On the treatment technologies for organic wastewater containing alcohols and aldehydes from chemical plants
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I would like to ask fellow professionals in this field: Our company currently has a facility that generates organic wastewater containing alcohols, aldehydes, etc., at a rate of about 15 tons per hour; the COD level of this wastewater is around 50,000 mg/l. I’m wondering whether the use of activated carbon adsorption can reduce the COD level to below 4,000 mg/l. Alternatively, I’m curious if simple distillation or stripping processes could achieve this goal. What are the costs associated with each of these processing methods? Using biochemical methods previously had no effect. Isooctanol, etc.; boiling range of polyols: 100–300 degrees; pH: 3–4
Consider using adsorption resins for adsorption, followed by desorption through a certain method. Activated carbon should also be able to achieve values below 4000, but it is difficult to regenerate, resulting in high operating costs. gfmin@sina.com
“pH: 3–4; carboxylic acids may also be present in the wastewater. Simple distillation and stripping processes cannot effectively remove polyols, carboxylic acids, and formaldehyde. Adsorbents that can effectively adsorb weakly polar organic compounds such as isobutanol cannot effectively adsorb formaldehyde, polyols, or low-carbon carboxylic acids such as formic acid, acetic acid, and propionic acid.
Firstly, using activated carbon for adsorption can certainly achieve this effect, as the adsorption capacity of activated carbon can be increased significantly by adding more of it or replacing it, which allows the COD level to be brought within acceptable limits. However, this approach is too costly. We all know that activated carbon has a certain adsorption capacity; once it reaches saturation, it becomes useless, and at that point it is necessary to replace it – either with new activated carbon or with regenerated activated carbon. The cost of regenerating activated carbon is high, and the initial investment required is significant, which makes it somewhat uneconomical in such cases. It is somewhat difficult to use direct biochemical treatment for such wastewater due to the high COD level. But it should be fine to carry out pretreatment before applying biochemical methods; with a pH of 3-4, using microelectrolysis for pretreatment can not only **reduce COD but also improve biodegradability. After that, anaerobic biochemical treatment can be carried out, followed by secondary contact oxidation for aerobic biochemical treatment – this approach should present no major issues. It’s also possible to burn it directly, but the cost might be relatively high.