One of the largest citrus processors in California uses an interesting technology to dispose of their orange peel. Like their Florida counterparts, they run the citrus peel through screw presses, getting the peel from 82% down to 70% press cake moisture. However, they have no dryer or WHE (waste heat evaporator) for processing their peel.

Instead they use a steam evaporator for processing the press liquor from the presses. The evaporator removes 60,000 #/hr of moisture at a feedmill that processes the peel from 2250 boxes (use 44 pounds of peel per box) of oranges an hour.

They process the press liquor (plus spent caustic, oil house water and other waste streams) in the steam evaporator. It makes molasses at 50º to 55º Brix. Originally they put some of the molasses on the press cake, and they sold the rest as a liquid cattle feed.

Later they found they could make higher profits by selling the molasses to a distillery. The distillery makes citrus alcohol at 195 proof. This alcohol is used at a winery that produces fortified wine.

The processor’s practice has been to sell the press cake under an annual contract with commodities brokers, either Foster or Coast Grain. These brokers take it in bulk, 30 to 40 loads a day (nominal 40,000 pounds per truck). At peak season this was too much press cake for the farmers to accept: the material would spoil before the cattle would consume it. As a result, at one time the press cake was piled on a concrete airport runway. This was not satisfactory because soon liquid started to drain from the press cake (contaminating the area), and solids (nutrients) were lost. Also, the cake started to ferment: the cows liked it that way, but it released CO2 in the digestive process which was harmful to the cows.

Given this situation, one of the brokers developed the technology to bag the press cake. The bag keeps the oxygen out, and the material will keep for several months. Ensilage (anaerobic acid fermentation) takes place.

The bag is made in the pasture at a dairy or feedlot. The press cake truck coming from the citrus processing plant dumps its load into a hopper or funnel. This field hopper has wheels and a frame that forms the plastic bag. At times the brokers put in other feedstuffs (by-products from local agricultural processing plants) besides the citrus press cake. The bags are about 10′ in diameter. They look like giant sausages, about 8′ tall, 100, 200, and even 300 feet long.

The farmer slits the plastic bag as needed to expose feed to his livestock. Sometimes the feed is removed from the bags with a front end loader.

The possibility of using this technology has been raised for storing forage grasses and other feeds. There have been inquiries regarding alfalfa, sugar cane, and produce waste, but so far we are not aware of any projects that have been funded.

Supplier: Ag-Bag International, Ltd., Warrenton, OR 1-800- 334-7432