Study On Dialysis Of Yam Diosgenin Hydrolytic Wastewater In Homogeneous Ion Exchange Membrane

Diosgenin wastewater consists of diosgenin washing wastewater, hydrolysatewashing wastewater and hydrolysis liquid waste. Hydrolysis liquid had a greatinfluence on the subsequent biological treatment because of high chromaticity, highacidity, high salt content and high concentration of organic matter. At present, thecommonly treatment process used for diosgenin wastewater is anaerobic–aerobicbiological treatment process and supplemented by pretreatment method such asneutralization, catalytic oxidation. However, the processing cost is high, and consumeslarge amounts of neutralization agent. So far, there have few reports about thehomogeneous ion exchange membrane dialysis method dealing with diosgeninhydrolysis wastewater. Aimed at the difficulties of diosgenin wastewater treatment,diosgenin hydrolysis wastewater was concerned as the research object, and dialysisregulation of yam diosgenin hydrolytic wastewater in homogeneous ion exchangemembrane was studied in this project. The objectives of this investigation were doingsome basic research for the feasibility of dealing with this kind of wastewater byelectrodialysis method and providing a new treatment process for diosgeninwastewater.A three-cell electrodialysis device was used to treat hydrolytic wastewater. Thetreatment effects by dialysis when the device was not energized and by electrodialysiswhen the device was energized have been studied. The influences of waste liquidconductivity, salt content, concentration of hydrogen ion, concentration of sulfate, Ca, Mg, and organic matter have been investigated. The following conclusions can beobtained:(1) To deal with diosgenin hydrolysis wastewater by dialysis technology canachieve good effect of desalination rate, and desalination rate can reach71%after100hour. SO42-still has a tendency to reduce, and recovery rate was78%。(2) There is about90%of the organic matter is less than5K of small molecularweight organic compounds in the diosgenin hydrolysis wastewater. Most organicmolecules is membrane-impermeable in the process of dialysis and electrodialysis. TheCOD interception rate can reach74%and96%respectively. Thus the separation oforganic and inorganic substances can be effectively achieved.(3) The operating voltage has a great influence on the treatment effect. Ionmigration velocity was significantly increased along with the increase of the voltage.The higher the voltage, the shorter the time needed when the same desalination rateand the same recovery rate of sulfate was achieved.(4) Compared with dialysis operation, electrodialysis operation is used to dealwith diosgenin hydrolysis wastewater can be achieved good processing effect in arelatively short period of time.