Is there really no solution for high-salt, high-COD wastewater?
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When working on this project, I encountered wastewater with high salt levels (7%) and a high COD value of 20,000. The solvents present in the water can have an adverse effect on the membranes. Evaporation as a treatment method is too costly to be feasible. Additionally, there is 100 ppm of chloroform in the wastewater; combined with the high salt levels, this leads to toxicity in the biological treatment processes. There’s really no solution to this problem…… it’s frustrating
You can either opt for evaporation or cultivate salt-tolerant bacteria; it’s up to you to decide
Partial distillation is carried out, followed by back-dilution using the distilled water.
The usual approach is to first go through COD treatment (what’s used here is mainly ultraviolet light and phenol, though not really), then distill off some of the water to concentrate the salts (the best method for this purpose at present is MVR, although that’s not exactly the case either), and finally combine the mother liquor with the distilled water for further treatment (the most common method for this step these days is biochemical treatment, again, not entirely accurate)
As long as you’re willing to spend money, there is no water problem that can’t be solved. However, for this type of wastewater, there is truly no solution if one doesn’t want to spend money on treating it to meet the standards.
That is, if you don’t want to spend money, there’s no solution to anything
There has to be a limit to the cost too; it’s too expensive
It depends on the volume of water to be treated; if the amount is small, it can still be processed.
This post was last edited by Gorou’s Eight Trigrams Staff on 2015-8-24 at 10:19. The water in question is typical of high-salinity, high-COD wastewater; for such water, proper pre-treatment is essential when using evaporation or MVR methods, otherwise the evaporators will be damaged very quickly. We have used one type of evaporation equipment designed specifically for high-COD and high-salinity wastewater, and its treatment cost is moderate, though it is suitable only for small volumes of water. If it’s convenient for you, please provide information regarding the quality and volume of this water so that we can consider it. We can also send you some relevant materials via email; the investment required is moderate.
A salt content of 7% is already more than twice that of seawater. The COD value is 20,000 mg/L; the organic matter content is also high, and chloroform is present. It is practically impossible to treat this water using conventional biochemical methods, as the aquatic organisms have been completely dried up by the salt. If this water is to be treated biologically, it must first be desalinated. When the water volume is small, there are more options available. If the water volume is large and the budget for investment is limited, then this production process needs to be re-evaluated. It is necessary to take into account the cost implications of various aspects such as production, raw materials, products, water usage, water treatment, and environmental protection. This is not something that the original poster needs to consider or address; it falls within the responsibility of the company’s management and board of directors.
With such high salt levels, no bacteria can survive. With pure sodium chloride, some solutions might be possible, but with mixed salts… it’s frustrating. The main goal is to reduce COD levels, and it seems like there’s no solution to this problem; many industries face this issue! Looking forward to a breakthrough!