Treatment process for high COD and high salt wastewater

Calcium-aluminum compounds can be used to remove sulfates. For high COD, refer to http://bbs.hcbbs.com/thread-208968-1-1.html

What are the main components of organic matter? Is there any value in recycling it? If there is a value in recycling it, then recycling can be considered; otherwise, the high-salt wastewater can be diluted with other low-salt wastewater and then treated through biological methods.

Extraction + adsorption + ultrafiltration + two-stage reverse osmosis + three-effect evaporation – this is a process I developed on my own; I would appreciate some guidance from experts.

The COD is very high; I wonder what organic substances are present in the wastewater? Can the original poster tell what type of process wastewater it is? It’s best to recycle if possible. Since the solubility of sodium sulfate varies significantly with temperature, multi-effect evaporation can be considered for its recovery.

The process involves the phenol-free pyrolysis of castor oil to produce sebacic acid; the wastewater originates mainly from the separation process of sebacic acid, and it contains organic substances such as sebacic acid and sebacates.

If the wastewater contains organic substances such as sebacic acid and sebates, physical extraction can be used; suitable solvents include MIBK, isobutyl ether, isopentyl acetate, and other non-reactive organic solvents with moderate polarity and relatively low boiling points (which facilitate the separation from sebacic acid, sebates, etc.). Furthermore, techniques such as stripping must be used to further recover the extractant with a certain solubility from the wastewater. It is estimated that the pH value needs to be lowered further before extraction. Reverse osmosis is not an option; with a 6% concentration of divalent salts, the operating pressure needs to be above 100 atm. Also, due to the property of sodium sulfate’s solubility changing with temperature, freezing crystallization is likely not feasible with such a large amount of water. If sodium sulfate has a market, six-effect evaporation should be considered; three-effect evaporation requires too much energy, unless there is an inexpensive heat source available. In fact, the ideal treatment for this wastewater is as follows: 1. Select an appropriate extractant; through physical extraction and distillation to regenerate the extractant, sebacic acid and sebestic acid by-products are obtained. 2. Microfiltration and ultrafiltration are used to remove suspended solids and oil droplets. 3. The dissolved extractant is recovered via distillation, yielding an azeotrope of water and the extractant which is then returned to the extraction tower. 4. Membrane-based multi-stage multi-effect evaporation is used to concentrate sodium sulfate from 6–7% to 25%. 5. Conventional triple-effect evaporation is employed for evaporation-crystallization to produce gypsum. Good meta-nitrate can be purchased at 900 yuan per ton. By doing this, both investment and operational costs are minimized. The combination of steps 2 and 3 ensures complete recovery of sebacic acid and sebic acid esters, while also maintaining the stability of the membrane used in step 4. Step 5 requires 130–150 degrees of steam, and the secondary steam generated can be used for Step 4, which does not need to consume any additional high-quality heat energy. Alternatively, both can use a low-temperature heat source of 80-100 degrees. Therefore, the operation designed as above is extremely energy-efficient. Of course, if the wastewater containing sodium sulfate can be discharged directly, then only step 3 of wastewater treatment is necessary. We can carry out extractant screening, as well as the design, construction, installation, and commissioning of extraction towers ； Stirrer tower design, construction, installation, and commissioning ； Design, construction, installation, and commissioning of membrane-based multi-stage multi-effect evaporation ； As well as the design and selection of multi-effect evaporators. Of course, this project has a somewhat research and development nature. I don’t know if the industry is large or not. For interest, please contact yjqin1@yahoo.com or yqin@chembrane.com

I would like to ask again: 1. Is it possible to use ricinoleic acid as the extractant? This way, the extract phase can be returned directly to the production system, eliminating the need for back-extraction.

Of course, this is better as it combines the original process. But in that case, it’s only possible to go directly from step one to step five (using six-effect evaporation rather than three-effect), provided there is an excess of steam available in the plant. Furthermore, castor oil acid is relatively expensive; generally, there is an emulsification loss of 200–1000 ppm in the raffinate phase, which needs to be recovered.

What is the distribution coefficient of sebacic acid in the ricinoleic acid-water system? Greater than 10; 50 would be even better. Last edited by yjqin1 on 2009-3-22 08:48.]

First, analyze what the components of high COD are; if they are mainly oxidizable inorganic salts, chemical methods such as crystallization and salting out can be employed! ! !

At this salinity, biochemical treatment is also possible after recovery

When determining the process, consider carefully whether it is necessary and what requirements the manufacturer has.

Phenol is used as a cracking agent in the production of sebacic acid, and the wastewater contains approximately 2500 mg/L of phenol, sebacic acid, and sulfates. The challenge in treating this water is that sebacic acid dissolved in the wastewater keeps precipitating as the temperature of the wastewater changes, and it is difficult to remove it using simple filtration processes; phenol, on the other hand, can be removed through resin adsorption. Currently, some companies in the country use ricinoleic acid extraction, but there is significant loss of ricinoleic acid, and re-cracking affects the quality and yield; this extraction method is only used to meet environmental regulations and is not employed on a regular basis. Using evaporation, since phenol volatilizes along with water vapor, the effluent still needs to have its phenol content removed. Domestic sebacic acid manufacturers use our resin to absorb phenol from wastewater, but they employ their own methods for removing sebacic acid. At the moment, we are considering using resin to recover sebacic acid, and then using resin again to recover phenol. If you agree, I can arrange for technicians to go to your site to conduct experiments. Contact: 13991330291, gfmin@sina.com

LZ, if the volume of water is not very large, incineration can be considered, as it is a simpler method for treatment.

Under high COD conditions, the amount of adsorbent required for this process will be enormous!

I think multi-stage nanofiltration for two-way concentration could be considered; to prevent organic substances from adhering to the nanofiltration membrane during concentration, synchronous dilution technology can be used to address this issue!

Ricin oil pyrolysis employs a phenol-free pyrolysis process; therefore, the wastewater contains no phenol, but mainly sebacic acid, sebacate, and sodium sulfate. Extraction + adsorption + ultrafiltration + reverse osmosis + falling film evaporator are used to achieve zero wastewater discharge. Is this feasible, everyone?

What if the main component is resin? It’s mainly liquid resin wastewater and o-cresol resin wastewater

To what level needs your COD to be reduced, and to what level needs the sodium sulfate level to be reduced? Are there any other organic substances in the water? Our company is capable of treating such water; feel free to contact me at 15088793370 if needed