Recycling treatment process of waste plastic cleaning wastewater
With the continuous development of plastics industry, plastics, as one of the most widely used basic materials, plays an important role in the development of various industries. In the recycling process of waste plastics, it is necessary to clean the surface impurities of waste plastics. The most common cleaning medium is water. At the same time, in the primary processing process of waste plastics, hydraulic separation is usually used to separate metal, sand and other sundries of different varieties of plastic products, whether cleaning or sorting, The impurities and dirt on the surface of waste plastics will be brought into the water, resulting in cleaning wastewater. The pollutants in the cleaning wastewater are mainly various substances attached to waste plastics. The pollution caused by different varieties and sources of waste plastics is also different. The more common main pollutants are suspended solids, organic matter, oil, soluble matter, etc. due to their complex composition, it is difficult to treat wastewater. According to relevant literature statistics, 2 ~ 4 tons of water is required for each ton of waste plastics cleaned, depending on the cleanliness of waste plastics. Therefore, a large amount of wastewater will be generated in the process of waste plastics cleaning and processing. Due to the large amount of waste plastic cleaning wastewater and complex pollutant composition, it brings great pressure to the waste plastic cleaning and processing industry.
At present, this kind of wastewater is mostly treated by simple physical and chemical methods in the industry and then recycled, resulting in serious deterioration of water quality, difficulty in cleaning wastewater treatment, reduction of reuse rate, increase of clean water consumption, and even odor after cleaning of waste plastics, affecting the quality of recycled waste plastics. Therefore, improving the recycling rate of waste plastic cleaning wastewater, maintaining the quality of recycled water, preventing the deterioration of cleaning water and reducing the consumption of clean water have become an urgent demand in the industry.
The wedge wire screen filter element overcomes the shortcomings of the prior art and provides a circulating system and treatment process of waste plastic cleaning wastewater. By optimizing the process layout, the invention forms a process system of three-stage circulation and step-by-step treatment, improves the recycling utilization rate of cleaning wastewater, and can effectively avoid the problems of blackening, odor, water quality deterioration and so on in the recycling process of cleaning wastewater.