Studies On The Protein Extraction From Potato Protein Solution And Wastewater Treatment Process

At present, starch processing enterprises in China take a more extensive mode of operation, numerous high concentration organic wastewater dischargeing become the bottleneck of enterprise development. Therefore, in order to reduce environmental pollution, save water, the utilization of high concentration potato protein solution was researched by this paper.In this paper, potato protein solution as the research object, through the process: determined the composition of potato protein liquid→extracted protein from the protein solution→used physical and chemical, biological methods treated waste liquid→extracted animals dietary protein from the remaining sludge.The high concentration organic wastewater successfully.Firstly, the composition of potato protein solution was analyzed in this paper, indicating great mount of organic matters in potato protein solution, such as cellulose, hemicellulose, starch and total sugar, protein was up to 22.12g/L. Under the process of extraction protein from the potato protein solution, different acids was used and determined HNO3 and H3PO4 to adjuste the pH values, because of high COD removal ratio and providing for the post-biological treatment of nitrogen and phosphorus nutrients. This experiment was determined the isoelectric point of acid and alkali, respectively 4.75,8.50. By the orthogonal test, the best conditions for the extraction of protein is at 50℃, pH 8.6,3h and centrifuged 10min, the rate of protein extraction is 83.0%. Detected protein is rich in amino acids, including humans and animals need to grow seven kinds of non-essential amino acids and eight kinds of essential amino acids. Therefore, the extracted protein is highly nutritious as animal feed.Secondly, after extracted potato protein, protein solution was treated by "aerobic chemical flocculation/adsorption of the electrochemical oxidation" processes.The COD of potato protein solution reduced from 18000 mg/L to 233mg/L and the absorption degree A280 fell to 0.008, that is the removal rate of COD and decolorization ratio were 90%,98% respectively. The treated water is clear and transparent, all the indexes meet the GB20425-2006 industrial water pollutant discharge standards. Finally, using the method of activated sludge to treat wastewater produce large amounts of surplus sludge, this paper was extracted protein from sludge by acid hydrolysis. Through a single factor and orthogonal tests, we determines the optimum extraction conditions:pH 1.00, reaction time 2h, solid-liquid ratio 1:25, reaction temperature 55℃. Under these conditions, the extraction ratio of hydrolysis protein was 57.0%. Not only could the method of extracting protein by hydrolysis realize sludge recycled and reduce, but also can provide for a new source of animal protein feed.