GB1576423A

GB1576423A - Fertilizers and a method of producing and sterilising same

Info

Publication number: GB1576423A
Application number: GB8603/76A
Authority: GB
Original assignee: FARMURA Ltd
Current assignee: FARMURA Ltd
Priority date: 1977-05-23
Filing date: 1977-05-23
Publication date: 1980-10-08

Description

(54) FERTILIZERS AND A METHOD OF PRODUCING AND STERILIZING SAME (71) We, FARMURA LIMITED, a British Company whose Registered Office address is 10 Mill Street, Maidstone, Kent, Great Britain, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to fertilizers, and to a method of and apparatus for producing and sterilizing same.

According to the present invention there is provided a method of producing said sterilizing fertilizer comprising separating solid and liquid excretion of farm animals from a slurry thereof by means of a filter, collecting the extracted liquid and solid, compressing the solid to extract residual liquid, and adding an organic germicide to the slurry, or to the separated liquid and to the solid prior to compression thereof.

Further, according to the present invention there is provided apparatus for carrying out the method aforesaid comprising a rotary vacuum filter for separating liquid and solid excretion from a slurry thereof, a tank for collecting the separated liquid, a screw press for compressing the separated solid to extract residual liquid therefrom, means for feeding said extracted residual liquid to said tank, and means connected to a source of organic germicide for feeding said germicide to the slurry, or to the separated liquid and to the solid prior to compression thereof.

Still further, according to the present invention there is provided fertilizer when produced and sterilized by the method aforesaid.

The germicide may be an aqueous solution of formaldehyde, such as commercial formalin, or a derivative of formaldehyde, or may be chloroxylenol or a quaternary ammonium compound, or may be a mixture of two or more of said substances. A small amount of detergent may be added to the germicide as a wetting agent.

The compressing of the solid excreta may be effected by one or more screw presses.

Preferably, the filter is a rotary vacuum filter.

An example of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of apparatus for use in carrying out the invention according to the present invention, and Figure 2 is a flow diagram.

A portion of the floor of a byre, not shown, is perforate so that solid and liquid cattle excretion may pass directly or be swept through the perforate floor portion to a channel below same which conducts the solid and liquid mixture to a storage tank 1. The mixture, called a sludge or slurry, is fed by a flow inducer 2 from the storage tank 1 to a tank or pit 3, and is pumped hy a screw pump 4 from the tank 3 into the sump 5A of a rotary vacuum filter 5 which extracts the liquid from the solid.

The rotary vacuum filter 5. consists in general of the sump 5A for the mixture, and a rotary drum 5B partially immersed in the mixture in the sump 5A. The drum is hollow so as to provide a vacuum chamber, and the peripheral wall of the chamber is perforate. A vacuum is created in the chamber while the drum turns so that liquid is sucked into the chamber through the perforate wall, leaving solid matter on said wall. The separated liquid passes from the drum 5B to a tank 6, through a pipe 7, and the solid matter is removed from the wall by a scraper, not shown. To the rear of the scraper in the direction of rotation of the drum, there is a roller 5C which presses against solid on the perforate wall so as to squeeze through the wall, liquid remaining in solid.

The vacuum in the drum 5B is created by a water ring vacuum pump 8 which is connected to the top of the tank 6 by a pipe 9, and the vacuum created in the tank 6 causes the flow of liquid from the drum 5B to the tank 6. The tank 6 is connected at its lower end to an extraction pump 10 which pumps the liquid via a flow inducer or flow meter 11, Figure 2, if desired, to a bulk holding tank 12.

The solid removed from the wall of the drum 5B by the scraper falls or is guided on to an endless conveyor 13 which feeds the solid into one or more screw presses 14, Figure 2, in which the solid is compressed and is then passed to one or more bagging units 15.

Sterilization is effected by adding an organic germicide to the slurry, for example in the tank 1. The germicide may be an aqueous solution of formaldehyde, such as commercial formalin, or a derivative of formaldehyde, or may be chloroxylenol or a quaternary ammonium compound, or may be a mixture of two or more of said substances. A small amount of detergent may be added to the germicide as a wetting agent.

Alternatively, the germicide may be introduced into the slurry in the pit or tank 3, or into the sump 5A of the filter, or into the separated liquid in the tank 6 and to the separated solid prior to the latter entering the screw press or presses 14. The germicide is supplied by metering pumps, not shown, at predetermined intervals, and when supplied to the slurry or to the separated liquid, the slurry and liquid are agitated intermittently for a predetermined length of time so that all the slurry and liquid are treated by the germicide, and so that any gas which may be present is removed. When the germicide is added to the separated solid, it is spread throughout the solid by the compressive action of the screw press or presses. The ratio of germicide to the slurry, liquid or solid may be in the region of from about 2% to 5% by volume.

The screw press or presses reduce the moisture content in the solid to an acceptable level of about 57%, and the liquid squeezed out of the solid is fed to a tank 16, Figure 2, and is pumped therefrom by a pump 17 to the holding tank 12. As the solid leaves the screw press or presses, it may be mixed with peat, sand or soil prior to bagging.

As shown in Figure 1, the screw pump 4 and the flow inducer 2 are driven by a motor 18 through a gearbox 19, and the outlet spout or nozzle 20 through which the slurry is pumped to the pump 5A of the filter is provided at its inlet end with a manually operable valve 20A which can be closed, when desired, to effect recirculation of the slurry through the pit or tank 3 until the slurry is of the required consistency, or if the process has to be stopped.

Also in Figure 1, 21 indicates a pipe connecting the upper end of the tank 6 with the liquid extraction pump 10 and having a manually operable valve 21A so that any pressure dif ferential between the ends of the pipe 6A leading from the tank 6 to the pump 10 is substantially eliminated; and 22 indicates the air discharge pipe of the vacuum pump 8 having a silencer 22A and a water seal 22B.

Normally, the filter drum SB and the conveyor 13 are provided with their own driving motors.

As a result of the invention, all or substantially all dangerous bacteria and pathogens in the liquid and solid fertilizer are killed.

In Figure 1, the numeral 23 indicates end walls of a factory.

WHAT WE CLAIM IS: 1. A method of producing and sterilizing fertilizer comprising separating solid and liquid excretion of farm animals from a slurry thereof by means of a filter, collecting the extracted liquid and solid, compressing the solid to extract residual liquid, and adding an organic germicide to the slurry, or to the separated liquid and to the solid prior to compression thereof.

2. The method claimed in Claim 1 in which the organic germicide is an aqueous solution of formaldehyde, or a derivative of formaldehyde.

3. The method claimed in Claim 1, in which said organic germicide is chloroxylenol.

4. The method claimed in Claim 1, in which said organic germicide is a quaternary ammonium compound.

5. The method claimed in Claim 1, in which said organic germicide is a mixture of two or more of an aqueous solution of formaldehyde, or a derivative of formaldehyde, chloroxylenol, and a quaternary ammonium compound.

6. The method claimed in any one of Claims 1 to S, in which the ratio of germicide to the slurry, liquid, or solid is 2% to 5% by volume.

7. The method claimed in any one of Claims 1 to 6, in which detergent is added to the organic germicide.

8. Apparatus for carrying out the method claimed in Claim 1 comprising a rotary vacuum filter for separating liquid and solid excretion from a slurry thereof, a tank for collecting the separated liquid, a screw press for compressing the separated solid to extract residual liquid therefrom, means for feeding said extracted residual liquid to said tank, and means connected to a source of organic germicide for feeding said germicide to the slurry, or to the separated liquid and to the solid prior to compression thereof.

9. The method of producing and sterilizing fertilizer substantially as hereinbefore described.

10. Apparatus for carrying out the method claimed in Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.

11. Fertilizer when produced and sterilized by the method claimed in any one of Claims 1 to 7 or 9.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tank 6 is connected at its lower end to an extraction pump 10 which pumps the liquid via a flow inducer or flow meter 11, Figure 2, if desired, to a bulk holding tank 12. The solid removed from the wall of the drum 5B by the scraper falls or is guided on to an endless conveyor 13 which feeds the solid into one or more screw presses 14, Figure 2, in which the solid is compressed and is then passed to one or more bagging units 15. Sterilization is effected by adding an organic germicide to the slurry, for example in the tank 1. The germicide may be an aqueous solution of formaldehyde, such as commercial formalin, or a derivative of formaldehyde, or may be chloroxylenol or a quaternary ammonium compound, or may be a mixture of two or more of said substances. A small amount of detergent may be added to the germicide as a wetting agent. Alternatively, the germicide may be introduced into the slurry in the pit or tank 3, or into the sump 5A of the filter, or into the separated liquid in the tank 6 and to the separated solid prior to the latter entering the screw press or presses 14. The germicide is supplied by metering pumps, not shown, at predetermined intervals, and when supplied to the slurry or to the separated liquid, the slurry and liquid are agitated intermittently for a predetermined length of time so that all the slurry and liquid are treated by the germicide, and so that any gas which may be present is removed. When the germicide is added to the separated solid, it is spread throughout the solid by the compressive action of the screw press or presses. The ratio of germicide to the slurry, liquid or solid may be in the region of from about 2% to 5% by volume. The screw press or presses reduce the moisture content in the solid to an acceptable level of about 57%, and the liquid squeezed out of the solid is fed to a tank 16, Figure 2, and is pumped therefrom by a pump 17 to the holding tank 12. As the solid leaves the screw press or presses, it may be mixed with peat, sand or soil prior to bagging. As shown in Figure 1, the screw pump 4 and the flow inducer 2 are driven by a motor 18 through a gearbox 19, and the outlet spout or nozzle 20 through which the slurry is pumped to the pump 5A of the filter is provided at its inlet end with a manually operable valve 20A which can be closed, when desired, to effect recirculation of the slurry through the pit or tank 3 until the slurry is of the required consistency, or if the process has to be stopped. Also in Figure 1, 21 indicates a pipe connecting the upper end of the tank 6 with the liquid extraction pump 10 and having a manually operable valve 21A so that any pressure dif ferential between the ends of the pipe 6A leading from the tank 6 to the pump 10 is substantially eliminated; and 22 indicates the air discharge pipe of the vacuum pump 8 having a silencer 22A and a water seal 22B. Normally, the filter drum SB and the conveyor 13 are provided with their own driving motors. As a result of the invention, all or substantially all dangerous bacteria and pathogens in the liquid and solid fertilizer are killed. In Figure 1, the numeral 23 indicates end walls of a factory. WHAT WE CLAIM IS:

1. A method of producing and sterilizing fertilizer comprising separating solid and liquid excretion of farm animals from a slurry thereof by means of a filter, collecting the extracted liquid and solid, compressing the solid to extract residual liquid, and adding an organic germicide to the slurry, or to the separated liquid and to the solid prior to compression thereof.