Kanekar S P, Kanekar P P, Sarnaik S S, Gujrathi N P, Shede P N, Kedargol M R, Reardon K F
Microbial Sciences Division, Agharkar Research Institute, G.G.Agarkar Road, Pune, 411004, Maharashtra, India.
J Ind Microbiol Biotechnol. 2009 Feb;36(2):253-60. doi: 10.1007/s10295-008-0493-8. Epub 2008 Nov 1.
Nitroexplosives are essential for security and defense of the nation and hence their production continues. Their residues and transformed products, released in the environment are toxic to both terrestrial and aquatic life. This necessitates remediation of wastewaters containing such hazardous chemicals to reduce threat to human health and environment. Bioremediation technologies using microorganisms become the present day choice. High Melting Explosive (HMX) is one of the nitroexplosives produced by nitration of hexamine using ammonium nitrate and acetic anhydride and hence the wastewater bears high concentration of nitrate and acetate. The present investigation describes potential of a soil isolate of yeast Pichia sydowiorum MCM Y-3, for remediation of HMX wastewater in fixed film bioreactor (FFBR). The flask culture studies showed appreciable growth of the organism in HMX wastewater under shake culture condition within 5-6 days of incubation at ambient temperature (28 +/- 2 degrees C). The FFBR process operated in both batch and continuous mode, with Hydraulic Retention Time (HRT) of 1 week resulted in 50-55% removal in nitrate, 70-88% in acetate, 50-66% in COD, and 28-50% in HMX content. Continuous operation of the reactor showed better removal of nitrate as compared to that in the batch operation, while removal of acetate and COD was comparable in both the modes of operation of the reactor. Insertion of baffles in the reactor increased efficiency of the reactor. Thus, FFBR developed with baffles and operated in continuous mode will be beneficial for bioremediation of high nitrate and acetate containing wastewater using the culture of P. sydowiorum.
硝基炸药对国家安全和国防至关重要，因此其生产仍在继续。它们在环境中释放的残留物和转化产物对陆地和水生生物均有毒害。这就需要对含有此类有害化学物质的废水进行修复，以减少对人类健康和环境的威胁。利用微生物的生物修复技术成为当今的选择。高熔点炸药（HMX）是通过用硝酸铵和乙酸酐对六亚甲基四胺进行硝化生产的硝基炸药之一，因此废水含有高浓度的硝酸盐和乙酸盐。本研究描述了土壤分离酵母毕赤酵母MCM Y - 3在固定膜生物反应器（FFBR）中修复HMX废水的潜力。摇瓶培养研究表明，在环境温度（28±2℃）下培养5 - 6天，该菌株在摇瓶培养条件下于HMX废水中有明显生长。FFBR工艺以间歇和连续模式运行，水力停留时间（HRT）为1周，硝酸盐去除率达50 - 55%，乙酸盐去除率达70 - 88%，化学需氧量（COD）去除率达50 - 66%，HMX含量去除率达28 - 50%。与间歇运行相比，反应器的连续运行显示出更好的硝酸盐去除效果，而乙酸盐和COD的去除在两种运行模式下相当。在反应器中插入挡板提高了反应器的效率。因此，带有挡板并以连续模式运行的FFBR将有利于利用毕赤酵母培养物对含高硝酸盐和乙酸盐的废水进行生物修复。
