| Since recycling reclaimed water has become the most practical way in dueling with water shortage, to study and develop its technology is being more and more important today. Combining the functions of degrading pollutants and separating sludge from water, submerged membrane bioreactor (SMBR) is now an ideal technology in achieving reclaimed water reuse. Because of its relative low polutants concentration and simple component, sanitary waste is a suitable source for reclaimed water reuse.The surfactant in sanitary water is hard to biodegrade, and the foam caused by surfactant can lead to the decrease of the reoxygenate rate which will hinder the process of sulf-purification of water body.The thesis is based on such a background and focuses on the study of the SMBR technology in the field of reclaimed water reuse and the removal characteristics of surfactant.Experimental results show:When HRT was above 5h and volume loading of linear alkylbenzene sulfonate (LAS) was between (0. 0060. 12) kgLAS/(m3·d), the LAS removal efficiency can be high and stable which reached 85%99.5% and the effluent concentration was less than 1.0mgLAS/L which meets the demand of "water-quality standard of sanitary miscellaneous water" (CJ25.1-89). And the changes in volume loading and sludge loading had little effect on the LAS removal efficiency. And when volume loading was between (1.03.6)kgCOD/(m3·d) at the HRT of 4h to 6h, the MBR can remove COD by more than 90% which showed that the COD removal efficiency was less affected by volume loading and HRT. But on the other hand, ammonia-N removal efficiency was subject to the volume loading. The removal efficiency dropped from 92% to 30%70% while the volume loading increased from 0.12kgNH4+-N/(m3·d) to 0. 23kgNH4+-N/(m3·d).And while the gas water ratio ranged from 20:1 to 60:1, the removal efficiencies of LAS,COD and NH4+-N were 80.1% 87.5%,95.2% 98.5% and 13.9% 96.9% respectively. These indicated that gas water ratio affects LAS and COD removal efficiency little but affects NH4+-N removal efficiency in some degree. In addition, the sludge was aging and in small broken bits when gas water ratio reached 60:1 which led to the increase of the total fouling resistance. During the running process, the membrane flux decline velocity increased while the gas water ratio decreased. To consider comprehensively, the system will run more efficiently when gas water ratio is between 40:1 and 50:1.The sludge characteristics in the reactor were also studied. Sludge concentration in stable stage increased with the enlargement of volume loading and the maximum concentration attained 15.6g/L.During the running process, SV30 remained above 90% which indicated the poor settle ability of the sludge, at the same time VSS/SS stayed high and stable with the average of 0.89. In the study of membrane fouling mechanisms, cake layer had been found to be the controlling factor in the filtrate process. The cake resistance which is composed of polarization layer resistance and external fouling resistance contributed more than 75% value to the total fouling resistance in the distribution tests of resistance. And the specific cake resistance of sludge grew with the SRT while was unaffected to HRT.In the study, several methods were used to recover the membrane flux. The effects of physic membrane washing were limited compared with the chemical membrane washing. The increases of the recovery of membrane flux by hydraulic washing, mechanical shake and air backwashing were 16.8%20.7%,8.8%27% and 9.28%-— 12.8% respectively. In the chemical washing, the washing order of "hydraulic washing + alkali washing + acid washing + oxidant washing (NaCIO)" obtained the best effect which membrane flux recovered to 98.6% value of the original flux and the increase of the recovery of membrane flux attained 82.5%.
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