Treatment of high COD wastewater with high salt content
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Main components of the wastewater: 15% sodium chloride, 0.5% sodium thiocyanate, 0.5% dichloropropene, 0.2% 3-thiocyanato-1-propene； The wastewater volume is approximately 30 tons per day ； What are some good treatment processes available for COD levels around 10,000?
The main issue is desalination; the COD problem is not that serious. Desalination and distillation are possible but costly; reverse osmosis is an option as well but requires significant investment in equipment. Are there any other methods? In any case, it’s difficult to implement. Is considering adding other substances to make it precipitate?
This is a type of wastewater that is very difficult to handle. 1. The sodium chloride content is very high, exceeding that of seawater by more than 5 times; aside from COD, direct biological treatment is difficult, if not practically impossible. We need to consider how to desalt it. 2. Dichloropropene is a chlorinated organic compound that is difficult to degrade. Additionally, thiocyanatopropene is a raw material used in the synthesis of mesityl oil; it has a strong, irritating odor, and handling it in an open environment is not advisable. It is recommended that the poster first find a professional water treatment company to conduct a pilot test, before deciding on the process to be used.
Reverse osmosis? Impossible. The most trendy MVRs these days; it is said that there are also companies willing to handle such low throughput. We who are not MVRs can only watch with envy and resentment.
Cyanide can be broken down first, followed by evaporation for desalination, and the evaporated liquid is then regenerated.
Go straight to evaporation, MVR evaporation treatment. It is more energy-efficient; if there is an ample supply of steam in your area, you can consider a three-effect falling-film evaporator.
Multi-effect evaporation, or MVR: Multi-effect evaporation has higher operating costs, but lower initial investment; MVR has lower operating costs, yet a higher initial investment. A production volume of 30 tons per day is not very large, so the equipment investment will also be significant But whether pre-treatment is needed can only be determined after the manufacturer conducts experiments for you!
For the evaporation-based heating MVR system, it is necessary to first conduct another analysis of the components in the wastewater; only after confirming through experiments that the wastewater can be properly treated should this system be put into use
First, remove cyanide to eliminate most of the low-boiling-point organic compounds; then use an evaporator, and after that, just carry out some biochemical treatment and it’s done!
First, the salt must be removed; high salt levels make it difficult for microorganisms to handle the substance. We use triple-effect evaporation, which results in high operating costs
Have you considered using membrane treatment, as the salt content is quite high?