Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
-----
Ideas on how to cool wastewater and ways to reduce COD
Q. I am researching ways to do a couple of things;
First- I need to reduce process water from about 110 degrees Fahrenheit(maximum temperature) to about 75 to 80 degrees Fahrenheit. The water line is pressurized and the flow is 500 gallons per minute(GPM) with a maximum of 700 GPM. We are in the process of reducing that flow to below 400 GPM. More information available upon request.
Second - I need a low cost way to reduce COD levels. currently we are running at about 4000-5000(mg/l) on the high end of production. And about 2500-3500(mg/l) on the low end. We are doing what we can in the processing plant. I am looking for suggestions/ideas for the treatment end.
Thanks!
Gregory J. Dayleypotato processing plant - Firth, Idaho
2003
A. A cooling tower could easily cool this, but if you can't expose it to the atmosphere an evaporative condenser is very inexpensive to operate. The COD is a much bigger problem, probably requiring a trickling filter or activated sludge pond.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003
A. We have had excellent luck in plants of your type using microbial enzymes to eat the waste. It is a nice clean operation with the byproducts being carbon Dioxide, water and a little sludge.
Edward Petermann- Kitchener, Ontario, Canada
2003
A. This may become too complex to be practical, but is it possible to re-route the water line through a cold water rinse tank (the cold water would act as the heat sink) or maybe a tank that needs a little heat, that could benefit from the hotter water passing through?
Dan Brewerchemical process supplier - Gurnee, Illinois
2003
Q. I would like to follow-up the similar question on how to reduce the COD. Is there any practical ways ? What affects the COD ? Is temperature a factor ? What about oil content (crude oil)? Thanks for the information
Johar [last name deleted for privacy by Editor]- Indonesia
2004
2004
COD is Chemical Oxygen Demand. I don't remember the exact distinction between this and BOD (Biological Oxygen Demand) without going back and looking it up (my wastewater experience has been pretty much restricted to inorganic metal finishing wastes, which have little COD or BOD). But the principal is that you should not discharge waste water to the environment which would consume a great deal of oxygen to make itself right. Instead you should first subject it to a treatment which will oxidize such materials. A trickling filter, a highly oxygenated treatment pond, etc.
Temperature could possibly distort a COD reading, but it is not part of what constitutes COD; but I think oil would be.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. How to reduce the cod from 4000 - 4500ppm to 100 - 150 ppm.
For reducing the cod what kind of chemicals to be used and the list of suppliers in India.
employee - Tamilnadu, India
August 12, 2008
A. According to my experience to reduce the COD we can use Aluminium sulphate and Polymer and then DAF system which effectively reduce the amount of COD with the introduction of Air mixed with water to the DAF inlet......
Amjed Ghafoor- Pakistan
April 19, 2011
A. In industries, where the daily water consumption is very high, generally they have an ETP (Effluent Treatment Plant) which has a few systems and finally the treated water comes out which has a COD of about 200ppm (initially it may have a COD of 4000 ppm). So, for that level of decrement you need to have an ETP otherwise its like very difficult to bring COD from 4000 to 200.
You can read what an ETP does and the different systems in it on wiki or google it out.
- IIT Kharagpur, India
May 29, 2011
Q. Can Enzyme lower a COD of 286 to acceptable limit of 100 without the use of aeration? We have a problem with our septic tank.
Thanks
- National Capital Region, Philippines
March 15, 2012
Q, A, or Comment on THIS thread -or- Start a NEW Thread