With the deepening of coal mining, the generation of coal mine wastewater is also increasing. This wastewater mainly comes from mine drainage, coal washing, open-pit pit and other links, and contains a large amount of suspended solids, heavy metals, acidic substances and harmful chemicals, etc., which has a serious impact on the environment and ecology. Therefore, it is necessary to treat coal mine wastewater. This paper will examine the treatment technology of coal mine wastewater.
1. Precipitation method.
Sedimentation method is a common method for treating coal mine wastewater, which mainly removes suspended solids and heavy metals and other substances in wastewater by physical means. The method includes two methods: natural precipitation and coagulation precipitation. The natural precipitation method uses the principle that the density of suspended solids is different from that of water, and makes the suspended solids settle naturally by standing still. Coagulation and sedimentation is done by adding coagulants to form flocs in suspended solids, which are then removed by sedimentation or filtration.
2. Chemical oxidation.
The chemical oxidation method is to oxidize the reducing substances in coal mine wastewater into harmless or low-toxicity substances through oxidants, so as to achieve the purpose of purifying and treating wastewater. Commonly used oxidants are ozone, chlorine, hypochlorite, etc. Chemical oxidation can not only remove reducing substances and organic matter in wastewater, but also kill bacteria and viruses, and has a good treatment effect.
3. Activated sludge method.
The activated sludge method is a biological treatment method that achieves the purpose of purifying wastewater by cultivating and domesticating activated sludge so that it has the ability to degrade organic matter. The activated sludge method has the advantages of good treatment effect and low cost, but it has high requirements for water quality and operating conditions, and it is necessary to strictly control the pH value and organic matter content of the influent water.
Fourth, the biofilm method.
The biofilm method is a biological treatment method similar to the activated sludge method, which degrades organic matter and purifies wastewater by cultivating and domesticating microorganisms in wastewater to form a layer of biofilm on the surface of the filler. The biofilm method has the advantages of strong resistance to shock load, good treatment effect and stable operation, but it needs to change the packing and clean the filter regularly.
5. Electrochemical method.
Electrochemical method is an emerging wastewater treatment technology that uses the principle of electrolysis to convert harmful substances in wastewater into harmless or low-toxicity substances. The electrochemical method has the advantages of good treatment effect, simple operation and small footprint, but the cost is high and the requirements for water quality are high.
6. Adsorption method.
The adsorption method uses the adsorption of adsorbents to remove harmful substances in wastewater. Commonly used adsorbents are activated carbon, zeolite, bentonite, etc. The adsorption method has the advantages of good treatment effect and simple operation, but the regeneration and replacement cost of adsorbent is high.
To sum up, there are many treatment technologies for coal mine wastewater, and it is crucial to choose the appropriate treatment method according to the nature and treatment requirements of the wastewater. In practical applications, a combination of methods can be used to achieve better treatment results. At the same time, the monitoring and control of the wastewater treatment process should be strengthened to ensure that the treatment effect is stable and reliable, and contribute to environmental protection and sustainable development.