The waste water generated after sewage treatment is used for discharge 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 the country and the people.
In order to strictly abide by the relevant environmental protection laws and regulations and protect the environment, in line with the "three simultaneities" principle of simultaneous economic construction and environmental protection. At the invitation of investors, based on the previous investigation and a lot of successful practical experience in juice wastewater treatment, our unit compiled the wastewater design scheme of this juice factory for the relevant departments to make decisions and implement.
According to the characteristics of wastewater quality, this scheme plans to adopt conventional air flotation +A/O biological contact oxidation process, which is relatively simple, convenient to operate, low in daily cost and stable in effluent, and the main equipment is steel structure.
The wastewater discharged by this factory is mainly juice wastewater, which contains suspended solids and chroma, and the wastewater has poor biodegradability, mainly inorganic pollution. According to the characteristics of wastewater and our company's experience in treating similar projects, the wastewater is pretreated first, and then the combined biological treatment process is adopted to achieve the ideal treatment effect.
The method comprises the following steps:
Water quality and quantity adjustment, air flotation degumming, anaerobic fermentation decomposition, aerobic treatment, mud-water separation, biological treatment and biological filtration, disinfection and qualified discharge. The process combines air flotation, anaerobic, aerobic and biological aerated filter, which has obvious treatment effect on juice wastewater and stable effluent quality. Direct ultra-fine and efficient air flotation machine is used in air flotation process, which can save engineering investment and operation cost. Suspended matter and organic matter in wastewater can be preliminarily removed by using the principle of air flotation, and 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, precipitation and filtration.
First, the comprehensive sewage enters the regulating tank through the sewer pipe, and then the sewage is lifted by the pump to the air flotation machine 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. The water after air flotation flows into the aerobic biological treatment unit-immobilized biological aerated filter. Aerobic biological treatment usually adopts activated sludge method and biofilm method. Activated sludge process (oxidation ditch, SBR, plug-flow aeration tank) is stable and mature, but the impact resistance of activated sludge is poor, the removal rate is low, especially for the sewage with poor biodegradability, and it occupies a large area, consumes high power, has complex operation and management, and takes a long time to cultivate sludge, especially during the maintenance of the factory.
Immobilized biological aerated filter integrates adsorption, oxidation and filtration, with good treatment effect, less sludge, low energy consumption and good effluent quality. This is an advanced water treatment process at present. In traditional biological treatment, it is often difficult to degrade and inhibit microorganisms, resulting in high effluent quality and low microbial activity in the system. The efficient microorganisms adopted by our company overcome this shortcoming. This product strengthens and modifies natural microorganisms by means of genetic engineering, 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 organic matter is converted into carbon dioxide and water by aerobic microorganisms. The effluent of immobilized biological aerated filter can reach the standard after precipitation.
Process flow chart:
Fruit juice wastewater-grid well-water collection tank-regulating tank-high efficiency air flotation machine -A-class oxygen tank -O-class oxidation tank-secondary sedimentation tank (inclined tube sedimentation)-sludge tank-quartz sand filtration device (equipped with backwashing device)-activated carbon dilution device (equipped with backwashing device)-can meet the discharge standards.