The Aerobic Biodegradation Of UDMH Wastewater And Its Kinetics Research

Unsymmetrical dimethylhydrazine (UDMH) is the main liquid rocket propellant. There are plenty of toxic and stable contaminations in its wastewater. Its harmful influence had being considered. Nowadays disposal technology of wastewater containing UDMH had plenty of disadvantages, such as high energy consuming, low safety factor, numerous secondary contamination, strong toxicity, and so on. It was necessary to find a new way for wastewater disposal. Biodegradation technology was a new sewage disposal technology, which developed quickly in recent years. This method had been adopted by mass effluent treatment plant, because it was low innocuity and cleanliness, had great degradation capacity, and can almost degrade all kinds of organic substance. In this paper the aerobic active sludge was used to treat wastewater containing UDMH which was one kind of biodegradation technology. The aerobic active sludge with big granule, good sedimentation, clearly effluent, rotifer under the microscope was acclimated for 60 days, and the removing rate of CODcr and UDMH were 89% and 98% respectively. During the acclimating process, CODcr, DO, nitrite, UDMH should be measured. It was shown that DO was the most important factor which could influence the growth of bacteria, sludge character, effluent quality. So it was indispensable to keep the appropriate DO. pH, sludge concentration, temperature and milling rate could influence biode-gradation effect. When pH was 7.0~7.5, sludge concentration was 1.6~1.28g/L, temperature was 25~30℃, and milling velocity was 80~100r/min, the degradation power was the best. According to the kinetics analyze, the aerobic biodegradation was approximatively first order reaction. Hereby the macro dynamics equations of different concentration were got. Higher the concentration was, less the velocity constant was. UMDH which had not been oxidated, FDMH, TMT, DMA, DMF, acetaldehyde dimethylhydrazone, 1-methyl-1H-1,2,4-triazole were found in the degradated water by GC/MS analyze. FDMH was a large proportion in all the compounds. According to the GC/MS graph, the aerobic biodegradation mechanism of UDMH was inferred. In a word, the method could effectively remove UDMH in liquid waste with the reaction being peaceable, running cost lowly, and it was an effective process for treatment of the UDMH wastewater.