Research On The Purification Of VOCs By Biofiltration

Biofiltration is rarely researched at present, especially the application of the filter and effect with the selection and properties of packing. The major objectives of this work were to seek suitable biological packing material for biofiltration treatment of formaldehyde and benzene, and to explore a convenient and effective of reactor. The physical properties of ordinary soil and mixed material were tested in this work, and the removal efficiencies of formaldehyde in biofilter packed with ordinary soil and mixed material separately were compared. Furthermore, the removal efficiencies of formaldehyde and benzene with packing thickness, water content of packing material and spider plant root were investigated in this paper. The main conclusions are as follows:(1) The water content, total organic content and permeabilities of two different packing were compared in this work, we found that the mixture of organic soil,vermiculite and ceramic hybrid materials were better than normal soil. Under the same operation and formaldehyde inlet concentration, the formaldehyde purification efficiency of mixture material was also higher than normal soil.(2) In this experiment, we choose the mixture material as biolofilter packing. The formaldehyde purification efficiency and purification rate with different packing thickness were compared. At the experimental concentration range, the formaldehyde purification efficiency with 5cm packing was smallest, and purification efficiencies with 10cm,20cm packing were more than 90%, the formaldehyde purification efficiency with 10cm packing was the largest during this experiment which means purification ability of 10cm was better and the microbial biomass contents was enough. The formaldehyde purification efficiency increase with packing water content at the experimental concentration range, increase in the water content can increase the formaldehyde purification ability of biolofilter. The effect of formaldehyde purification efficiency by spider plant root was studied, and the results showed that the formaldehyde purification efficiency with tips of plant root was the best. When the formaldehyde inlet concentration was lower than 0.3g/m3, the formaldehyde purification efficiency of biofilter with 10cm packing was more than 98%, the formaldehyde outlet concentration was less than 0.03 g/m3 and meet national standards.(3) Choosing the mixture material as biolofilter packing in this study, packing thickness had great effects on benzene purification efficiency of biolofilter with spider plant and without spider plant. The benzene purification efficiency with biomass content of 10cm packing material was better at low benzene inlet concentration. And the benzene purification efficiency with biomass content of 20cm packing material was better at high benzene inlet concentration. The effect of benzene purification efficiency by spider plant root was studied, the results showed there is no different and the benzene purification efficiency were 100% steadily with 30cm packing thickness at spider plant experiment and no spider plant experiment when the benzene inlet concentration was low. But when benzene inlet concentration was high, benzene purification efficiency with 30cm packing thickness at spider plant experiment was higher than no spider plant. At the spider plant experiment, the benzene waste gas can be purified completely by biolofilter with 20cm and 30cm packing and reach national standard when the benzene inlet concentration was lower than 2.72g/m3. At no spider plant experiment, the benzene waste gas can be purified completely by biolofilter with 20cm and 30cm packing and reach national standard when the benzene inlet concentration was lower than 1.27g/m3.