Treatment of Wastewater from Aniline Production by H.S.B.Microorganism Bioche

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key words：H.S.B.；biochemical treatment；aniline sewage
　　Abstract：Through testing and screening the methods for the treatment of the wastewater from aniline production?a process flow of stripping-biochemical treatment was determined.The biochemical treatment used H.S.B. seeds capable of metabolizing organisms　which are hardly degradable and a UASB-SBR series process.The results of the pilot tests and of the operation of the project showed that the aniline removal rate from the aniline sewage was ＞99％ and CODcr was ＜100 mg/L.

Outline
The chemical industry limited company uses the aniline sewage which the nitrobenzene gas phase catalytic hydrogenation craft production aniline produces, the aniline density reaches as high as 30000 mg/L, the processing difficulty is big. Regarding this the water uses the stripping law, the resin adsorption law, the ultrasonic wave law, the extraction method, the carbon fiber adsorption law, the oxo-process and the chemical reaction law successively and so on carries on the processing experiment, the effect is not ideal. Latter uses the stripping - biochemistry law craft, the highly concentrated aniline sewage after the stripping recycling, then carries on biochemistry processing, the mold mushroom spawn selects introduces Taiwan's H.S.B microorganism mold mushroom spawn, in February, 1998 the aniline sewage biochemistry treating plant completed, throws transports, the installment water leakage density was lower than the national emissions standard, and in September, 1998 smoothly through Nanjing Environmental protection Bureau's approval.
1 processing craft determination
1.1 sewage water volume, water quality
The aniline uses the nitrobenzene heating carries on the hydrogenation to the gaseous state and the hydrogen under the catalyst function to make the thick aniline, again through the purification, takes off in the thick aniline the water and the high boiling point material makes the end product aniline. The sewage comes from the return to original state and the purification process, has the quantity is 0.5 m3/h, the aniline content: In front of the stripping the density is 20000~30000 mg/L, after the stripping is 1000~2000mg/L, after the exposed air the sewage becomes the brown, is one of highly concentrated organic sewage which at present domestic and foreign difficult to process.
1.2 processing craft choice
　　From 1993 to in 1997 4 years, for the choice good government method, the attack group has carried on the stripping law, the resin adsorption law, the carbon textile fiber adsorption law, the extraction method, the aniline formaldehyde condensation method, the ultrasonic wave law and the biochemistry law experiment successively,
The stripping law can process the highly concentrated sewage also can recycle in the sewage the aniline.
　　The aniline belongs to the organic matter which the difficult biochemistry to degrade, not easy direct good oxygen decomposition. The choice tires of the oxygen - good oxygen series method, may use tires of the oxygen biology to cause the aniline after the acidification and the methanation function, decomposes for the easy degradation product, except that then with the good oxygen biological treatment series, causes the pollutant.
The upper reaches -like tire of the oxygen sludge bed reactor to have the sludge prilling, the processing efficiency high, separate and so on the characteristics; In the good oxygen reactor intermittent type active sludge law has invests, the processing water quality few stable, can effectively except characteristics and so on nitrogen element, thus selects the above two kind of reactors.
1.3 mold mushroom spawns
Material [1] demonstrated that, in the aniline member the benzene ring return to original state and the break makes the medium by the leather blue negative microorganism. With in the conventional law raise sludge, basic does not include the decomposition aniline superiority mold mushroom spawn, therefore whether the choice does include the superiority mold mushroom spawn's bacteria colony is the aniline sewage obtains the effective processing key.　　The H.S.B. mold mushroom spawn is from the deep sea lake base, the chemical plant the soil and other superiority mold mushroom spawn (80 many kinds of) selects the partial mold mushroom spawns to form the specific allocated proportion, thus forms the special smooth the food chain, uses various mold mushroom spawns alternate growth differently, lives, metabolism relations, decomposes the specific organic matter, at present, the H.S.B. mold mushroom spawn researcher has grasped has the many material particle new strain, the use degradability material particle compatibility, can degrade the different organic matter the material particle to combine to a strain in, composes more than a nature new strain, like this enables one kind of microorganism to degrade many kinds of pollutant, also can complete in the degeneration process many links. Moreover also may not have the degradability material particle strain through the union shift to take to bring with the material particle, obtains the degeneration ability, constructs the super project fungus, the H.S.B. mold mushroom spawn can process on hundred complex organic matter [2], therefore designated the H.S.B. microorganism takes the mold mushroom spawn processing aniline sewage.
2 biochemistry experimental experiments
In order to confirm the sewage treatment technical process the feasibility, has carried on the scale is the 20L/h biochemistry experimental experiment.
After 2.1 experimental water used water quality (stripping)
2.2 processing flows (see Figure 1)
　　
May know by Table 4, when enters water aniline content <2000 mg/L, CODcr<7000 mg/L, the aniline elimination rate reaches 99.9%,
　　CODcr<100 mg/L, chromaticity <50 time, achieves the national level emissions standard. According to the experiment, removes 1kg CODcr to produce sludge approximately 0.05 kg.
　　The above result indicated, introduces the H.S.B mold mushroom spawn by Taiwan to have the strong resolution capability to the aniline, also the operating cost is low, operational, may apply in the production.




3.1 engineering design parameter
　　The aniline sewage treatment project enlarges 50 times in the experimental foundation to carry on the design, basic flow and experimental similar, but even more has the strain capacity and the feasibility, and increased the waste water pretreatment system, all levels of water leakage may the backflow, processing aniline sewage ability be 20~30 m3/d, the main craft controlled variable and the target are: The original water pH value 7~8, tires of the oxygen and the aeration temperature 15~45℃, original water COD≤7000 mg/L, tires of oxygen time 48 h, aeration time 20 h, stored air pressure 0.2~0.4 MPa
3.2 mold mushroom spawn domestication stage
mold mushroom spawn domestication time is 65d, 4 H.S.B. law processing aniline sewage some discussions
4.1 mold mushroom spawns throw add the way
in the project construction, tires of the complete mold mushroom spawn investment in the oxygen pond, after installment movement certain time, tired of in the oxygen pond to appear the sludge, explained the H.S.B. mold mushroom spawn had the strong compatibility, the good oxygen bacterium in tired of in the oxygen pond to be at the dormant state, but tired of the oxygen bacterium to grow gradually and combines to form the unique granulated sludge to subside mutually, is at the dormant state the good oxygen bacterium as a result of aerosol to lead in the water the oxygen pond, met the suitable environment to grow again, combines to form the cotton wool shape sludge This kind throws adds the way also to explain the anaerobe group becomes reconciled the oxygen bacteria colony besides certain superiority mold mushroom spawn, the majority of mold mushroom spawns are same. In addition, the regular supplement few mold mushroom spawns are advantageous to the system normal operation, in 1999 this sewage-treatment plant has supplemented one time.
4.2 poisons attack to the mold mushroom spawn the influence
　　The UASB system granulated sludge and the circulation installment, has to certain poison impact tolerance, but if the long time highly concentrated sewage enters the system, the mold mushroom spawn will grow comes under the suppression, and will have the possibility to form the single butcher condition to destroy the biological aggregate (pellet or cotton wool shape), moreover single butcher condition mold mushroom spawn easily along with sewage outflow.
4.3 froth questions
Debugs in biochemistry processing and moves, frequently has the phenomenon which the massive froths produce, its reason has following several kinds:
　　① As a result of C, N, the P allocated proportion unbalanced or in the water the oxygen content excessively will be high destroys the mold mushroom spawn growth balance, the excessive growth which Nocardia will plant causes the dust color and sticks the thick froth;
　　② The mold mushroom spawn causes the poison impact the cell breakage release plasma to cause the froth.
　　These two kind of situations often appear the froth to seal the pond phenomenon, must process promptly.
4.4 activated charcoal functions
　　The activated charcoal surface has certain quantity hydroxyl, the aldehyde group and the carbonyl, easily unifies into the bacterium with the bacterium the carrier. UASB tires of in the oxygen pond the pellet sludge formation not to rely on the carrier, but the activated charcoal joins is advantageous aerosol avoids the mold mushroom spawn outflow to the adsorption in the water single butcher mold mushroom spawn, moreover has certain adsorption and the cushion poison impact function to the aniline. Because drains water frequently and in operation some questions, at the right moment supplements the few activated charcoal is necessary.
4.5 sludge growth question
　　Because H.S.B. mold mushroom spawn type entire, resolution capability is strong, thus the sludge has the quantity to be very few, if after certain cycle suitable increase aeration time, uses the time delay aeration law, but also will reduce the surplus sludge to have the quantity.
Reference
　

1] ? He Yanling. The waste water tires of the oxygen biological treatment [M]. Beijing: Chinese Light industry Publishing house, 1998.
　2] ? Jin Zhigang, and so on. Pollution microbial degradation [M]. Shanghai: East China University of Science and Technology Publishing house, 1997.