Study On The Treatment Of The Wastewater Of Dietary Fiber From Small Wheat Bran With Membrane Separation Technology

In recent years, modem nutrition research results of clinical and epidemiological investigations have established that serious threat to human health, cardiovascular disease, diabetes, gallstones and certain types of cancer incidence, and the intake of human diet food fiber was negatively correlated. The strengthen functions of dietary fiber foods in Europe and the United States and Japan, and other developed countries were prevail. Daily added a certain amount of dietary fiber, and a balanced diet is imperative. Vigorously develop dietary fiber from wheat bran and other dietary fiber products has become very important. THE wastewater from the process of Preparation of wheat bran dietary fiber contains dissolved organic matter. Analysis of wheat bran dietary fiber production process wastewater, the use of membrane separation technology to deal with wheat bran dietary fiber wastewater, and through the use of activated carbon adsorption, adsorption method of coagulation and membrane separation technology, we think that the membrane separation technology in wastewater treatment and useful resource recovery side is excellent.According to the character of dietary fiber from wheat bran waste water, we the chromaticity, pH and so on each target. We use the different molecular weight of polysulfone hollow-fiber ultrafiltration membrane to treat the wastewater of dietary fiber from wheat bran. According to the results, We chose the molecular weight of 5000analyzed in the water sample the main pollutant (protein, starch, sugar et)content, and analyzed the chemical oxygen demand (COD_Cr), the biochemical oxygen demand (BOD₅), the turbidity, polysulfone hollow-fiber ultrafiltration membrane to deal with wheat bran dietary fiber wastewater. When the pressure of 0.04, temperature of 30℃, inlet flow of 35.568 L/h, pH of6, the highest removal of COD_Cr reaches 69.63%; the effici-ency removal of turbidity reaches 92.22%; the efficiency removal of color rea-ches 87.5%. Through ultrafiltration liquid with 4040-UHA-ESNA roller NF membrane components in the pressure of 0.11MPa.Concentrated liquid flow of 700L/h, the NF liquid flow of 40L/h, te-mperature of 26℃, the removal of COD_Cr was 98.57%, the removal efficiency of turbidity was 99.14%, the removal of Color was 100%, the quality of water reached to the national first category of the first pollutant emission standards.In the process of ultrafiltration, we has carried on the interception of the protein, the starch, the return to original state sugar and the SDF in the waste water. The result indicated that the protein interception rate may reach 100%, the starch interception rate was 99.2%, the sugar interception rate was 98%, the SDF interception rate was 92%.In the process of ultrafiltration, we also inspected the pressure, temperature, flow, pH and other factor on the flux. The results showed: When the pressure was 0.11MPa, temperature was 35℃, the flow was the 35.568L/h, pH was 11.55, the flux was largest, reaching 77.46 L/h.m². After the end of the ultrafiltration, membrane components for washing, we use NaOH washing, and STPP+SDBS+NaOH+eionized water, ethylenediamine tetra sodium+STPP+deionized water, citric acid+deionized water of the four methods for washing membrane components.The results showed membrane components ultrafiltrated in two hours later, the membrane flux can resume 90% with NaOH+STPP+SD BS+deionized water washing for 1 hours, and the flux can also resume 82% with 0.5% NaOH washing for 1 hours and the use of Ethylenediamine tetra sodium+STPP+deionized water or citric acid+deionized water washing membrane was instead of fouling. Therefore we choose NaOH+STPP+SDBS+deionized water as the most efficient method of washing.Also, we used PAFS as main coagulant, cationic polyacrylamide as coagulant and activated carbon adsorption to treat wheat bran dietary fiber wastewater. The results showed that when the PAFS (polyaluminum ferric sulfate) for 500mg/l, Polyacrylamide (PAM) for the 10mg/L, pH 4.21. The treated wastewater removal of COD_cr was largest. AFter flocculation water was adsorpted by activated carbo. when activated carbon dosage of 50g/l, the temperature of 55℃, contact time of 20 minutes, Ph＜5, the removal of COD_Cr was up to 85.82%; the removal rate of color was 100%, the removal of turbidity was 93.03%. At that time, the water quality was up to the third emission standards of the national first pollutantsWhen treatment wheat bran dietary fiber wastewater with activated carbon adsorption alone, The addition of activated carbon content of 160g/l, temperature of 55℃, the contact time of 20 minutes, the pH＜5, Stiring for 5 minutes and the static. The removal wastewater of COD_Cr was up to 96.89%. BOD₅ could reach 96.61% ans the water could up to the third emission standards of the national first pollutants.Finally, we also used ultrafiltration with the activated carbon adsorption to treat the waste water of the small dietary fiber from wheat bran. The experimental results indicated, When the operation pressure of ultra filter was 0.03MPa, the temperature was 25℃, the flow was 35.586L/h, The addition of activated carbon content was 30g/l, the removal rate of COD_Cr was 90.59%, the removal rate of BOD₅ was 90.44%, the color was 0, the turbidity was 1.7, and the water quality was up to the third emission standards of the national first pollutantsFrom the above three types of treatment process of wheat bran dietary fiber wastewater, costs of Wheat bran can dietary fiber wastewater treatment was roughly estimated. By comparison, we think approach of membrane separation technology is both economical and effective.