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References: Palm Oil Mills



PALMAR SANTA ELENA
120 T of fruit per day - 5 T COD/day
Location: Tumaco, Colombia
These mills generate effluent with a high organic content (COD of the order of 50,000 mg/litre)

Palm Oil Mills usually treat this effluent in a serie of ponds: de-oiling, cooling, anaerobic, facultative, effluent polishing.

This system is relatively inexpensive in spite of the enormous volumes of earth to be moved and, when well designed, operated and maintained, is highly efficient in removing organic matter content, up to 99%.
However, this does require impermeable soil or the installation of geomembranes under the ponds.


PALMEIRAS
200 T of fruit per day - 10 T COD/day
Location: Tumaco, Colombia

The main disadvantages with currently operating systems are:

  • The need for large areas of land
  • Impractical oil collection methods
  • Contamination of the ground water
  • Ponds quickly fill with thick sludge
In addition to this, palm industry anaerobic ponds release enormous amounts of biogas (methane gas) into the atmosphere, which on the one hand is a wasted energy resource and on the other pollutes the atmosphere (greenhouse effect).

BIOTEC offers various types of services to palm oil mills (seePortfolio):


PALMEIRAS
Conversion of fuel engines (CAT 3408 - 300 kW) for operation using biogas (DUAL-FUEL system)

a) Covers for anaerobic ponds (floating plastic membrane) so that the biogas can be contained and utilized.
b) Design, assembly and commissioning of new treatment systems, as well as of systems for an optimum use of the biogas, the sludge, the treated effluent and the empty bunches.
c) Rehabilitation or optimization of existing systems, in particular, to increase the removal efficiency, reduce or eliminate odour and utilize the three process by-products: biogas, sludge and treated effluent


SYSTEMS IMPLEMENTED BY BIOTEC

BIOTEC developed the treatment of effluent (or "sludge") from palm oil mills in biodigesters or in covered ponds (see Process flow chart ).

a) PONDS: This is the best known system and usually the cheapest method of treating palm oil mills effluents. BIOTEC designs the system to ensure that: - The system complies with discharge regulations and is very stable and easy to operate
- Removing the sludge in the ponds is easy and carried out periodically, - There is a simple dehydration and/or utilization system for this sludge, - The treated effluent is used or can be used for ferti-irrigation,
- The anaerobic pond is entirely covered with a floating plastic membrane (liner) that catches the biogas generated for utilization.

b) BIODIGESTERS: These are non mechanically mixed contact biodigesters (followed by clarifiers) with a retention time of 8 to 10 days. We recommend combining biodigesters and ponds to ensure sufficient capacity for absorption of peak flows (peaks of harvesting as well as extra milling). Biodigesters are closed tanks, totally covered with a PVC liner that stores the biogas. They remove 90% of the organic load for very low operating costs and work in a similar way to the ponds, but with lower area and in closed tanks. The liner (membrane) that covers the top collects the biogas for mill use (electricity generation), in addition to preventing it from being released into the atmosphere (methane contaminates the air and is a significant contributing factor to global warming).
Palm oil mills are ideal for the utilization of by-products from the treatment plant:
  • Dry sludge is used as organic fertilizer for the same plantation.
  • Treated effluent is used as liquid organic fertilizer applied to the palm by means of a micro-aspersion system. The cost of this ferti-irrigation system is of the order of US$ 900 per hectare.
  • Biogas is used to fuel the electricity generating plant (fuel engines) that supplies the electricity required by the factory (gas or converted "dual-fuel" engine). The conversion of the fuel engines to a "dual-fuel" system means that biogas can be used as the main but not the only fuel at low cost. Biogas generators are now widespread in the world.
REF: PALMAR SANTA ELENA, Tumaco, Colombia, 120 T of fruit per day
        PALMEIRAS, Tumaco, Colombia, 200 T/day