Industrial Wugtes
CITRUS CANNING INDUSTRY ROBERT R. MCNARY Citrus Products Station, U. 5. Department of Agriculture, Winter Haven, Fla.
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HE growmg marketmg and procFing of citrus fruits is one a great boon to the . ' , ' . . ' ) . of Flonda s malor mdustries. Next to tourists, citrus fruits eated another. The bring in the Geatest profit to the state. In the early days canning residue contains about 82% water. This must be reoranges, grapefruit, and tangerines were m&keted only as fresh duced to 8% in the Iinished feed. The removal of:this water in fruit. The waste requiring disposition was the spoiled fruit and the h g e tube dryers used for the solid peel is comparatively excuJls that were below shipping grade and had to he disposed of pensive where fuel costs are relatively high. Furthermore, in locally. T h w were either dumped on waste land or returned to Florida, where the humidity is fairly high, drying the feed withthe.groves, where they were plowed under to add humus to the out preliminary pressing produces a hygroscopic feed which may soil. However, the amount of culla that can be advqtageously ahsorb atmaspheric moisture and finally become moldy. Couworked into the soil is limited. Consequently, when the canning sequently as much water as possible is sqneeaed out before dryof fruit began to reach large volume, the amount of waste peel, ing. The addition of lime to the ground solids makes it possible pulp, and seeds became so great that former methods of disposal to redue the water content fmm 82 to72% or less by preasing. were entirely inadequate. The dumping of this material created In so doing, about €Xi% of the weight of the originai residue is a public nuisance by reason of the had odors that developed and obtained as presa liquor or peel juice. This liquor contdm 8 to the swarm of insects that bred ou the refuse. 12% total dissolved solids, of which 5 to 7% is sugar. It was The development of dehydration plants to process citrus waste formerly:bnsjdered as~awasta, and as such it is the most difficult into cattle feed killed two birds with one stone. I&.suppliedan citrus waste to disme of withput causing complaint OF nuieanoe. outlet for vast quantities of solid citrus refuse and at the same It has an oxy@ consumed value (from permangmate) in the time gave cattle raisers and dairymen a much-needed addition to neighborhood of 40,003~padg per million (p.p.m.). It is quite esttle rations. The f a d that it is almost purely a carbohydrate unstable and quickly pollutes any body of water into which it is feed and must he supplemented with other mikerial to complete put. A number of disphssi methods have been tried, and every the ration is beside the point as far as we are concerned here: one has given trouble, with oue exmption. There is some douhc that the canning of orapge and grapefruit This exception is the method used hy a few milk that are lojuices would have had such atremendous growth in recent years cated in fairly large cities and can add their pliquor to city if no ready means had been available for disposing of the residues. sewage. This merely transfers the burden of treatment of the It is estimated for the 1945-46 seasan that 1,805,003 tons of waste liquor from the cannery to the city, When' the canniog Florida fruit were processed in the canning plants. Since the plant and the feed mill are comparstively small and the cityxis peel, seeds,and rag amount to about 57% of the whole fruit, about comparatively Large, the two wastes can be treated together quite 1,030,003 tons of residue containing 82% moisture were produced. well. The citrus waste is high in carbohydrates hut low in nitroFrom this were m a n u f a d d more than 80,003 tons of cattle gen, and the city sanitary sewage.is high in nitrogen. The mixfeed; this indicates that approxhately 60% of the residue was ture of the two supplies dl the necessary nutrients for a rapid used for this purpose. microbial action and There are four reasons consequent reduction for the unoroceased mrof the biochemical oxytion: First, certaid of geu demand (B.O.D.), b b Former methods of disposal of waste materiale of the smaller canneries provided the proportion the citrus canning plants in Florida beeame entirely are too small to operate of citm waste is not inadequate when the number and size of these plantheir own feed mills so large as to upset increased. Approrimately 80% of the peel, seeds, and rag and are located too far microbial equilibrium. from juieing and seotionieing operations are now dried to from an established feed Just what the limitmake cattle feed. Before drying, as much as possible of mill to permit ecoing proportion is has the water is pressed out; thie press liquor was formcrly nomical transportation. not been determined. wasted. Most of it is now eoncenuatedto eitrus molasses, Second, some freab peel Another disadvantage to which is added to animal feeds, and mme is fermented is always fed to nearthe city sewage treatto beverage alcohol. The growing of feed yeast on press by cattle herds. Third, ment plant is that citrus liquor is being investigated and holds considerable promat the beginning and canning operations m ise. Other liquid wastes from juicing and seetionidng end of t h e season seasonal and the peak operations are mora dilute but are e a t e r in volume. the canning operations occurs at the height of A t p-t these wastes are either added to city sanitary are too light t o the tourist s e w n in sewers, pumped to natural sand filters, or added to near-by warrant operating the Florida. Consequently lakes, streams, salt water sea, or bays. Trickling filters f e e d mills. F o u r t h , a sewage plant treathave been found deotive, on an experimental scale, in the deh
