Characteristics of oily wastewater:
A large amount of oily wastewater is produced in the petrochemical, metal industry, machinery industry, food processing and other industries. According to statistics, at least 5 to 10 million tons of oil pollutants enter the water body through various channels every year in the world, which has seriously affected and damaged the environment and endangered human health. Oily wastewater is a large-scale and serious industrial wastewater with high COD and BOD values, certain odor and chromaticity, flammable, easy to oxidize and decompose, and difficult to dissolve in water.
Treatment method:
The method for treating oily wastewater needs to be selected according to the specific composition of the wastewater. Generally, there are physical and chemical methods, chemical methods, and biological methods. However, these methods have limitations. Several methods can be combined and used in stages to achieve good oil removal effects.
1. Flotation method: The flotation method is to introduce air into the wastewater, and use highly dispersed microbubbles to increase the buoyancy, thereby increasing the floating speed. Therefore, the oil-water separation efficiency is very high. It can be used for the separation of solids and solids, solids and liquids, and liquids and liquids. At the same time, adding coagulants to the wastewater can also achieve oil removal effects.
2. Adsorption method: The adsorption method uses porous solid adsorbents to perform surface adsorption on dissolved oil and other soluble organic matter in oily wastewater. Activated carbon is the most commonly used adsorbent. It has strong adsorption capacity but high cost and difficulty in regeneration. In addition, its adsorption is limited, which limits its application. Therefore, finding a suitable adsorbent has become a pressing problem to be solved.
3. Membrane separation method: The membrane separation method uses porous membrane separation media to intercept oil and surfactants in oily wastewater and allow water molecules to pass through, thereby achieving the purpose of oil-water separation. This method has the advantages of no phase change and low energy consumption during the separation process.
