My cooling pond where I am currently using a submersible pump to recover sludge oil came to some difficulties due to the amount of thick scum/foam on the surface blocking the oil. How did it come about and how to rectify it?
some say maybe because of claybath waste? Should i divert it to anarobic pond?


Apparently your pond is too big. You may have to look at the oil losses from processing and the sludge oil recovery such as Sludge pit and Recovery Oil tank system to ensure minimum oil loss to this cooling pond.
Looks like your ponds are getting to be active. Normally cooling and acidification ponds should be kept small for 2-3 days retention time. This is to maintain high temperature for recovery of oil. The scum layer will appear when there is a high percentage of oil in the influent and anaerobic activity. Make sure you are not recycling activated sludge from the anaerobic ponds into the Cooling Ponds. It is a good idea to have a settling pit for removal of spend kaolin clay before pumping the waste to the POME Treatment Plant. It is good idea to bypass the Waste Kaolin from the Cooling Pond.