Studies On The Bio-degradation And Treatment Techniques Of Industrial Wastewater Containing Nitrobenzene Compounds

Nitrobenzene compounds, as the direct or indirect synthetic raw materials of many industries such as dyestuff, medicine, pesticide, explosive and so on, are of great importance in the whole organic chemical industry. Nitrobenzene compounds are stable, hard-to-degrade and can do great harm to environment. The wastewater discarded during the production still contains intermediate products and inorganic salts, which makes the treatment of this kind of wastewater even more difficult. To solve this problem completely, this paper, using the real industrial wastewater as experimental material, has taken shock loading caused by some organic pollutants and inorganic salts into full consideration and systematically studied biodegradability improvement of the wastewater, characteristics of halophilic compound bacteria group and parameters of bio-augmentative treatment. Main experimental results are as follows:1. As far as the complicated nitrobenzene compounds production wastewater is concerned, to adopt pretreatment process is essential and feasible. Using the ferric sulfate as flocculate agent and caustic lime as auxiliary flocculate agent can achieve good results.2. All the three kinds of pretreatment, i.e. Fe2+/ Fe3+ reduction oxidation system, Fenton agent system and electric chemistry reduction system, can improve the biodegradability of nitrobenzene compounds production wastewater obviously. However, when fully considering the costs of treatment, investment of equipments and convenience of operation, the electric chemistry reduction system is preferable one.3. The facultative anaerobic hydrolysis technique is effective in treating nitrobenzene production wastewater. The facultative anaerobic bacteria cultivated can turn nitrobenzene into aniline, and in turn further improve the biodegradability of the wastewater, which provides favorable conditions for the following aerobic treatment process.4. The bacteria cultivated for the treatment of nitrobenzene production wastewater can degrade not only nitrobenzene but also some other organic pollutants through biological cooperative effect on condition that the salt degree is below 15000 mg/L. The contrast experiment shows that, when applied to the treatment of the hard-to-degrade industrial wastewater, the Power Active Carbon Treatment (PACT) is superior to thetraditional techniques on anti-shock loading, removal ratio of CODcr and etc. The effective combination of PACT with the halophilic bacteria for nitrobenzene production wastewater may be the best aerobic bio-treatment way to treat this kind of wastewater now.5. The organic combination and application of electric chemical reduction pretreatment, facultative anaerobic hydrolysis technique bacteria for nitrobenzene production wastewater and PACT to the treatment of this kind of wastewater have produce very good results. The removal ratio of CODcr, nitrobenzene(NB) and chromaticity color are above 85.1%,98.7% with 95.9% respectively.In a word, extensive and intensive study on improvement of biodegradability, cultivation of efficient bacteria and techniques of bio-augmentative treatment has been conducted in this paper. The results gained and analysis carried will have important theoretical significance, guidable use and applied value on effective treatment of nitrobenzene production wastewater and other similar wastewater containing hard-to-degrade organic pollutants.