Sewage sulfate
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At the wastewater treatment plant, the concentration was 200 mg/l before treatment and 650 mg/l after treatment; why is the concentration higher after treatment than before?
There are many factors that affect wastewater treatment, which lead to significant variations in test results and poor repeatability. However, in cases like the one described by the poster, it is possible to conduct multiple tests to assess the repeatability of the results. If there are no issues, then it is necessary to consider whether the coagulants and flocculants used in the treatment process contain sulfate compounds.
It may be caused by the oxidation of certain sulfides and sulfites. This post was last edited by johncom on 2009-3-30 08:10]
There is a difference between instantaneous values and average values; this helps to detect any abnormal emissions. Either it has been incorporated into the backend, and the wastewater from anion bed regeneration contains sulfate ions. It is also necessary to check whether there were substances in the wastewater before treatment that interfered with the measurement of sulfate; after treatment, these interfering substances were degraded, and the actual value of sulfate could be determined.
The amounts of coagulants and flocculants added are generally not very large, so it’s unlikely that the treated water level will rise by that much, right?
What is the water quality like, and what is the treatment process?
This is normal; it is most likely produced as a result of the oxidative decomposition of organic sulfides.
On the one hand, the presence of interfering substances may cause these substances to disappear before and after treatment, thereby eliminating the interference effect； On the other hand, do flocculants contain sulfate groups, such as aluminum sulfate or polyaluminum chlorosulfate? ； Furthermore, is there any issue with the sulfate determination method you are using? We previously used barium chloride for this purpose, and it was inaccurate many times over!
Our company used to purchase zinc salts, and everything was fine at first; later on, monitoring was neglected. When we realized something was wrong, we checked one side and found that there was no zinc there at all! We can’t believe ourselves anymore! Have you heard of adding other things to PAC? Hehe, it’s better to be careful!