, Sponge packing and the web-like packing.After selected the best carrier, the optimal operating conditions of biofilm reactors were investigated. Results showed that hydraulic retention time with 12 h and organic loading lower than 500 mg/L with 2-4 packing in the reactors were the best operating conditions, the contamination removal efficiency was ideal.Synchronous fluorescence spectroscopy and three-dimensional fluorescence spectroscopy indicate that the fluorescent molecules have strong protein-like fluorescence and obvious humic-like fluorescence. The result suggested that the substances of small molecule was cleavaged in the reactor with ordinary bubbles, the degree of aromaticity increased with the reacting time, and the removal efficiency of proteinaceous materials was ideal, whereas in the reactor with microbubbles, the content of humic and protein-like both increased with the reaction time, suggested that the reactor with microbubbles can improve the degree of biochemicalization. The UV-Vis spectroscopy the results again.The biggest problem encountered in this process of the experiment is the lower removal rate of phosphorus. According to the analysis of all aspects , the reasons of lower TP removal rate in biofilm reactor: high reacting temperature, high DO concentration, overload of ammonia nitrogen concentration of the influent, too little sludge.