Industrial wastewater refers to the wastewater, sewage, and waste liquid generated during the industrial production process, which contains industrial production raw materials, intermediate products, and products lost with water, as well as pollutants generated during the production process.
With the rapid development of industry, the types and quantities of wastewater are rapidly increasing, and the pollution of water bodies is becoming increasingly widespread and serious, posing great harm to human health and safety. If the toxicity is high, it can lead to the death or even extinction of aquatic animals and plants. Polluting groundwater, thereby contaminating crops; Infiltration into the soil, causing soil pollution. Affects the growth of microorganisms in plants and soil; Some industrial wastewater also has an unpleasant odor and pollutes the air.
Zero discharge of desulfurization wastewater - three specific wastewater treatments
1. Zero discharge and treatment process of desulfurization wastewater from coal-fired power plants
Power plant desulfurization wastewater treatment process: desulfurization wastewater → wastewater tank → wastewater pump → pH neutralization tank → sedimentation tank → flocculation tank → clarification tank → effluent tank → effluent pump → standard discharge
The desulfurization wastewater treatment system includes three parts: wastewater treatment, dosing, and sludge treatment. The wastewater treatment system mainly consists of waste water tank, triple box, clarifier, mud pump, outlet water tank, clean water pump, fan, dewatering machine and other equipment. In addition to a large amount of Cl - and Mg2+, impurities in desulfurization wastewater also include fluoride, etc; Heavy metal ions, such as Cu2+, Hg2+, etc; Insoluble CaSO4 and fine dust. In order to meet the wastewater discharge standards, corresponding wastewater treatment devices are required.
2. Chemical wastewater
Firstly, transform the production process and equipment to reduce pollutant emissions, eliminate wastewater discharge, and achieve comprehensive utilization and recycling; The treatment level of wastewater to be discharged should be selected based on water quality and requirements.
The treatment mainly separates suspended solids, colloids, floating oil or heavy oil in water. Water quality and quantity regulation, natural sedimentation, and floating oil separation can be used.
Secondary treatment mainly involves removing biodegradable organic dissolved substances and some colloidal substances, reducing the biochemical oxygen demand and some chemical oxygen demand in wastewater, usually using biological treatment. There is a considerable amount of residual COD in the wastewater after biological treatment, sometimes with strong color, aroma, and taste, or due to high environmental hygiene standards, a three-level treatment method needs to be used for further purification.
The tertiary treatment mainly involves removing organic pollutants that are difficult to biodegrade and dissolved inorganic pollutants from wastewater. The commonly used methods include activated carbon adsorption and ozone oxidation, as well as ion exchange and membrane separation techniques. Various chemical wastewater can be treated using different methods according to the requirements of different water quality, water quantity, and external drainage water quality after treatment.
3. Heavy metal wastewater
The treatment of heavy metal wastewater can usually be divided into two categories:
One method is to convert dissolved heavy metals in wastewater into insoluble metal compounds or elements, and then remove them from the wastewater through precipitation and flotation. Applicable methods include neutralization precipitation method, sulfide precipitation method, flotation separation method, electrolytic precipitation (or flotation) method, membrane electrolysis method, etc;
The second is to concentrate and separate heavy metals in wastewater without changing their chemical forms. The applicable methods include reverse osmosis, electrodialysis, evaporation, and ion exchange. Based on the quality and quantity of wastewater, these methods should be used in multiple bands or combinations.
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