Is a pH level of 9–10 the most suitable for brackish water?
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This post was last edited by sunjl1981 on 2013-1-6 at 22:40, in order to maintain the reducing property of sodium hydride while reducing the consumption of alkali used in the process -
It is generally kept around 8.5 to 9
If less alkali is added, more sodium hypochlorite has to be used. It’s up to you to control this aspect, ensuring that there is no free chlorine present
Reply to 3# flay0303: I want to know right now how much would be the best option – something that is both economical and practical
Our factory’s range is 9.5 to 10.5. As for the exact value, it depends on whether there is little free chlorine present, and analysis plays a key role in determining it; sometimes more may be needed and other times less.
It depends on the specific situation: if the amount of slightly salty water to be treated is large, set the value lower (8.5–9); if the amount is small, set it higher (10–11). Also, if the previous parameters are well controlled, keep the pH a bit lower (8.5~9). In our unit, there have been instances where the pH level suddenly dropped to around 3. Since the flow rate of the brackish water is very low, and the pH is kept at 8–9, even slight fluctuations in the preceding parameters can cause a sudden drop in pH, such as fluctuations in the acid flow rate or changes in the brackish water flow rate. In short, sodium sulfite can effectively remove free chlorine under alkaline conditions; if the solution is stable, there is no need to add too much alkali.
It should be sufficient as long as the free chlorine level is 0