The sewage discharged from this fruit juice factory is high-concentration organic wastewater, which has the characteristics of extremely high COD concentration, ordinary biodegradability and high chroma. According to the relevant provisions of the State Environmental Protection Agency, the discharged sewage must be treated to meet the standards before it can be discharged into municipal sewage pipelines or incorporated into nearby waters.
The generated wastewater is used for discharge after sewage treatment or for green space irrigation, car washing, toilet flushing and ground flushing. It can not only increase water resources, but also reduce sewage discharge, which is a good thing for both the country and the people.
in order to strictly abide by the relevant environmental laws and regulations and protect the environment, we adhere to the principle of "three simultaneities" in which economic construction and environmental protection are carried out simultaneously. At the invitation of investors, on the basis of preliminary investigation and a number of successful practical experiences in juice wastewater treatment, our unit has compiled the wastewater design scheme of this juice factory for decision-making and implementation by relevant departments.
according to the characteristics of the wastewater quality, the conventional air flotation plus "A/O biological contact oxidation" process is proposed in this scheme. The treatment process is relatively simple, convenient to operate and run, with low daily cost and stable effluent. The main equipment is steel structure.
The wastewater discharged from this factory is mainly fruit juice wastewater, which contains suspended solids and has poor biodegradability, mainly inorganic pollution. According to the characteristics of the wastewater and the experience of our company in treating similar projects, the wastewater is pretreated first and then the combined biological treatment process is used, so that the wastewater can achieve the ideal treatment effect.
The process includes the following steps:
Adjustment of water quality and quantity, air flotation degumming, anaerobic fermentation decomposition, aerobic treatment, mud-water separation, biological treatment and biological filtration, disinfection and qualified discharge. The process adopts the combination of air flotation, anaerobic, aerobic and biological aerated filter, which has obvious treatment effect on juice wastewater and the effluent quality is stable and up to standard. In the air flotation process, a direct ultra-fine high-efficiency air flotation machine is adopted, which can save engineering investment and operation cost. Components The suspended matter and organic matter in wastewater can be preliminarily removed by using the air flotation principle, and the suspended matter in wastewater can be removed by adding flocculant into the water inlet pipeline, which also saves the complicated processes such as conventional flocculation, sedimentation and filtration.
firstly, the comprehensive sewage enters the regulating tank through the sewer pipe, and then the sewage is lifted to the air flotation machine by the pump for solid-liquid separation, so that the effluent becomes clear, and most suspended and colloidal solid substances are separated from the sewage. The concentrations of SS, COD and BOD5 decreased significantly, and the concentrations of Cr3＋+and S2- in the effluent could meet the needs of subsequent biological treatment. After air flotation, the water flows into the aerobic biological treatment unit-immobilized biological aerated filter. Aerobic biological treatment usually adopts activated sludge method and biofilm method. The activated sludge process (oxidation ditch, SBR and plug-flow aeration tank) is stable and mature, but the activated sludge has poor impact resistance and low removal rate, especially for the sewage with poor biodegradability. Moreover, it occupies a large area, consumes high power, has complicated operation and management, and takes a long time to cultivate sludge, especially during the maintenance of the factory, so the sludge must be re-cultivated.
Immobilized biological aerated filter (BAF) integrates adsorption, oxidation and filtration, which has good treatment effect, less sludge, low power consumption and good effluent quality. It is an advanced process for water treatment at present. In traditional biological treatment, it is common that it is difficult to degrade and will inhibit microorganisms, resulting in high effluent quality and low microbial activity in the system. The high-efficiency microorganism adopted by our company overcomes this shortcoming. This product strengthens and modifies natural microorganisms by means of genetic engineering, which improves the activity and adaptability of microorganisms and can effectively degrade refractory organic substances in sewage.
Sewage enters the biological aerated filter for aerobic treatment, and the organic matter is transformed into carbon dioxide and water by aerobic microorganisms. The effluent from the immobilized-aerated biofilter can be discharged after the sedimentation process.
2.3.2: Process flow chart:
Fruit juice comprehensive wastewater-grid well-water collecting tank-regulating tank-high efficiency air flotation machine-A-class oxygen tank-O-class oxidation tank-secondary sedimentation tank (inclined tube sedimentation)-sludge tank.