| Frozen food is a kind of food produced by low temperature and fast-freezing style. Frozen food craft is the important development of the food processing craft; It differs from the general congelation and refrigerates method. Its main characteristic is that the material must be washed and cooked through water, or processed by other pre-process craft, then frozen quickly under low temperature, then stored and transported under -18℃.Frozen food started late in our country, in the 1980's, along with the increase of series of equipments, the processing craft of frozen food is closing to international level gradually, the breed of frozen food also enlarge to the fruit, the vegetable and other processed food from only meat, marine products in the past. At present, there are almost 200 plants which produce frozen food in our country, the species amounts to more than 300, the annual capacity production amounts to 10,000,000 tons. Currently, the output capacity of frozen convenient food has already exceeded Italy to occupy the first of the world.According to measure, frozen food processing factory can discharge wastewater 10-30 tons while producing one ton product, frozen food processing wastewater belongs to high concentration organic wastewater, it will cause serious water environment pollution if it isn't treated properly, which has become one of outstanding problem that restrict the development of frozen food industry. Therefore it is imperative under the situation to resolve the pollution problem of frozen food processing wastewater.There are a great deal of pollutants such as blood stains, grease oil piece, meat scraps, sundries from internal organs and protein in frozen food processing wastewater. As a result, the organic and SS content of the wastewater is high, which can be treated by bio-chemical method. Currently, the general treatment craft adopted in our country include physical-chemical and bio-chemical processing. The study on the treatment of frozen food lags behind compared with other food wastewater such as beer wastewater, alcohol wastewater and amylum wastewater etc. Therefore there are a few related research reports about frozen food wastewater treatment and real engineering projects, there aren't off-the-peg techniques parameter to select. Consequently, it is necessary to study the treatment process of frozen food processing wastewater and its optimization, in order to find feasible crafts and the best operating parameter.On the base of review and comparison: of diverse techniques for treatment of high concentration organic wastewater, this paper presents the feasibility and advantage of Air Flotation + bio-contact oxidation process system in treatment of wastewater from frozen food process. In the experimental phase, the influence of environmental factor on the treatment effect of this system was studied and the optimization of operation condition was explored with witch the theory and experimental basic was established for its application. Then a suit of Air Flotation + bio-contact oxidation process system was designed treatment of wastewater from frozen food process according to the experimental conclusion and correlative data. In the period of actual run, excellent treatment effect was obtained by this process system. The removal rate of COD by the primary Air Flotation process exceeded 70% and reduced the COD load of Follow-on bio-contact oxidation process in favor of sustaining run. 50% of the removal rate of COD by the secondary Air Flotation process make effluent water quality achieve national wastewater drainage standard(GB8978-1996). The bio-contact oxidation pond possesses strong adaptability to the impact load and can steadily supply effluent water quality when the influent water quality changes acutely in a short time. At present, there is scarce report on the treatment of wastewater from frozen food process, so this paper can provide a feasible scheme and project example in this aspect.
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