| In the current, sewage treatment plants in China were mainly given priority to withbiological denitrification and phosphorus removal. However the treatment effect wasnot ideal because the concentration of organic matters in wastewater was low. In thisstudy, a submerged membrane bioreactor（MBR）was applied to the treatment of lowloading campus wastewater from Xi’an Siyuan University. First, analyze the transferrule of pollutants and membrane fouling characteristics during launch process ofmembrane biological reactor. Then, aimed at the problem of a high content of nitrogenand phosphorus in the reactor effluent, the carbon source was extracted throughanaerobic fermentation at the condition that the kitchen waste was inoculated withsludge, focusing on the effect of dosing kitchen waste fermented product on the removalefficiency of pollutants in the MBR and sludge characteristics, as well as characteristicsof membrane fouling. The main research results were as follows:（1）Starting phase stain removal performance analysis shows, the MBR could get agood removal effect of COD. In the early start, the contribution rate of membranereached around37%. With the biomass increasing, biological removal rate rose to95%from63%, while interception of membrane correspondingly weakened. Theconcentration of ammonia in the effluent was below1mg/L. Although the removal rateof system for TN and TP removal rate increased, the overall treatment effect was notideal. Sludge concentration (MLSS) gradually increasing as operation time, andpresented a modest inflation, but had no effect on organic matter removal effect. Whenthe launch process ended, the phenomenon that the film was polluted appeared. Mixture characteristic analysis showed that protein content of SEPS increased considerably,making bigger contribution to membrane fouling.（2）By batch experiments on extract carbon source through anaerobic fermentation atthe condition that the kitchen waste was inoculated with sludge to research the influenceof the main factors (temperature and pH) in kitchen waste fermentation process.Temperature had a significant influence on hydrolysis acidification effect of kitchenwaste, hydrolysis rate would increase with the rising of temperature. Acidification effectincreased with the rising of temperature when the temperature was below37℃rise,but the situation was opponent under the condition of high temperature. At theconditions of different temperatures, the main component in the VFA was acetic acid,and the content of lactic acid content was high. So the most suitable hydrolysisacidification temperature is37℃.Under the condition of natural fermentation, the pHwas low, and hydrolysis acidification effect was not ideal. So the pH was adjusted to6,the highest hydrolysis rate increased, mainly coming from hydrolysis of carbohydratesand protein. Maximum VFA concentration increased, the main composition was aceticacid. Considering effectiveness and cost, the suit conditions are33℃and controlled pH.（3）Experimental results showed, organic matter concentration increases in the MBRinfluent after dosing kitchen waste fermented liquid, which had little effect on COD andNH4+-N removal, with effluent concentrations of them were less than20mg/L and1mg/L, respectively. Adding external carbon obviously improved the removal ofnutrients, with TN and TP average effluent concentrations decreasing from18.7mg/Land1.8mg/L to7.6mg/L and0.9mg/L, respectively. Moreover, sludge properties such asMLVSS/MLSS increased from54%to65%, sludge growth rate accelerated, and settlingability increased, while EPS content decreased and protein reduced more,polysaccharide also decreased. After adding the kitchen waste fermented liquid, themembrane fouling was more likely to form because of the activated sludge in themixture, it may be due to oil material easily adsorbed on the membrane, contaminatingmembrane, so the issue deserves further attention in actual application process. |
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