GB672913A - Method for making organic fertilizer - Google Patents

Abstract

672,913. Fertilizers. EWESON. E. W. April 26, 1949, No. 11081/49. Class 111 [Also in Group XIII] A method of making organic fertilizer by the decomposition of moist organic material through the propagation of aerobic bacteria therein comprises continuously forcing air under pressure through an enclosed mass of such material, all the air being introduced into the mass from the bottom thereof, and continuously withdrawing spent air which has passed through the mass and gases generated within the mass at vertically-spaced intervals throughout the mass. Waste materials such as garbage, sludge, and manure, waste and refuse from canning, fishery and sugar mills, and from distilleries and breweries, wood wastes, weeds, straw, tobacco stems, peat and the like are fed into an open-topped tank 1, Fig. 1, the resulting fertilizer being withdrawn from a conical bottom section 2 through a valve 3. Hot compressed air is supplied to a manifold 4 and thence to distributing pipes 6, Fig. 2, supported by crossbars 11, while used air and generated gases are withdrawn from similar arrangements of collecting pipes 6<SP>1</SP> and manifolds 4<SP>1</SP> communicating with outlet valves 15, spaced vertically in the tank. Arms 19 mounted on a rotating shaft 16 supported by upper and lower crossbars 17, 18, serve to agitate the mixture. An extension 27 carrying a bar 28 stirs the lowermost layer to facilitate discharge. The apparatus may be employed for batch operation, but is preferably used continuously. The tank is initially filled, air passed in, and only the lowermost escape valve 15 opened wide. As decomposition proceeds the continued introduction of fresh air begins to dry the lowest layer of material being treated, and as drying proceeds, decomposition is progressively inhibited. The next layer is then treated by either closing the lowermost valve 15 and opening the next higher one, or leaving the lowermost valve 15 open, opening the next higher one and increasing the total airflow by opening an inlet valve 14 wider. In either case. treatment is continued upwards progressively until all the layers are in a state of progressive decomposition from top to bottom. The material first discharged at valve 3 from below the distributors 6 is either discarded or fed in again at the top of the tank. With equilibrium conditions attained, raw material may be fed continuously or intermittently at the top of the tank and finished fertilizer withdrawn continuously or intermittently at the bottom. Pipes 29 for observation and withdrawal of samples may be provided. The preferred maximum air consumption is ¢ cubic foot per minute per cubic foot of material.