Research Of Anaerobic-MBR System In Wastewater Treatment And Mathmatical Model

Wastewater anaerobic treatment has drawn increasing attention,and such treatment plants also have been applicated in full-capacity wastewater treatment plants.The anaerobic membrane reactors are the conbination of the anaerobic reator and membrane technology,whihc is a promising method for high concentration organic polluants wastewater treatment and emphasizing research of many organizations,such as Water Environmental Research Foundation.Anaerobic membrane reators have great pratical potentials of enerngy recovering and excellent effluent quality.Using anaerobic membrane reator treated high concentration organic polluants synthetic wastewater.The resul tshows that two anaerobic membrane bioreactor is feasible for pratical using.During the start-up,the COD of the liquid supernatant was stable between 600-700 mg/L,and biological efficiency was stable in 77%,physical efficiency raised from 2.1% to 19.5%.The VFA concentration in the reactor gradually increased,which means occurance of acetogenic bacteria.Other volatile acid concentration has no obivious change.MLSS increased from 16.5 mg/L to 24.8 mg/L,MLVSS increased 12.4 g/L to 19.7 mg/L,MLVSS/MLSS also increased to 0.79.The influent COD gradually increased from 3000 mg/L to 4000 mg/L duiring stable ruunig period,the total COD removal rate exceeded 90%,showing the good removal efficiency.MLSS and MLVSS concentration continued to increase,avearage values were 31g/L and 27.4 g/L,respectively.While MLSS and MLVSS concentration in the sludge attached membrane surface increased maximum and then decreased,and the average value of MLVSS/MLSS was 0.77.During stable running period,VFA concentration increased maximum and then decreased,which indicateds Methanogenus in the reactor began to decompose the accumulated VFA.During this period,it showed the stable producation of biogas.Effluent COD was constantly lower than 300 mg/L and total removal efficiency reached 97% when HRT are at 48 h?36 h?24 h or 18 h.While HRT was cut to 12 h,effluent COD concentration increased and total removal efficiency gradually decreased where the minimum value was 77.3%.When HRT ranged from 48 h to 24 h,formic acid,acetic acid,propionic acid and butyric acid concentration didn't change very much.VFA content was stable at low value.But when HRT was cut to 12 h,the system operation efficiency began to decrease.During the most time of load enhancing period,production and the methane content of biogas maintained a high level,and also when HRT was cut to 12 h,production and the methane content of biogas dramatically decreased.When influent COD increased to 8000 mg/L and HRT at 48 h,36 h and 24 h,effluent COD was contantly lower than 300 mg/L and total COD removal efficiency was 97.4%,but when HRT was cut to 18 h,the biological COD removal efficiency decreased to 70.8%.When influent COD was 12000 mg/L,the optimal HRT should controlled at 36 h.When influent COD was 15000 mg/L or 18000 mg/L,the optimal HRT should controlled at 48 h.When influent COD was higher than 20000mg/L,effluent quality deteriorated,reactor operation decreased.Based on anaerobic digestion model,a mathmatical model for anaerobic membrane bioreactor was established.Then parameter sensitivity analysis was conducted,especially those paremeters assisociated with VFA content and COD,considering the poor simulation in acetic acid of the preliminary model.After,Y_ac,ks_ac and km_ac were adjusted.A perfect results of effluent water quantity simulation was achieved after the adjustment and correction of parameter of ADM1 model.And also some inner structure of the model was found and reflceted s anaerobic digestion in the reactor.