| At present, water environment pollution has become one of the hot topics in the world, while the remaining sludge treatment and disposal has become the constraints of urban sewage treatment a bottleneck in the development of the industry, how to resolve the problem of excess sludge production from the source is the urgent requirement of the environmental protection workers.This paper studied the SBR/OSA process (OSA process deformation) and reference system of SBR process, then the two processes of sludge reduction and nutrient removal were investigated, and the reasons affecting the sludge reduction are analyzed.To explore the activated sludge samples that the biological sludge phase characteristics and the characteristics of the sludge in the main reaction zone under different SRT condition. Combined with the principle of sludge decay to analyze SBR/OSA sludge reduction, and we explored the SBR/OSA sludge reduction sludge adsorption properties of each work area and mixed adsorption effect. Now a certain effect on the reduction of excess sludge yield of SBR/OSA processes running under different SRT conditions was obtained.The results showed that:(1) SBR/OSA process can reduce excess sludge production availability, and this is the result of the interaction system of each work area. They are indispensable, and this is mainly for the anaerobic digestion sludge decay, the main reaction zone sludge compensatory growth. the sludge reduction effect is best in SRT=20d and the residual sludge can be reduction of 39%. With the SRT lengthen or shorten, the sludge reduction effect of system are decreased slightly, when system sludge age for 10days, the excess sludge was reduced by 34%, when the system sludge age is 30 days, the excess sludge was reduced by 30%.(2) The sewage sludge of anaerobic digestion in the SBR/OSA process is reduced, and the part of the release organic compounds is removed by anaerobic denitrification, and this sludge through the system back into the main reaction zone is continued to use, then COD and TOC did not occur significant changes in the anaerobic digestion, but TN decreased slightly and TP increased, and the protein, polysaccharide and VFA have increased significantly.(3) The sludge age of SBR/OSA reduction system and the anaerobic sludge reflux pathway will not have a significant impact to remove nutrients in the main reaction zone, and the small reflux amount of anaerobic digested sludge was beneficial to the treatment of organic matter in the main reaction zone.To be compared with the control group, the removal rate of COD in the experimental group was 1.1%,0.6% and 0.2% Under the conditions of SRT=15d, SRT=20d and SRT=30d.(4) The results of microscopic examination and scanning electron microscope showed that the return sludge in the anaerobic digestion zone changed the micro-structure of the sludge and the microbial community. The aerobic anaerobic environment has a great influence on the micro structure of the sludge, and to be compared with the reference system, then the spatial structure of activated sludge in SBR/OSA system is more advanced, the activity of the sludge is higher, and it is beneficial to all kinds of microbial metabolism. The increase of the sludge activity and the reduction of the particle size are favorable to the attenuation of the sludge, so as to improve the effect of the sludge reduction. Compared with the control SBR system, when SRT is 15days the sludge reduction system SOUR increased by 6.8%; when SRT is 20 days, that increased by 11.5%; when SRT is 30 days, that increased by 17.4%. In the case of SBR/OSA, the mean diameter of sludge in the main reaction zone was 157μm, while that was 175μm in the main reaction zone of SBR process.(5) The initial adsorption of organic pollutants in wastewater onto the activated sludge of SBR/OSA process is fast process, which is mainly based on physical adsorption and biological adsorption.When the adsorption equilibrium was reached, the adsorption capacity of the main reaction tank’s sludge was greater than that of the anaerobic digestion reaction tank’s and the removal rate of granular COD was higher than solubility COD.The adsorption of non precipitation, particulate and dissolved COD were 139.6mg/L,100.62 mg/L and 38.94 mg/L respectively in the main reaction tank, and the sludge was 121.61 mg/L,89.7 mg/L,31.91 mg/L respectively in the anaerobic digestion tank.(6) Two kinds of sludge in SBR/OSA system are better fit Freundlich adsorption isotherm,and they are good organic adsorbents.The adsorption performance of the main reaction tank’s sludge is better than that of anaerobic tank’s sludge and The R2 of the main tank’s sludge was 0.9778, which was greater than 0.9350 of the ARS sludge.The smaller the particle size and the less the surface charge, the better initial adsorption performance of organic pollutants onto sludge. |
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