The Application Of Submerged Anaerobic Membrane Bioreactor Treating Domestic Wastewater

Anaerobic membrane bioreactor combines the advantages of membrane filtrationtechnology and biological treatment technologies. It has many advantages, such as smalloccupied area, low power consumption, producing methane gas, small sludge yield andeasy to treat, HRT and SRT can be separated completely. It solve many problems thatordinary anaerobic reactors can’t deal with. For example sludge can be losen easily, it’svery dfficult to keep long generation cycles of methanogens in the reactors. Thus thiskind of technology attracts the attention of scholars at home and abroad. However,research mainly focus on the application of anaerobic reactor treating highconcentration organic wastewater in high temperature conditions at the present stage,few scholars study applying anaerobic membrane bioreactor to treat low concentrationwastewater at low temperatures. It limits the development and application of anaerobicmembrane bioreactor greatly.In order to expand the application scope of anaerobic membrane bioreactor. Thispaper apply submerged anaerobic membrane bioreactor (AnMBR) to treat simulatedmunicipal wastewater, study the treatment effect of AnMBR on wastewater at25℃and35℃, characteristics of membrane fouling. On this basis, exploring the effect ofaddition of granular activated carbon (GAC) on AnMBR, mainly removal efficiency andsludge properties. Two reactors operated for168days, obtained the following results:(1) AnMBR can achieve good removal effect of organics at25℃and35℃. It iscapable of long-term stable operation, with the advantages of short start time and highremoval efficiency of organic matters. During the reactor operation for168days, HRThas been maintained at1d. Influent was simulated domestic wastewater, concentrationof COD was in the range of383~728mg/L. Average removal rate of COD of anaerobicmembrane bioreactor at35℃was90%. In the condition of25℃average removal rateof COD was77.1%. The removal effect of anaerobic microbial accounted for69.4%,50%. Membrane interception can remove20.6%,27.1%COD respectively.(2)Both of the two anaerobic membrane bioreactors did not appear acidaccumulation phenomenon. Concentration of VFA in supernatant and effluent ofAnMBR1was214.7mg/L and61.4mg/L respectively. Concentration of VFA insupernatant and effluent of AnMBR2was249.0mg/L and91.0mg/L respectively. Theaverage concentration of VFA of AnMBR1was lower than that of AnMBR2. The concentration of VFA in two reactors showed the same changing trend: both decreasedgradully with the running time.(3) Taking full account of the prevention of membrane fouling of the membranemodule during designing reactor. Optimizing the layout of membrane module andstructure of the reactor to control membrane fouling in front. During the wholeoperation cycle, membrane fouling of two reactor membrane pollution were slight.Membrane module didn’t need to be cleaned. It proves that two reactors have goodmembrane pollution resistance performance. Later stage of reactors operation, thetransmembrane pressure of AnMBR1was2.0kPa. The transmembrane pressure ofAnMBR2was2.8kPa. The membrane fouling rate of AnMBR1was slower than that ofAnMBR2. At the same time, sludge properties of AnMBR1was better than that ofAnMBR2.(4) Adding granular activated carbon (GAC) can enhance the removal efficiency oforganic matter. Before adding granular into the reactors, insuring the optimalconcentration of GAC is necessary. Through experiments it can be found that whenGAC concentration was800mg/L, removal efficiency of COD was highest, while theaddition of GAC can improve sludge properties significantly.