Submerged Membrane Bioreactor For Domestic Wastewater Treatment

Integrated membrane-bioreactor is adopted in this paper to treat domestic wastewater. Across the long system of operation phase, running time is 30d,pumping water yield is 24mL/min and aeration rate is 0.1m3/h. After 10min of pumping there comes 2min of pause, then the treatment efficiency turns out to be rather high among the indexes of COD, TOC, NH₄⁺-N, which are respectively achieve 93.4%, 96.2%, 97.2%. The lower removal rates of TN, TP respectively are 63.8%, 60.6%, but also the overall performance to resist impact load is increasingly high with the higher sludge concentration. The theoretical sludge yield coefficient Y has been figured out to be 0.377mgVSS/mgCOD based on sludge proliferation kinetics theory, and the attenuation coefficient Kd is 0.086d^-1. The degradation rate K of simulated domestic wastewater ranges from 0.002 d^-1 to 0.0045 d^-1, and the average value is 0.0027 d^-1 which is figured out abased on organic pollutants degradation kinetics.Across the orthogonal experiment phase, impact of operation condition on the degradation rate of COD in supernatant are ranged as following: pumping water yield > pumping time > pause time > aeration intensity, and on membrane aspiration pressure growth rate are ranged as following: pumping water yield > pause time > pumping time > aeration intensity.The specific flux of membrane can be recovered through the interaction among hydrodynamic cleaning and chemical washing and ethanol immersion. After infrared spectrum analysis about pollutants on the surface of membrane and scanning electron microscope analysis about both new membrane and the polluted, the resistance from sludge cake layer account for 89.86% of membrane filtration total resistance, turning out to be the main components of membrane pollution.