Banana Waste

January 12, 2009

Periodically Vincent Corporation receives inquiries in regards to handling waste from banana plantations and processors.  These involve three kinds of waste:  banana peel, banana stems, and banana trunks.  The peel falls in two separate categories:  ripe banana and green banana.  

RIPE BANANA PEEL.  Recently inquiries have increased with the hope that the waste can be converted into valuable animal feed.  Vincent undertook tests seeking a practical process.  We found that banana peel (yellow, with some brown spots) was about 88% moisture.  When pressed, some press liquor was produced, measuring 7 Brix.  However the press cake was still a very humid 84% moisture.   This is too high to be converted into a dried animal feed.

Tests were conducted to determine if the use of a press aid would make the material pressable.  Lime, the old standby, as well as gypsum and alum, along with wood fiber, were added to the shredded peel.  None of these press aids worked.  The press cake still came out over 80% moisture.  If we cannot do better than that, a feedmill will never be justified.

GREEN BANANA PEEL.  One customer in Jamaica processes green bananas.  (Green bananas are very hard to peel; just try a batch.)  The challenge here was to shred the waste in order to reduce the volume being hauled to landfill.  Green banana peel has enzymes which make it very sticky and hard to handle.  This presented a challenge for our shredder; however, the comb style shredder proved a satisfactory solution.

BANANA STEMS.  When banana bunches are harvested, there is a stem about 18” long and 3” in diameter at the end of the bunch.  This stem is cut off in the packing plant.  One customer in Costa Rica used Vincent twin screw presses to dewater these stems.  After shredding, the stems released a great deal of moisture in the press.  However, like ripe peel, the press cake still had a high moisture content.  The concept was to dry this press cake in order to produce a woody fiber.  Unfortunately, the cost of the dryer operation exceeded the value of the dried product, and the operation folded.

The plantation where this operation was located took over the screw press.  Their intent was to eliminate a waste disposal problem and produce a press cake that was suitable for mulching.  Since the mulch did not need to be as dry as what the twin screw press was designed to produce, we recommended a much less expensive Series KP press for future installations.  Good mulch material was produced, but, in the end, the project was abandoned.  The mulch became a breeding ground for insects in the wet climate.

This mulch could be used as a feedstock for a paper mill.  After all, it is cellulose fiber.  It has the advantage of having a year-round supply (in contrast to making paper out of corn stalks or wheat straw).  Nevertheless the scale of operation does not appear to be sufficient to justify the investment in a paper mill.

BANANA TRUNKS.   A development project in Colombia involves shredding and pressing the trunks of banana plants.  The volume and size is much larger than banana stems.  However, the process would be the same.

ETHANOL.  The largest producer of alcohol in Ecuador uses banana waste.  Because of the Brix content, the material readily ferments.  That is cheaper than using corn syrup, but the volume is not there.

Issue 206