Pilot-Scale Study On Urban Runoff Treatment Using Biological Filter

At present, urban runoff caused serious non-point source pollution in China. It is hard to control because of the decentralization and randomness of pollutant source, lots of influencing factors, variety of contaminations and concentrations. Nowadays many centralized treatment is widely utilized for treat storm water, which should bring the cross contamination of runoffs in different components and concentrations and have disadvantageous to sustainable development. In this paper, experiments and analyses were made to find out a distributed runoff treat technique which is simple, convenient and coincident to ecological request of city.In this paper, there are analyses of on site sample of road runoff in different seasons and different rainfall frequency in campus of ChongQing University and at commercial zone. Then biological filter(BF) have been designed and it's purification ability to urban runoff is studied. The experiment mainly include: Start-up characteristic, clarifying capacity, running characteristic and service cycle of BF.○1 When water temperature is between 15~20℃, well start-up of BF can be achieved through adoption of slight contaminated water and intermittent inflow. It is needed to enlarge the inflow period and surface loading of gradually. After the start-up, CODcr and SS removal rate of system was stabilized at level about 60%.○2 Diluted domestic sewage is adopted as inflow of the BF in experiments to study it's purification ability to slight contaminated water. Experiments in different 25 operating conditions were being carried out bases variety of surface loading, water temperature, filter material and the format of filter bed. The results shows that among the influencing factors of system removal ability, surface loading plays the key role, water temperature and filling format is in second place and affection of filter material is the least.○3 In operating characteristic test, the BF influent is roof covering and drive training area runoff during four rainfalls. The test purpose is to study the operating characteristic and to find out the problems of BF to treat actual rainfall. The max surface loading in experiment is 4.3 m3/m2·d. Double layered enzymatic filler were adopted and the average water temperature is 24.9℃. Results show that the outflow can up to the china criterions of (GB/T18921—2002) and