Treatment Of Removing Organic Matters From Indigo Production Wastewater

The indigo as an important reductive dye has been used widely all over the world. It has a lot of merits such as colored equably, faster and difficult to fade.At the same time It also brings some troubles—a mount of wastewater. The problem must be solved, especially during the period of lacking of water.The characters of the wastewater are strong alkaline, large number of organic matters, higher chromaticity, complex ingredient and so on. If we want to reuse the alkaline in the wastewater, we should reduce the organic matters in water. According to the characters of the wastewater, we decide to use these methods to reduce the organic matters, coagulation method, iron-carbon inner electrolysis and activated carbon adsorption.The results show that the coagulation method good at solving the neutral wastewater and the solving conclusion will go badly as the pH of wastewater soaring. In the extremely higher pH condition, the coagulation not reduce the organic matters in the water, but rather improve the value of COD. The iron-carbon inner electrolysis has been used widly in wasterwater treatment and reflected good conclusion of this wastewater. But it is difficult to control, so it's hard to do industrial production.The method of activated carbon adsorption reflects the ideal conclusion to this wastewater. By researching, we get the conclusion that the sequence of factors which affect the COD rejection is the amount of actived carbon> reactive temperature> the time of mix round. In the condition that the amount of actived carbon is 3 g, reactive temperature is 80℃, the time of mix round is 40 min the COD rejective rate is 67.76% to 90 mL wastewater.A line of modified experiments have been made, they are the modification of oxidation, the modification of reduction, the modification of metal loading and the modification of acid-base methods. By experiments, we found that the modifications of KOH and NH3·H2O good at treating this wastewater.In the experiment of KOH modification, the sequence of factors which affect the COD rejection is the density of the KOH> the time of mix round> reactive temperature. In the condition that the density of the KOH is 0.7 mol/L, the time of mix round is 1.5h, reactive temperature is 50℃to 90 mL wastewater.In the experiment of NH3·H2O modification, the sequence of factors which affect the COD rejection is the density of the NH3·H2O> reactive temperature> the time of mix round. In the condition that the density of the NH3·H2O is 3 mol/L, reactive temperature is 40℃, the time of mix round is 3.5 h to 90 mL wastewater.At last we have done the thermaldynamic and dynamic analysises to the actived cabon which have the better conclusion to treat the wastewater. The absorbation process follow the second dynamic model and thethermodynamic model follow the Langmuir and the Freundlich equation.