Treatment level of industrial wastewater and treatment method of wastewater before painting

2018/08/17

Treatment level of industrial wastewater and treatment method of wastewater before painting

Industrial wastewater is divided into three levels according to its treatment procedures and requirements:

Primary treatment: pretreatment by mechanical method or simple chemical method can make suspended matter or glue in the wastewater precipitate, and can initially neutralize pH.

Secondary treatment: The main purpose is to solve the pollution problem of decomposable or oxidized organic dissolved matter or partially suspended solid matter. Biological treatment or addition of coagulant is often used to separate and suspend solid suspended solids. Secondary treatment can greatly improve water quality, and most of them can meet discharge standards.

Tertiary treatment: Also known as advanced treatment, it is mainly used to treat difficult-to-decompose organic matter and inorganic matter in solution. Treatment methods include activated carbon adsorption, ion exchange, electrodialysis, reverse osmosis, and chemical oxidation. After three-stage treatment, the quality of wastewater can meet the water quality standards of surface water, industrial water or domestic water.

The above-mentioned method can also be adopted for the treatment of pre-painting wastewater. In Japan, the secondary treatment method and incineration treatment method are mainly used. The secondary treatment method is to treat the pre-painted sewage through a primary treatment, and then use activated sludge for biochemical treatment, and then discharge it, and the sludge can be used as fertilizer; the incineration treatment method is to concentrate the chemical sewage, filter it and use it after precipitation. The incinerator treatment can achieve good results, making the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of the discharged wastewater lower than 20 mg / g and 15 ml / liter, respectively.

CPIn Europe, the CP wastewater treatment system is used, with less investment. It can directly remove solid suspended solids, heavy metals, solvents, resins, fillers, emulsifiers and pollutants from wastewater. The effect is very good, and it is very popular among small and medium-sized enterprises. As an auxiliary means, coating plants and workshops with large sewage discharge volume are also effective in treating special components in the main stream.

The basic principle of the CP method is that most sewage can be satisfactorily treated by putting in a suitable treatment agent at one time.

In the CP method, a variety of different treatment agents are used, which not only have a destructive effect on stable emulsions, but also can neutralize, absorb, adsorb, and flocculate pollutants that are in a stable state and are not easy to filter out. It cannot remove pigments in wastewater, Solvent, latex, suspending agent, filler, thickener, etc. For specific wastewater, the "mix and match" method can be adopted to ensure the best treatment effect.