生物膜填料塔净化含甲醛异味气体的研究

Research on purification of formaldehyde waste gas in biotrickling filter

采用改进的排泥挂膜方式进行微生物挂膜,扫描电子显微镜观察生物膜表面生物形态,探讨进气速度、停留时间、液体喷淋量、容积负荷等主要因素对不同浓度甲醛气体去除效率的影响。结果表明,驯化30 d脱除甲醛的生物膜已基本成熟,生物膜表面长有大量真菌丝、原生及后生动物;优势菌体形态为球状和杆状,其中球菌直径2～2.5μm,且为中空网状的多孔性球团。通过对生物膜填料塔净化效果的研究,得到最佳工艺参数。当甲醛质量浓度为10～40 mg/m^3,停留时间为27 s,液体喷淋量20～40 L/h,容积负荷1～7.5g/(m^3·h)时,生物膜填料塔对甲醛的去除效率达到94%以上。

Because of its superiority on elimination of formaldehyde, biotrickling filter has become a hotspot of research at home and abroad. The effects of four important operation parameters which are gas doneentration, retention time, liquid spray volume and volume load on the biodegradation of formaldehyde in a gas-phase biotrickling filter were studied. The experimental results showed that the biofilms have been maturally domesticated by 30 days. There were various types of true mycelium, protozoa and metazoa on the surface of biofilms. The dominant cell morphologies were coccus, filamentous fungus and rod-shaped bacteria. The diameter of coccus and hollow porous mesh pellets were 2 - 2.5 ktm. The optimum process condi- tions were obtained through studying the formaldehyde removal effi- ciency of biotrickling filter. When the concentration of formaldehyde varied between 10 - 40 mg/ms, the retention efficiency of biotrickling filter was higher. When the concentration of formaldehyde was 28 mg/m3, the removal efficiency of biotrickling filter tower could be maintained above 94 %. In the biological purification process, the re- moral efficiency increased with the increase of residence time. When the residence time varied from 10.8 s to 27 s, the removal efficiency increased from 89.7% to 94.56% . With the increase of liquid spray volume, the removal efficiency of biotrickling filter was enhanced. When the amount of liquid spray was risen from 20 L/h to 40 L/h, the removal efficiency improved from 86 % to about 94 % . When the purification system volume load of formaldehyde was 1 - 7.5 g/（m3·h）, more than 90% of the hazardous compound can be re- moved. On the other hand, when the volume load was greater than 9 g formaldehyde/（ m3·h）, the formaldehyde removal efficiency de- creased following the increase of load volume.