Coal washing wastewater is a kind of industrial wastewater generated in the process of coal processing, which mainly comes from the mechanical washing and transportation of coal. This wastewater contains a large amount of harmful substances such as suspended solids, heavy metals and acidic substances, and if it is discharged directly without treatment, it will cause serious pollution to the environment. Therefore, it is necessary to effectively treat coal washing wastewater. Filter press is a commonly used solid-liquid separation equipment, through the filter press treatment technology can effectively remove harmful substances such as solid suspended solids and heavy metals in coal washing wastewater, and at the same time, it can also improve the useful substances in wastewater.
1. The treatment process of the filter press for coal washing wastewater.
The treatment process of coal washing wastewater filter press mainly includes the following steps:
1.Pretreatment.
The purpose of pretreatment is to remove large particles of suspended solids and impurities in the wastewater and provide cleaner wastewater for the subsequent treatment process. Commonly used methods include natural precipitation, screening, flotation, etc. Through these methods, hazardous substances such as suspended solids and heavy metals can be preliminarily removed from wastewater.
2.Adjust the pH level.
Due to the low pH value of coal washing wastewater, it is not conducive to subsequent treatment and **. Therefore, the pH of the wastewater needs to be adjusted to the neutral or weakly alkaline range. A common way to adjust the pH is to add an appropriate amount of an alkaline substance such as lime or sodium hydroxide.
3.Coagulation precipitation.
Coagulation and sedimentation is the use of chemicals to form large flocs such as suspended solids and heavy metals in wastewater, and then remove them by precipitation. Commonly used coagulants include aluminum salts, iron salts, polymers, etc. By coagulation and sedimentation, harmful substances in the wastewater can be further removed.
4.Filter press.
After pretreatment, pH adjustment and coagulation and precipitation, the harmful substances in the wastewater have been well removed. Filter press is a commonly used solid-liquid separation equipment, through which the solid suspended solids and heavy metals and other harmful substances in the wastewater can be completely separated. The working principle of the filter press is to use a high-pressure pump to feed the wastewater into the filter press, and the water in the wastewater is forcibly discharged by pressurization, while the solid matter is left on the filter cloth of the filter press, and finally forms a filter cake.
5.Dehydration.
After the press filtration, the solids in the wastewater have been separated, but still contain a large amount of water. In order to facilitate the transport and handling of solid substances, dewatering treatment is required. Commonly used dehydration methods include natural drying, tumbling, centrifugal separation, etc. With dewatering, the moisture content in the solids can be further reduced.
6.Resource utilization.
Coal washing wastewater contains a large number of useful substances, such as coal slime, heavy metals, etc. After treatment, these useful substances can be utilized. For example, coal slime can be used to make building materials, burn power generation, etc.; Heavy metals can be reused or further treated. Through the use of useful substances, not only can the discharge of waste be reduced, but also the recycling of resources can be realized.
Second, the application and advantages of coal washing wastewater filter press treatment technology.
Coal washing wastewater filter press treatment technology has been widely used at home and abroad, and its advantages are as follows:
1.High treatment efficiency: The filter press treatment technology can effectively remove harmful substances in coal washing wastewater, such as suspended solids, heavy metals and acidic substances, etc., and the treatment efficiency is high.
2.Resource utilization: Through the utilization of useful substances in coal washing wastewater, it can not only reduce the discharge of waste, but also realize the recycling of resources, which has significant environmental and economic benefits.
3.Strong adaptability: The filter press treatment technology has strong adaptability, which can treat coal washing wastewater of different properties and meet different treatment requirements.