GB787983A - Apparatus for digestion of organic material - Google Patents

Abstract

787,983. Composting devices for organic refuse. RUSKIN, F. R. Sept. 29, 1953, No. 26716/53. Class 111. An apparatus for fermentation of organic refuse comprises a chamber and a plurality of screens mounted for independent horizontal movement in superposed relation across the chamber and means for drawing and withdrawing such screens across the chamber and means to introduce refuse into the chamber at a point above the uppermost screen whereby the screens may be successively extended across the chamber beginning with the lowermost and refuse can be piled on each before the higher screens are drawn across the chamber. The screens are preferably in the form of roller blinds which can be drawn horizontally across the chamber and wound up when not in use. The fermenting apparatus, which is preferably mobile for towing behind a vehicle, is shown in Fig. 1. The container 10 mounted on road wheels 12 is provided with screens 16, a, b, c and d made up of a number of slats which extend laterally across the entire width of the chamber. The screens 16 can be withdrawn by rotation of shafts 47 and are pulled across the chamber by cables 49. Each of the screens 16 is preferably provided with associated spreading blades 96 which ensure uniform distribution of the refuse in a layer about 6 inches in depth. The spreading blades 96 move in slots 98. Refuse is fed to the apparatus through a bucket 13 which moves from the position indicated in dotted lines to the upper position shown in full lines, where it is tilted through an opening 14 into a hammer mill 15 which grinds the refuse into particles of “ to 1 inch in diameter. The refuse falling onto the lowermost screen is spread out by the associated spreader blade 96 until a layer of the requisite height is attained, after which the next successive screen 16 is drawn across the chamber and the operation repeated. The dumped refuse is preferably innoculated by spraying it with an enzymatic digestion material and a micro-organism culture through a nozzle 82 which is fed by lines 81 and 84 with the requisite digestion and culture mediums from tanks 79 and 83 (not shown). If desired one of these tanks can be connected to the floor of the chamber by a pipe whereby the juices from the fermenting mass can be collected and resprayed onto the top. A suitable microorganism culture is that of alcaligenes fascalis. After the mass in the chamber has been digested for 48 hours thermal bacterium cultures together with a nutrient medium of autolyzed yeast containing finely ground particles of Calcium phosphate and carbonate may be added to neutralize alkaline amines and gradually to bring the pH to neutral. As a further aid to the digestive process moulds particularly of the myxomycetes group may be added. The temperature of the mass is suitably maintained between 45‹ and 55‹C. by means of the insulation of the chamber and by heating units such as 86 placed at the top and the bottom of the chamber. The aeration of the mass is effected by the opening and closing of door 29 as the buckets of refuse are emptied through aperture 14. On closing the door a small flow of air is engendered in the chamber, each closure of the door 29 forcing a small amount of air out through an aperture 92 in a door 91 placed at the bottom of the chamber 10. In operation the digestion apparatus is towed behind a vehicle and filled with refuse until all the screens are full and then returned to a parking place to allow the digestion to proceed. During the initial part of this period the door 29 may be left open to permit gentle ventilation. After four days the lowermost screen is withdrawn and at 12 hour intervals the successive screens are withdrawn whereby the contents are heaped on the floor 39 of the chamber. At this stage the rate of ventilation may be increased by operating the bucket 13 thereby opening and closing the door 29 causing air to flow into and through the chamber. On the sixth day one part of vermiculite to every 40 parts of organic material is introduced into the chamber through the hammer mill 15 and allowed to remain with the end product. Bentonite or Fuller's earth may similarly be employed thereby reducing the moisture content of the mass to 8 to 10 per cent. On the 7th day the process is complete and the contents are removed by opening door 91 and pivoting the whole of the apparatus about shaft 93 by means of a piston 94.