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Monitoring waste water COD/TOC/load

Monitoring waste water COD/TOC/load

Monitoring waste water COD/TOC/load

In our plant we have a wastewater tank. At the outlet of this tank, TOC is measured. When TOC exceeds certain value, there is an alarm in the control room. The operators are expected to find the root cause of the high load. However, there are multiple inlets (from different unit operations) to this tank. Thus, operators have to take a sample from each inlet to find out the root cause of this high load. This is a very time consuming process and often we are too late.
I want to place some measurements at the inlet sources. However, TOC house is too far away and expensive.
Are there other alternative ways to TOC or COD detection (does not have to be accurate-just AN indication) that can give me an indication?
I thought about conductivity;however, operations found it too susceptible to fouling. What are the cheap alternatives to detect such load?
We are producing yeast.

RE: Monitoring waste water COD/TOC/load

Would any of the TOC contributors be detectable by a pH instrument?

RE: Monitoring waste water COD/TOC/load

Or some other ion specific probe? They make dozens of different ones.
They are similar to pH probes but they respond to things other than H ions.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Monitoring waste water COD/TOC/load

1. Are you controlling TOC upstream with some chemical or process? - If you are controlling TOC with something like Chlorine, you can just measure the chlorine content and then infer TOC (most likely you'll be measuring residual Chlorine, this is done in Cooling Tower systems to keep down TOC and bacteria growth).

2. TOC can come from all the inlets upstream to your wastewater tank, but which sources upstream contribute the most to total TOC or which is most likely to have TOC increase? - If you can identify this you can cost-effectively only add continuous monitoring to that stream.

3. Chemical Vendors can provide you with a very expensive continuous monitoring system that essentially recycles a split stream through the system and monitors with their probes. People like GE, Chemtreat, or Nalco would have a very expensive option for you if you believe it is worth it.

You may be better off measuring variables upstream tighter and setting alarms based on upstream values instead of TOC. In my experience once you took TOC it would be too late, so I would set parameters tighter upstream to ensure that TOC doesn't get out of hand.

I hope this helps and good luck!

Laron B.
Results. Not Recommendations
Sr. Chemical Engineer

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