Clear water influent to sand filter, yellow water effluent

[chemebabak]

How is that possible?

We separate water and crude oil from the oil wells. The separated water enters the clarifier with ~150 ppm oil and visible suspended solids. The water from the clarifier is clear color, no SS and 0 ppm oil.

The water then passes through the sand filter and turns yellow. We had a process upset which may have contaminated the filter. I do not think it is channelling in the filter.

Does anyone have any thoughts or suggestions as to why the water turns yellow?

 

[bimr]

You do not list much as to the process parameters. One would suspect that a dissolved material such as iron may be oxidizing and precipitating from solution.

Should be easy to have a lab test done.