Are Effluent Treatment Plant required in coal producing facilities?
To compensate for our country's lack of energy structure, projects involving the use of coal to produce oil, natural gas, and other chemical materials have been sprouting up around the country. A huge volume of wastewater is created throughout the combustion, gasification, cooling, and washing processes. The makeup of the wastewater is quite complex. Coal chemical wastewater is not only connected to coal quality, but it is also strongly tied to the gasification process. The coal chemical wastewater is typical industrial wastewater that is difficult to degrade due to the presence of organic contaminants such as phenols, polycyclic aromatic hydrocarbons, and heterocyclic nitrogen and sulphur compounds.
What is the basic process of wastewater treatment in coal industry?
The biochemical approach is the most often used method for treating coal chemical effluent. It has good effects on the removal of phenol and benzene compounds, but it has poor effects on the removal of quinolone, indole, pyridine, carbazole, and certain refractory organic materials. Emission regulations for COD of wastewater are challenging to meet.
In our nation, phenol ammonia recovery and wastewater treatment technologies are employed to treat gas water produced by pulverized coal gasification. The breakdown of organic matter in coal is incomplete due to the low gasification operating temperature, and the difficulty is that the gas water is big and complicated in composition.
Despite the use of treatments, reaching the discharge criteria for wastewater is still a challenging task. Volatile phenols and other problems remain throughout the treatment procedure. The wastewater treatment procedure is lengthy and varies widely between building sites. The stability of therapy impact has to be confirmed.
The primary purpose of biological treatment, such as acidification, hydrolysis, A/O process, SBR process, and so on, is to remove COD, increase biodegradability, and remove nitrogen. Coagulation, filtration, ozone, biological aerated filter (BAF), and activated carbon (coke) adsorption, as well as their combination, are used in a three-stage treatment procedure. In the desalting treatment procedure, membrane separation technology such as UF, RO, and so on is employed.
Three stages of treatment process
1: Pre-treatment process
Pre-treatment is used to eliminate contaminants that cannot be removed by biochemistry but can interfere with biochemical treatment. The emphasis of pre-treatment is oil. The oily wastewater is separated using a combination of horizontal flow separation, inclined plate oil separation, and air flotation.
Recently, several complex equipment’s for treating oily wastewater have been developed, such as a regulating tank, an oil-water separator, an air flotation device, and so on. The primary pre-treatment procedure was created using advanced equipment. The removal of emulsified oil, dissolved oil and subdivision oil needs use of medicines and even multi-stage flotation.
2: Biochemical treatment process
There are several biochemical therapy methods. Oxidation ditch, SBR, A/O, common activated sludge process, and MBR are examples of conventional activated sludge treatment procedures.
The biological membrane process consists mostly of the contact oxidation process and the BAF process. Each treatment procedure has its own properties and is appropriate for different types of water. Coal chemical wastewater with a high COD content is classified as high concentration sewage. The biochemical method used to treat coal chemical wastewater should increase biochemical performance and nitrogen removal efficiency, and it should be favourable to long-term stable operation and convenient operation.
3: Secondary wastewater treatment processes
Secondary biochemicals contain trace amounts of ammonia, nitrogen, and organic compounds that do not exceed discharge criteria or water requirements. Sewage can be released to fulfil local discharge limits and overall pollution control needs. Tertiary treatment methods include biological aerated filters (BAFs), contact oxidation, filtration, ozonation, biological carbon/activated carbon, disinfection, membrane treatment, biological oxidation ponds, and other combination processes.
All such technologies are employed by Netsol Water in various industrial and commercial sectors.