Study On Zero Valent Iron And Magnetism On Anaerobic Biodegradation Of Nitrobenzene

At present,there are many report of Fe0/microbial degrade organism from scholar of domestic and international. But the demerit of the treatment system is that ferrous powder is prone to sink to bottom, so magnet was assumed to add into the treatment system of Fe0/microbial, this can make the ferrous powder adsorbed onto the magnet's surface. This can augment the contact area between ferrous powder and anaerobic sludge, making the efficiency of ferrous powder accelerated; in addition, this also can let the magnet prone to control, making replace and cleanout ferrous powder easier and solve the demerit of aggradations. But there is no reported treatment system of Fe0/magnetism/microbial. This experiment make nitrobenzene(NB) as object matter, try to explore the treatment system's degradation effects, factors and mechanism.In this paper, The start-up of UASB reactor treating simulated wastewater was studied, in this process, change of pH, TSS, VSS, CODcr and CODf of the UASB reactor's yielding water was studied , CODf removal rate of each part of UASB reactor was delved ,and the causation was aslo explored, so as to provide a reference for start-up of UASB reactor.Based on successful start-up of the UASB reactor, granular sludge in the UASB reactor was used for experiment, NB was the target pollutants. Treatment system of Fe0, magnetism, microbial, Fe0-microbial, Fe0-magnetism, magnetism-microbial, Fe0–magnetism - microbial and blank control were detected. In the three substance of Fe0, magnetism and microbial, if there is synergistic effect or inhibiting effect between the two of them to degrade nitrobenzene was delved, influence factor of zero valent iron/magnetism/anaerobic was researched, at the same time, quantity of ferrous ion, ferric iron and aniline was also delved, on these bases, the degradation mechanism of treatment system of zero valent iron/magnetism/anaerobic was studied, the results presents as follows:(1) UASB reactor can be start—up successfully by the three stage measure in this paper, fast and efficiently .After start-up, CODcr removal rate and CODf removal rate of the UASB reactor could reach 75%, COD removal rate is UASB reactor's yielding water> upside of UASB reactor> middle of UASB reactor, amplitude of fluctuation of COD removal rate is middle of UASB reactor> upside of UASB reactor > UASB reactor's yielding water.(2) There is no evident inhibiting effect after magnetism add into treatment system of zero valent iron/anaerobic, treatment system of zero valent iron/magnetism/ anaerobic can fasten ferrous powder by permanent magnet, make the ferrous powder hang in the biochemical aeration tank. By doing this will not only broaden contact area between ferrous powder and anaerobic sludge, but also replacing and cleaning ferrous powder by controlling the magnet, which can settle the problem of aggradations and have a certain production value of industrialization.(3) Quantity of Fe0 of 240 mg/L is the best choice; NB removal rate can reach 98% in 120h. The best magnetic field strength of treatment system is 6mT, at this magnetic field strength; treatment system can reach its best activation.(4) After add zero valent iron and magnetism together, the most suitable temperature range of anaerobic sludge changed from 30℃-35℃to 35℃-40℃.