| The rapid development of industrialization has brought organic pollution of global water environment and total wastewater discharge in China increases every year. Industrial wastewater is the main source of environmental pollution, especially organic industrial wastewater which is harmful to the environment because of its large quantity, wide distribution and toxic substances existence.A pilot self-designed anaerobic membrane bioreactor (AnMBR) was adopted to treat acetone and isopropyl alcohol mixed wastewater in order to provide reference and guidance for promoting the engineering application of the reactor to treat high concentration organic wastewater. The control conditions of the successful startup of the reactor and optimum operating parameters were determined through the experiment for stable operation. Anaerobic gas production and its component and the particle size distribution of sludge were measured. Study on membrane module pollution was carried out. The physical characteristics of the membrane module was observation by means of scanning electron microscopy (SEM) to compare the changes in the appearance of polluted and cleaned membrane module. The methanogens abundance in different periods of AnMBR was studied with FISH techniques in order to carry out more micro and effective research.The control of temperature and organic load was the key to start the reactor. If the start temperature was too low, we could heat appropriately to make the temperature20℃. The appropriate start organic load was2～3kgCODcr/(m3·d) and the increase was slow. It took79days to start the reactor successfully at normal temperature (12.2℃～23.9℃). The organic load reached5.30kg CODcr/(m3·d), total CODcr removal rate was96.74%and the membrane effluent CODcr concentration was about1000mg/L.Based on the analysis of hydraulic retention time, organic loading and sludge concentration on the operation effect of the reactor and stable operation situation of the reactor for20days, the process parameters of stable operation of the reactor were: temperature30℃, influent CODcr concentration36000mg/L～38000mg/L, HRT60h, organic load15kgCODcr/(m3·d) and MLSS35000mg/L～37000mg/L.The CODcr removal effect was good and total CODcr removal rate between was96.89%～96.89%(98.13%average) during the stable operation stage. Influent pH was7.5～7.7, mixture pH was6.74～7.13, membrane effluent pH was6.84～7.25, mixture alkalinity was1212mg/L～1741.74mg/L, the average mixture VFA was139.97mg/L and average membrane effluent VFA was100.53mg/L. The reactor operated well. MLSS was35000mg/L～37000mg/L and the average MLVSS/MLSS was0.8949.The particle size distribution of sludge was between4～30μm. Dispersive and finely-divided sludge was obtained because of water circulation and biogas agitation. Compared with other anaerobic reactor for treating similar wastewater, it was found that this reactor took an advantage in treating similar wastewater. It was proved that intermittent effluent could help alleviate the membrane fouling compared with continuous effluent through monitoring transmembrane pressure and membrane cleaning situations. The main role of organic removal was biochemical and membrane rejection (4.13%average) of organic was only play the role of improving and stabilization.Carrying on the orthogonal experiment for FISH test conditions, it was found that refrigerated time4h, the sludge sample volume1μL and hybridization time2h wasoptimum conditions for FISH. Changes of the methanogens abundance could indirectly reacted reactor operation situation. Temperature made a great impact on methanogens abundance, which could reach0.6497during stable operation stage. |
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