Is it feasible to discharge after neutralizing alkaline solids and acidic waste liquids?
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During our company’s production process, a certain amount of alkaline solid waste is generated, which is removed using plate and frame filter presses. The main component of this waste is calcium carbonate, and at present it can only be stored in open-air waste dumps. There is another processing step that generates wastewater with a high acidity level, with salt content and acidity around 3%. Currently, this wastewater is neutralized using NaOH before being discharged to the plant’s wastewater treatment system; nearly 10 tons of NaOH are used each day (worth around 5,000 yuan, which is a significant amount over the course of a year). Now, there is an idea to add alkaline calcium carbonate to the acidic wastewater, stir it thoroughly to ensure proper reaction, and then use NaOH to neutralize any remaining acidity. If solid waste is formed, it can be filtered out in order to reduce the amount of NaOH needed. I’m not sure if this approach is feasible. Can wastewater with a high calcium content still be discharged into the wastewater treatment system? I would appreciate your advice.
Our company handles waste acid water in the same way; after neutralization, the wastewater turns black, which is quite troublesome.
It shouldn’t be possible, because there’s also the total salt content to consider; the limit is 1500, and it will definitely exceed that value. I’m not sure if you follow those discharge standards
You can give it a try to see how it works.
Good idea. However, after adding basic calcium carbonate, the pH is neutralized, but the solids that have been added to the water still need to be removed; it’s not clear whether this results in cost savings compared to before. It is recommended to conduct a pilot test first
It ultimately depends on you – whether the water quality meets the standards after neutralization, and what the treatment costs for the sludge generated are
It should be possible; check with the park’s wastewater treatment plant to find out the standards for acceptable wastewater. After adjustment in the neutralization tank, an additional sedimentation tank is added; the discharge is carried out with a pH value maintained between 6.8 and 9. If the waste sludge from the sedimentation tank contains no heavy metals or harmful elements, it can be treated as solid waste.