The Study Of The High Salt Dyestuff Wastewater Processing Technique

The dyestuff wastewater is a kind of high density, high color degree, low pH value, and one of the organic waste water of industry witch is hardest to handle.In this text, we use the dyestuff wastewater as the experimental water, in order to find a useable processing technique.In chapter one, the general situation of the dye industry were introduced, such as the classification and the structure of the dye, which can offer necessary support to find suitable processing method of the dyestuff wastewater. The dye especially the macromolecule and organic dye can't be processed by biological treatment directly, the physical method also can't treat the dyestuff wastewater in the limited processing ability. The processing ability here can be understand as the critical point threshold of unit of the finishing agent or handling ability of the wastewater as a result of the structure of the dye.In the second chapter,the treating methods and the usable processing technique which has good treating results were introduced. The common treating methods can be classified by the physical method, the chemical method and biochemical method.Nowadays,with the development of dye which develop for more anti-decomposed and more anti-biodegraded,the dyestuff wastewater can be treated by only one treating method to receive a satisfied effect. The present processing technique develop for multilevel treating technique which is with the axes of anaerobic-aerobic combined treatment and an combination of physical chemistry method and chemical method,﹪in order to attain a perfect objective and receive double effect of environment and economy. The optimization grouping of physical chemistry method and chemical method is the way of the current and nature research. Especially to the dyestuff waster of extra heavy concentration which CODCr is greater than 20000mg/L and a high salinity the optimization grouping of every method can attain better effects. First, a physical chemistry method should be used in order to degrade the anti-decomposed matter for the following treatment which can degrade the waste exhaustively.The processing craft in this text is the micro-electrolysis—flocculation—biological handling craft. The best the condition of experiment was ascertained by experiment, the most suitable Fe/C is 1:1, the reaction time is 30 min. The COD of entering water is about 24000mg/L, and through the micro-electrolysis processing the COD of the waste water can be done away with by 50﹪or so, the BOD5/ COD can raise from subter-0.1 to lager than 0.3, the SO42- can be done away by about 70﹪.The hardness can be 50﹪or so . Adjusting the value of pH to 8~8.5, the COD of discharge water after the micro-electrolysis process can be done away by 10﹪after precipitate.The two testing unit in this text have some commonplace. The first is they have a good hydraulic condition, which is between the CSTR (Continues Stirred-Tank Reactor) and PFR (Plug Flow Reactor). The second is the segmental, then it can form organism which is suitable to its water quality, in this way the processing ability can be raised greatly. The third one is both of the testing unit have a better dent resistance.The major difference between the two units is just the difference between the anaerobic and the aerobic method.Aerobic system can't produce methane, and then the gas trap is unessential, in this cause device is simple. In the aerobic treatment process there is no bad smelly to issue. In addition, the suitability of the aerobic microorganism is better than the anaerobic ones, and aerobic environment is easy to obtain. But the aerobic devices have some deficiency to the anaerobic ones. Such as the dissipation energy of the aerobic process to treat unit contamination is more than the anaerobic one. In addition, in the anaerobic process the most energy of the waste is in the shape of methane to exist beside the little part which removed to the body of microorganism. In this way, the energy is easy to gather, and in the aerobic process the energy usually stay in the anti-degraded materials. That is to say the capacity usage ratio of the anaerobic processing is high than the aerobic one.By the treatment of the ABR, the COD of the waste water can reduce from 4000mg/L to 2000mg/L, but the BOD/COD can promote from 0.3 to about 0.45. Because of the high concentration of the biological, the following treatment has a lot of feasibility. Using the anaerobic sludge as the seeding sludge of the ABR is feasible and the result of it is good. The starting period of the ABR can be divided to four phases. These are the adaptive phase, the domestication phase, the loading raising phase and the stable phase. The upstream velocity of the ABR should be less than 0.25m/h, but shouldn't be less than 0.15m/h. In the later period of the starting phase, the upstream velocity can be promoted to 0.2~0.25m/h. The remove of the waste is progressive, this is the typical characteristic of the PFR. The main removal of the waste is occur in the 1~3 unit of the reactor, with the raising of the organic loading the removal reacting subject move backward. The ABR has a good dent resistance, within only 72 hours the removing ability of reactor can restore ordinarily, but it is lower than before. The PFR characteristic of the ABR make the organic loading of the units longitudinal larger and larger, and then the different coenosis are formed.By the improved process of ABR which is said the aerobic hybrid treating method, the COD of the waste water can be degraded to 100mg/L when the result is good , also 300mg/L when is bad, that can reach the sign to discharge. The COD removal ratio can also reach more than 95﹪.The microorganism hadn't been suitable to the environment in the early time, so degradation of the waste is done by active carbon. As time goes by, the microorganism hade suited the environment and the absorptive ability of the active carbon hadn't lost, so the effect is the best. This is the combined action of the active carbon and the microorganism. With the rising of the COD the running result of the reactor reach stable, and the removal ratio was intent to rise. That is the effect of the microorganism fixed in the active carbon, and then the reactor is started successfully.The testing waste water has a characteristic which is the removal of its chroma and the COD is synchronous, that is to say when the removal result of the chroma is good, the COD may be removed well. Then we can judge the quality of the effluent.Judging by the running result, the processing technique in this text is feasible, with further research, it can be used practically.