Treatment technology of reclaimed water reuse can be divided into physical and chemical method, biochemical method and chemical method. Usually technology need a reasonable combination of a variety of sewage treatment technology, a variety of water processing method combined the advanced sewage treatment, this is because a single water processing method is generally difficult to achieve water quality requirements. Development to the present, the water reuse process:
Biochemical method
Biochemical method (referred to as biochemical method) the use of natural survival of various bacteria, the decomposition of organic matter in waste water into harmless substances, so that the waste water can be purified.
The raw water, the grid, the regulating pool, the contact oxidation tank, the precipitation ground, the filter, the disinfection and the water outlet.
Biological chemical method can be divided into activated sludge process, biological membrane method, biological oxidation tower, land treatment system, anaerobic biological treatment method and other methods.
1, activated sludge process
(1) blast aeration, drainage flow aeration, the compressed air is constantly to drum into wastewater to ensure certain amount of dissolved oxygen in the water, in order to maintain the life activities of microorganisms, decomposition of organic compounds in water, in order to achieve the effect of sewage purification.
(2) mechanical aeration: the surface aeration, equipment used in aeration tank mechanical impeller rotating, churning the water, the oxygen in the air dissolved in the water, for microbial life activities, biochemical function to achieve the effect of sewage purification.
(3) pure oxygen aeration: it is according to the aeration method to blowing oxygen in water, in order to improve the efficiency of oxygenation, thus speeding up the sewage purification speed.
(4) deep well aeration: an aeration device with a diameter of 0.5~6.0m and a depth of 50~60m, using water pressure to increase the rate of oxygen transfer in water to improve its efficiency.
2, biological membrane method
(1) the biological filter: the waste water flows through the biological membrane which grows on the surface of the filter material, through the material exchange between the two sides and the biochemical function, causes the organic matter in the waste water to degrade, achieves the purification goal.
(2) rotating biological contactor: by fixed on the horizontal axis of several spacing is very near the disc, we the rotation of the disk surface growth layer of biological membrane, to purify the wastewater.
(3) biological contact oxidation: all of the microorganisms attached to the microorganism are immersed in waste water, and the mechanical equipment is used to charge the waste water into the air, so that the organic matter in the wastewater is degraded, and the waste water is purified.
3, biological oxidation tower: the use of microorganisms in water algae, aquatic plants, such as aerobic or anaerobic biological treatment of wastewater treatment of natural or artificial pond.
4, land treatment system
(1) infiltration land: the film for soil microbes and plant roots of pollutants purification ability (filtration, adsorption, microbial decomposition, etc.) to treatment of domestic sewage, the sewage in the water and fertilizer to promote the growth of crops, grass and trees.
(2) sewage irrigation: the main purpose is to make full use of the sewage after purification.
5, anaerobic biological treatment: the use of anaerobic microorganisms (such as methane, etc.) to decompose organic matter in sewage, to achieve the purpose of purifying water, while producing methane gas, CO2 and other gases. Anaerobic biochemical treatment is mainly used to treat high concentration organic wastewater and sludge nitrification treatment.
Physical and chemical method
The raw water, the grid, the regulating pond, the flocculation settling tank, the ultrafiltration membrane, the disinfection, the water outlet.
Method for purifying waste water by using physical and chemical synthesis. Usually refers to the composed of physical and chemical methods of wastewater treatment system, or refer to physical and chemical processes of a single processing method, such as flotation, stripping, crystallization, adsorption, extraction, electrolysis, electro dialysis, ion exchange, reverse osmosis, and so on.
In 1935, W. Rudolf and E.H. began torneko's physical and chemical treatment system of sewage treatment test. Industrial effluent water quality have become more and more complicated with the development of the industry, and many pollutants in wastewater, such as heavy metal ions that commonly used biological treatment method is difficult to remove; it is difficult to degrade many complex organic compounds, biological; of toxic pollutants concentration exceeds the tolerance limit of microorganism and biological treatment method does not apply. In order to protect the environment and rational use of water resources, wastewater discharge standards are more and more strict, the rate of wastewater reuse requirements are getting higher and higher. Therefore, since 70s, physical and chemical treatment method has been widely attention and rapid development.
Physical and chemical treatment can not only be an independent treatment system, but also can be a biological treatment of the follow-up treatment measures. The choice of the process depends on the water quality, discharge or recycling of the water quality requirements, processing costs, etc.. In order to remove the suspended and dissolved pollutants and the use of chemical coagulation - precipitation and activated carbon adsorption of the two treatment, is more typical of a physical and chemical treatment system. The treatment process is the addition of lime in the waste water, rapid mixing, flocculation and precipitation, remove most of the suspended and colloidal substances, while removing a portion of the phosphate. After precipitation of water, flow through activated carbon contact bed, due to the adsorption of activated carbon, remove dissolved contaminants, such as dissolved organic matter, etc.. Activated carbon to carry out anti flushing and regeneration. Precipitation pool sediment after dehydration and calcination, the lime can recycling; calcination carbon dioxide gas can be adjusted sedimentation effluent pH. Through this system, the water quality of the representative data is: 5mg (biochemical oxygen demand) L / COD, 15mg (chemical oxygen demand) BOD / L, suspended 5mg / L, phosphorus 0.15mg / L, nitrogen 2.6mg / L. If there are other requirements for water quality, it can also increase the corresponding processing process, such as in order to further