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Reduce COD level


We are ISO 14000 certified Company, Business relate to manufacturing of the surgical instruments. we are facing COD level limit that is very excessive from the optimum range of NEQS. noted range of the COD level 440 whereas required 150 in the waste water.
water Consumption range is 9000 gallon on daily bases.

We are kin interested to get solution for COD reduction and we hope your suggest will be beneficial for us.

Used chemical: sulfuric acid, Phosphoric acid, Glycerine, Nitric acid, Tricholoethylene

waiting your reply

Imran Goraya
QA Manager

M. Imran Goraya
- Sialkot, Punjab, Pakistan


Do a search for COD and BOD at this site as it has been discussed before.
No one can tell without seeing your operation.
My guess would be from oil or from the trike that is trapped (cupped) in the part.

James Watts
- Navarre, Florida


Dear M. Goraya

I'm afraid the information you give is very very limited and it is not possible to give directly useful suggestions.

COD measures the amount of organic material in waste water. So from your list, glycerine is a good candidate. Trichloroethylene has a high COD, but should NEVER end up in the waste water.
Other good candidates are :
- soap and water-based cleaners
- facilities for workers (kitchen, toilets, showers, ...)
- oil and emulsions e.g. from metal-working fluids

First step is to make a scheme or a list with al the individual sources of waste water in your plant.

Second step is to find out for each waste water stream if it has a high content of organic material or not. This can be done by
- measurements (COD, BOD, TOC)
- common sense (any organic material in this stream ?)

Third step is to check if it is possible to avoid the few substreams with high COD. This is not always possible, but if it is possible, this is by far the easiest and cheapest solution. Avoiding could be done by small modifications in the production methods (e.g. modification of a chemical product that is used) or by cheap treatment steps (e.g. oil skimmer)

Last step (if still needed) is to plan a waste water treatment on the right substreams. No need to build a big treatment station and to treat all the rinsing waters having a low COD and BOD. Treat only relevant streams in a small and efficient treatment station.


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