1 soy sauce brewing wastewater sources and characteristics
Present, China’s soy production to the north of the “low-salt solid-state technology,” and the South’s “high-salt liquid process” based. Ordinary soy sauce production process including raw material processing, starter, fermentation, extraction and so pour the oil and heating the preparation process. Soy sauce, water is a high organic content Food Fermentation wastewater. The main components of food residues such as chopped bean crumbs, bran, flour, sugar, soy sauce, fermentation residues, secreted by a variety of microbes and microbial enzymes and metabolites, soy sauce, pigment, trace detergents, disinfectants and a little salt, etc. , color high, wastewater treatment has a certain degree of difficulty.
2 soy sauce and difficult waste water treatment
(1) high color. Soy sauce waste pigment is part of the most difficult to remove, soy sauce pigment mainly composed of two parts: First, during the fermentation of soy sauce, sugar and ammonia as reaction (Maillard reaction) to form black; followed by the deployment as artificial added products caramel. The two substances are very complex polymer structure, so far not understand its molecular structure. Which contains a chromophore group consists of the following two or two or more conjugated chromophore substrate.
3 Sauce Wastewater Treatment Technology Colorific these conjugated organic molecules to produce absorption in the visible region, so that water has a color. Experience has shown that Activated Carbon Adsorption, electrolysis and other methods of color removal of such waste water is not ideal, and in the oxygenation process of blowing off a deeper color trends. Removal of the red substance in water is difficult sauce wastewater treatment, so far little achieve a discharge standard of reporting.
(2) high salinity: salt is one of the main raw material for production of soy sauce, soy sauce, soy sauce, water in the wash water tank, filter cloth washing water is salt Sewage , Salt content of 1 ~ 5% (about 10000 ~ 50000mg / L). Although the production of waste water and soy sauce factory, after other common water and mix thoroughly to reduce salt content, but still at a high level of salinity. Salinity on physico-chemical treatment processes have little effect, but in contact with corrosive to metal equipment, will shorten the life of the equipment. In addition, the high salinity of the biological treatment process has significant influence.
(3) the impact of a large load change. Seasonal changes in water quality soy sauce is another difficult process of wastewater treatment. Most of the relative concentration of soy sauce factory starter season, especially with the soy sauce factory especially exposed drying process. Wastewater and other wastewater koji different in nature, starter when the bubble will have a high concentration of material waste, so COD up to 20000mg / L or so, to the soy sauce waste water treatment is very difficult. Factory mode of production to market ability, resulting in great fluctuations in water quality, impact load change is large, the same time, so that the normal operation of biological treatment facilities were greatly affected.
(4) pollutant components unstable. Some types of soy sauce production complex enterprise products, often including soy sauce, dark soy sauce, red vinegar, chili sauce, garlic sauce, vinegar, oil consumption, fermented bean curd and other products, which makes water a more complex composition, governance more difficult.
(5) sludge biological treatment process with high yields. Soy sauce, water is a high concentration organic wastewater, the current wastewater treatment process common soy sauce is still represented by activated sludge biological treatment as the main method. Biological treatment process of sludge generated by a large number of usually contain a lot of instability in organic, biological treatment is a major problem. Sludge generally composed of loose material, which is characterized by: high moisture content, sludge volume up to the solids volume of the number of times; from a variety of microbial strains formed micelles and its adsorption of organic and inorganic composition such as with N, P, K and trace elements, organic matter and harmful pathogens, parasite eggs, heavy metals and some organic matter such as refractory. As the huge volume of sludge, the nature of unstable, highly corrupt, is not conducive to the transport and disposal of Environment Will result in direct or potential threat. Current sludge treatment and disposal, there is both effective and economical problems. First of all, there is no one kind could by extension the environment clean and effective way; Second, a variety of sludge treatment and disposal method requires a lot of money. In addition, with increased production of soy sauce, soy sauce wastewater treatment capacity and treatment rates have increased, the amount of sludge generated will be rapidly increasing, soy sauce, wastewater treatment sludge generated by the effectiveness of treatment and disposal, wastewater treatment technology is the key soy sauce . As China’s urban economic development and population growth, environmental pollution worsened environmental awareness to strengthen and improve the environmental quality requirements, must make more high-density, high color soy sauce industry need to be addressed, and this special sludge is also a need to consider.
(A) adsorption Adsorption is the dissolved chemical and physical separation of pollutants. Wastewater adsorption treatment, mainly refers to the use of solid adsorbent physical adsorption and chemical adsorption, removal of various pollutants in wastewater process, dealing with objects as highly toxic substances and biological degradation of pollutants is difficult. Adsorption can be divided into physical adsorption, chemical adsorption and ion exchange adsorption of three types. The main factors affecting the adsorption: (1) the physical and chemical properties of adsorbent; (2) physical and chemical nature of the adsorbate; (3) waste water pH; (4) Wastewater temperature; (5) the impact of coexistence substances; ( 6) contact time. Common adsorbents are activated carbon adsorbent resin (resin), humic acid adsorption. Adsorption process mode of operation, static and dynamic batch adsorption of two successive adsorption.
Currently used for soy sauce wastewater treatment include activated carbon adsorption and cinder, sand filtration adsorption. For the part of the organic carbon has strong adsorption for metal ions and some inorganic substances have a certain adsorption capacity, but because of the color of soy sauce waste high, direct use of activated carbon to remove less effective, but activated carbon would have damaging effects, so often with activated carbon adsorption and flocculation for.