Design of Sludge Pit and Oil Recovery Tank

@Tiang Hock Lee Unfortunately we can’t quantify that as our cooling pond has been producing sludge oil of more than >1000 tons per year since few years ago. We have never been able to clear the oil in the cooling pond.

@Tiang Hock Lee We do not have an actual figure for that. But, over the 3 yrs average, my estimate is about 6.25 MT sludge per 1000MT FFB processed. But nonetheless, I would highly appreciate if you could comment on the RT of our inground sludge pit and the VC used for recovery. Thanks

@Wesley 6.25 tons of Sludge Oil (SO) per 1000 tons FFB processed is unusually high. The range reported by mills is between 1 and 3 tons SO per 1000 tons FFB processed. The industry practice for retention time (RT) in Vertical Clarifier ranges between 4-6 hours. That's for Crude Oil, not Waste Sludge from the Separators or Decanters. I suggest you check and monitor the oil entering your Sludge Pit:

1. Monitored and measured oil in Waste Sludge before the Sludge Pit from Separators and Decanters.

2. Unmonitored and unmeasured oil entering the Sludge Pit e.g. overflows from Crude Oil Tank, Sludge Tanks, Sludge Cyclones, etc. Provide traps to recovery oil from such spillage and look into how to prevent such spillage.

3. Oil content of underflow Waste Sludge from the Vertical Clarifier.

4. Operational issues like constant removal of sand and debris from the Sludge Pit and Vertical Clarifier to ensure maximum RT as all times.