Seeking good methods for phosphorus removal in terminals
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For light chemical industry wastewater, the phosphorus concentration in the water after A2O treatment is 10 ppm; after flocculation using PAC+PAM, this concentration rises to 7.7 ppm (with a COD of 53, SS of 15, and pH of 6.8). The required level is 1 ppm! What should be done regarding water-soluble orthophosphates? Are there any other good ways besides adding water? Thank you
This type of wastewater can be fully used as makeup water for circulating water, enabling the system to eliminate waste discharge. There’s no need for further dephosphorization treatment – isn’t that good?
Based on your data, it seems that the amount of PAC added is not sufficient. Conduct experiments in the laboratory to see if increasing the amount of PAC added will help in removing phosphorus； Additionally, aluminum phosphates have the lowest solubility at pH 6–7; please pay attention to controlling the pH value ；
You are making great efforts to promote your zero-emission concept, and I admire as well as respect your professional attitude. However, I hope you will conduct an analysis of the specific water quality, provide some convincing data, and offer a scientific analysis and recommendations aimed at helping the property owners solve their problems. This approach would be much better than your current general promotional efforts; moreover, excessive promotion can lead to resentment, which would put you in a more disadvantageous position. Based on the quality of this water, it is feasible to use it as make-up water for circulating water; at most, a sand filter or a combination of a sand filter and a carbon filter can be added. Moreover, the presence of phosphorus reduces the amount of corrosion and scale inhibition agents required.
Agree with the suggestion from the 3rd floor: \"Based on your data, it seems that the amount of PAC added is not sufficient. Conduct experiments in the laboratory to see if increasing the amount of PAC added helps in removing phosphorus.\"； Additionally, aluminum phosphates have the lowest solubility at pH 6–7; please pay attention to controlling the pH value ； ” If the emission requirements cannot be met, two-stage phosphorus removal may be necessary, using both pre-precipitation and post-precipitation methods ； Another point to note is the need to determine whether it is all orthophosphates; if it are phosphites, metaphosphates, or pyrophosphates, things become more complicated, as conventional metal precipitation methods cannot remove phosphate ions.
If chemical phosphorus removal is considered for the tail water, to reduce the phosphorus level from 10 ppm to 1 ppm, a considerable amount of PAC needs to be added.
Aluminum, iron, along with lime, can also be considered for removal; using these two together allows for the control of pH levels, thereby avoiding the drawback of low pH resulting from the use of aluminum and iron for phosphorus removal, as well as high pH levels caused by the use of lime for phosphorus removal.
Thank you for the reminder. Whether our technology can be applied to certain types of wastewater can only be determined through tests on water samples; we cannot draw any conclusions based solely on water quality data.
May I ask: To what minimum level in ppm can total phosphorus be reduced using aluminum or iron salt coagulants? What pH value is generally most effective for achieving this?
Some comrades these days are really amazing – they don’t even check the water quality; they just achieve zero emissions! It’s just like those sellers of miracle medicines in ancient times, who claimed to be able to cure any disease! If it’s really that great, why not just withdraw from the water treatment industry and let your family handle it instead? Some advice for certain people: stop doing promotions here; it would be better to use that time to approach the **Environmental Protection Agency – after all, these are global problems that need to be solved by them. It would be great if the Environmental Protection Agency helped you with promotion – it’s a win-win situation: **the EPA achieves its goals, and you get more market access!**
The solubility is lowest at the following pH values: ferric phosphate: 5–6； Aluminum phosphate: 6-7 ； Calcium phosphate: greater than 8.5. The amount added is the number of moles removed.