Performance Test Of An Integrated MBR Equipment For Rural Sewage Treatment And Its Sludge Reduction Potential

This article uses rural sewage to carry out a three-month production test of the integrated MBR equipment（200m³/d）,Q=8.3 m³/h,oxygen-deficient area HRT=2.4h,aerobic area HRT=7.3 h,gas water ratio 30:1,The reflux ratio of the mixture was300%,andfocus on the indicators of COD,NH₃-N,TN,TP,etc.After the test,the cleaning of the membrane assembly was carried out and the results of membrane cleaning were evaluated.The conclusions were as follows:（1）In the flooding COD was 258.5 mg/L,NH₃-N was 16.59 mg/L,TN was25.40 mg/L,TP was 1.97 mg/L.After treatment of the integrated MBR package,effluent COD was 37.2 mg/L,NH₃-N was 3.32 mg/L,TN was 12.00 mg/L,TP was1.09 mg/L,with removal rates of 84,79,52,43%.The effluent COD,NH₃-N and TN could meet the first class A standard in the Municipal Sewage Treatment Plant Pollution Release Standards（GB18918-2002）,and TP was not able to meet the standard.（2）Cleaning the membrane module by on-line chemical cleaning,configuring0.3%sodium hypochlorite solution and 0.5%oxalic acid solution,each film 3 L,the membrane pressure difference before cleaning was 54 k Pa.After cleaning,the mixture of activated sludge was filtered,the transmembrane pressure difference was43 kPa,which had little difference from the initial pressure difference of 40 kPa,and the cleaning effect was good.The operation cost of integrated MBR complete sets of equipment is calculated,and the cost of processing tons of water was 1.46 yuan.The sludge emission reduction of A/O-MBR and A²O-MBR processes is theoretically studied,the calculation formula for sludge emission is derived,the influence of different factors is analyzed,and the potential for sludge emission reduction is discussed.The conclusions were as follows:（3）For A/O-MBR process,the total HRT remains unchanged,and sludge emissions increased with the increase of HRT in oxygen-deficient areas;in the oxygen-deficient area,HRT remained unchanged,and sludge emissions decreased with the increased of total HRT;the aerobic zone HRT remained unchanged,and sludge emissions increased with the increase of the total HRT;the sludge discharge increased linearly with the increase of r,when the mixture reflux ratio r>1;the larger the SRT,the less sludge emissions.（4）In the A²O-MBR process,the total HRT was constant,the HRT in the anaerobic zone was unchanged,and the sludge emission increasesd with the increase of HRT in the anoxic zone;the total HRT and the HRT in the anoxic zone was unchanged,and the sludge emissions were dissipated the increase of HRT in the oxygen zone increases;the sludge discharge increased with the increase of sludge r and R;when the SRT increased,the sludge discharge decreased.（5）Influent COD 250,500,1000 mg/L,effluent COD 50 mg/L,compared with the traditional A/O process,the sludge abatement potential of A/O-MBR was 75,86,88%.Compared with the traditional A²O process,the sludge abatement potential of A²O-MBR was 73,83,85%.