Sulfuric acid wastewater treatment
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Our plant’s 120kt/a sulfuric acid wastewater is currently treated using a process that involves adding lime followed by sedimentation; the water is discharged outside the plant without being reused. We are now considering a system for fully closed-loop recycling of this wastewater. In place of electrostatic precipitation, we plan to use a venturi tube + foam tower + electrostatic demisting system. For wastewater treatment, we will employ high-efficiency filters + plate heat exchangers + cooling towers. Our factory is working with a manufacturer to develop a new type of filter that allows wastewater to be filtered directly without the need to add any flocculants. We have used this manufacturer’s smaller devices in the past, and their performance was excellent. I would appreciate any insights you might have
Lime is used for neutralizing sulfuric acid wastewater, and treatment is not a problem; however, a considerable amount of sludge is generated, leading to significant waste of lime. Moreover, the calcium sulfate formed is slightly soluble in water, which can cause clogging in filters. It’s better to use a sedimentation tank later.
Reusing diluted acid after filtration leads to F enrichment, which damages the catalyst
If direct filtration is used, it’s important to control the turbidity of the water coming from the pre-treatment sedimentation stage; otherwise, the filter won’t operate properly – issues such as clogging of the filter media and frequent backwashing may occur. :)
What is the quality of sulfuric acid wastewater like? Does it contain sulfuric acid and phosphoric acid? Contains arsenic or other heavy metals? What is the initial turbidity of the sulfuric acid wastewater? What is the acid content of this wastewater? Is adding lime just to neutralize sulfuric acid? I am looking for application areas for an efficient and energy-saving concentration technology using dilute sulfuric acid membranes that I have developed. I have consulted the experts! Thank you!
Another point is that since sulfate ions are not easy to remove, if the concentration of sulfate ions in the treated water is high, it is not suitable for use as cooling water. The reason is that sulfate ions cause significant corrosion to equipment; even after adding zinc ions, the rate of corrosion remains quite high. Therefore, when considering reusing such wastewater, the ion concentration must be taken into account.
Does SO42- mentioned upstairs cause significant corrosion to equipment? Sulfate ions don’t seem to cause direct corrosion; they are scaling ions, and scaling leads to corrosion beneath the scale.
In our factory, the water used for washing and purifying in the electroplating process is subjected to a closed-loop system; lime is used for neutralization, and sedimentation tanks are employed for separation. These tanks are cleaned regularly, and the sediment is sold to cement factories as filler, which constitutes a form of waste utilization.
Our factory also uses the lime-iron salt method for treatment, but the calcium content in the water after treatment reaches 2000–3000 mg/L. It tends to scale very easily. Please have the original poster take a look. This post was last edited by li*ch1968 on 2009-4-25 07:58.]
The last edit to this post was made by li*ch1968 on 2009-5-16 at 19:26. You can simply add a sedimentation tank, or you can consult a design firm; based on the specifications you require, it’s theoretically possible to include a sedimentation tank in your system
The calcium sulfate particles formed when sulfuric acid is neutralized with lime water are very fine; the more efficient the filter, the easier it is for it to get clogged. It is therefore advisable to use a sedimentation tank.
Consider using Digia membrane filters.
Filtering devices should be used with caution to avoid future problems; using lime for neutralization in a sedimentation tank should suffice