Coking wastewater** is a variety of wastewater generated in the coking process, including wet desulfurization of coal, gas cooling, gas scrubbing, etc. These wastewater contain a large number of harmful substances, such as phenols, cyanides, sulfides, ammonia nitrogen and polycyclic aromatic hydrocarbons, etc., which will cause serious pollution to the environment if they are discharged directly without treatment. Therefore, the treatment of coking wastewater is particularly important. In recent years, with the development of membrane separation technology, reverse osmosis (RO) membrane technology has been widely used in the treatment of coking wastewater due to its efficient purification capacity.
1. Reverse osmosis membrane technology
Reverse osmosis membrane technology is a kind of selective permeation that uses the selective permeability of semi-permeable membranes to make the solvent (usually water) reverse permeate out of the solution by applying a pressure higher than the osmotic pressure of the solution, so as to achieve the purpose of removing solutes (such as salts, organic matter, etc.) in the solution. This technology can effectively remove particles, bacteria, viruses, heavy metal ions and most organic matter in water, is a physical process, does not involve chemical changes, and has the advantages of high efficiency, safety and environmental protection.
2. Coking wastewater
The main pollutants of coking wastewater include suspended solids, COD (chemical oxygen demand), BOD (biological oxygen demand), ammonia nitrogen, sulfide, phenols, cyanide, etc., the presence of these substances not only pollutes the water body, but also poses a threat to human health. Therefore, the treatment of coking wastewater requires the removal or reduction of the concentration of these harmful substances.
3. Three steps of reverse osmosis membrane technology in coking wastewater treatment
1.Pretreatment stage: In order to protect the reverse osmosis membrane from being polluted by suspended solids, macromolecular organic matter and grease, it is necessary to pretreat the coking wastewater. Pretreatment methods usually include pH adjustment, flocculation and sedimentation, filtration, etc., to remove suspended solids and some organic matter from the wastewater.
2.Reverse osmosis treatment stage: The pretreated wastewater enters the reverse osmosis system, and dissolved solids (such as salts), organic matter, bacteria, etc. in the water are removed through the reverse osmosis membrane. Reverse osmosis treatment can significantly improve water quality, and the resulting infiltration water can be directly reused or meet discharge standards.
3.Post-treatment stage: As needed, the reverse osmosis treated water can also be further refined through technologies such as ion exchange and depth filtration to meet specific water use standards or discharge standards.
4. Challenges and countermeasures
Reverse osmosis membrane technology has significant advantages in coking wastewater treatment, such as the ability to efficiently remove harmful substances from wastewater and provide high-purity water quality. However, there are still some challenges, such as membrane fouling and membrane material selection. In response to these challenges, the following countermeasures can be taken:
1.Optimize the pretreatment process: Reduce the burden of contamination on the reverse osmosis membrane by optimizing the pretreatment steps, such as improving the flocculation efficiency and selecting the appropriate filter material.
2.Membrane cleaning and replacement: Regular chemical cleaning of reverse osmosis membranes removes contaminants on the membrane surface and prolongs the service life of the membrane. At the same time, the membrane element is replaced in time according to the performance change of the membrane to ensure the processing efficiency of the system.
3.R&D of membrane materials: research and development of more pollution-resistant and efficient membrane materials to improve the stability and economy of reverse osmosis systems.
The application of reverse osmosis membrane technology in coking wastewater treatment provides an efficient and environmentally friendly solution. Through reasonable design and operation management, it can effectively remove harmful substances in wastewater, meet environmental protection discharge standards, and realize the recycling of water resources. In the future, with the progress of membrane material technology and the optimization of treatment process, the application of reverse osmosis membrane technology in the field of coking wastewater treatment will be more extensive and efficient.
The article was edited and shared by Dalton Membrane, **Please note the source!