Study On Treatment Of Simulant Dye Waste Water By Supercritical Water Oxidation

China is a big dye-producing country. In the process of dye-producing, there will be a lot of waste water which will cause a big pollution to the environment. Dye waste water has a character of high pollution concentration, high chroma, high mineral concentration, complex composition and bad biological degradation ability. Moreover, more and more kinds of dyes are coming out and they are more difficult to be degraded by light, oxidation and organism. It makes the dye waste water more difficult to treat so it is always the hot pot of waster waste water treatment.Supercritical water oxidation is a new method of water treatment. According to the characteristic of supercritical water, this paper described the feature of the supercritical water oxidation and summarized all the reseatches which have been done in this field. Using an apparatus of supercritical water oxidation, the paper did some researches on the degradation of Disperse Red 3B waste water. The results concluded that:(1) Disperse dye waste water could be treated effectively by Supercritical water oxidation. Both the COD and chroma could be greatly improved. In the condition as: pressure was 25MPa, oxidant dose was 1.2, temperature was 420℃, resident time was 30s, the COD removal efficiency could be 92.80% and the chroma removal efficiency could be 99.30%.(2) Temperature, pressure, resident time and oxidant dose were main factors to affect the reaction. The COD and chroma removal efficiency of disperse dye waste water would be higher when the temperature and pressure went higher, the resident time went longer and the oxidant dose increased.(3) In the treatment of disperse dye waste water by supercritical water oxidation, the removal efficiency of TOC was higher than that of TN.(4) The TN concentration would decrease when the the temperature, pressure and the oxidant dose increased. While the NH₃-N concentration would increase when the the temperature, pressure and the oxidant dose increased.(5) In the process of supercritical water oxidation, organic nitrogen would firsrt be oxidized to NH3-N and finally to N₂, which meant the nitrogen was completely removed from the water. During the treatment, there would be a lot of NH₃-N, which suggested that NH₃-N was more difficult to be oxidized and it was controlling path of the organic nitrogen taring into N₂.(6) After the treatment by supercritical water oxidation, the degradability of the organic pollutant would be greatly increased.(7) According to the analysis of the product of supercritical water oxidation, the paper presumed the possible path of the degradation.(8) By comparison, the paper approved that transpiring wall-type reactor could stop the corrosion effectively.(9) Salt sediment problem would build up the ceramic tube so we should take some measures to prevent it.