Experimental Study On Trickling Biofilter System For Purification Of Volatile Organic Compounds (VOCs)

With the development of society, people increasingly hope to acquire a further well survival surrounding, and pay more attention to the environmental pollution problem, such as air pollution. The recovery of low concentration VOC waste gas is valueless and its treatment is very difficult and expensive for traditional physical and chemical treatment technologies. The biological treatment technology of VOC waste gas has become a research hotspot in the world because of high purification efficiency, low charge of investment and run, and no secondary pollution etc. Up to now, many practical installations have been used in the West Europe, while there are only a few reports about its application in our country. In this work, the study on performance of a trough distributor and a perforated plate distributor for trickling biofilter is conducted. Then the microorganism is cultivated and domesticated. The start-up of trickling biofilter with ceramic sphere and the purifying performance for xylene waste gas are also studied primarily. Finally aiming at the exhaust of waste gas from paints manufacture work in Chongqing xianxia paints Co. Ltd., a pilot system of the trickling biofilter is designed and made firstly and then the two-phase flow friction characteristic and the start-up of trickling biofilter are studied in the pilot field. The remarkably conclusions are drawn as follows: 1,From the performance test of the trough distributor and the perforated plate distributor, The effects of liquid flow rate, inclination of liquid distributor, and structure of liquid inlet on the liquid malddistribution coefficient were discussed, respectively. The experimental results show that the distributing performance of perforated plate distributor is generally better than that of trough distributor. The trough distributor is applicable to the trickling biofilter for lower liquid flow rate. 2,A kind of strain that could effectually degrade toluene and xylene is obtained through five-period domestication. Constituents of culture medium and the best growth conditions of this kind of the strain are studied, which lay solid foundation for future works. 3,Through the experiments on the start-up of trickling biofilter with ceramic sphere and purification efficiency for xylene waste gas, it is found that the development profiles of OD and pH of recurrent liquid, pressure drop of packing media bed and xylene concentration of inlet during the start-up of trickling biofilter have a great effect on the biofilm formation. In this experiment, the purification efficiency of trickling biofilter dropped with the increase of gas flux , liquid flux and xylene concentration of the inlet obviously. 4,Based the two-phase flow friction characteristic and the start-up of trickling biofilter on the pilot system which set in Chongqing xianxia paints Co. Ltd., it is found that as the flow rate of gas and liquid increase, the flow resistance of gas increases, and especially after startup. The results of the start-up of pilot system reveal that toluene and xylene are reduced partially, however the purifying performance is lower than that of the laboratory experiment because of the conditions such as contamination concentration of waste gas, temperature of operation, maldistribution of the liquid distributor and activation of the strain representatively.