Study On Applying Biofilm-membrane Biological Reactor In Treating Micro-polluted Water

In this paper, application of membrane technology and cell immobilization technique for treatment of micro-polluted source water was studied. As a result, conventional technological progress of drinking water treatment was simplified and the efficiency was improved. Integrating the characteristics of progress in biofilm system and in membrane bio-reactor, the biofilm-membrane bio-reactor (BMBR) technique was proposed. In the reactor, the biofilm adhered and grew on the fiber film and then the double film was formed with the properties of degradation and separation. Application BMBR progress for drinking water treatment has not been reported. In order to testing the feasibility in applying this technology in drinking water treatment, this paper designed a laboratory scale BMBR and studied on the mechanism and the optimum operating condition.Firstly, during the BMBR progress for drinking water treatment, we found the best HRT was 0.8 h to improve the removal of the pollution by determining removal results of the organic compounds, ammonia nitrogen compounds.Secondly, by analyzing organic molecular weight distribution, the result, in which both high molecular weight organics (>10K) and low molecular weight organics (<3K) were dominant and had a much large occupation in the mixture solution of the reactor, indicated the intensified interception of organic substances by the biofilm attached membrane. By jar testing, the removal effect of COD and ammonia nitrogen was observed to study the biofilm of adhering to membrane. Simultaneously the quantity of biomass of membrane indicated the intensified removal efficiency of contamination by the biofilm.Lastly, we analyzed the reason of the membrane fouling is that filtration resistances would be determined by fouling mainly composed of pore blocking and gel layer formation. The main composition of gel layer adhered to the surface of membrane was extracelluar polymers (EPS) produced from germ. The extent of membrane fouling was depended on the length and the condition of operation.During the whole operation of the reacter, average turbidity removal efficiency was 95.0%, with average permeate of 0.2NTU. While average ammonia nitrogen removal efficiency was 78.6%, with average permeate of 0.38 mg·L-1. And average removal efficiency of CODMn, UV254 and THMsv were 76.2%, 50.1% and 70.7%, with average permeate of 2.39 mg·L-1, 0.036 and 0.3μg·L-1, respectively. The overall...