AU7008398A - Waste treatment - Google Patents

Description

-1I-

AUSTRALIA

ISACT 1990 COMPLETE

SPECIFICATION

FOR A STANDARD

PATENT

ORIGINAL

C. V Name Of Applicant/s: Actual Inventor/s: Address Of Service'.

Royl Jay HarlOW, Nancy Jean H-arlow Roy Jay HARLOW and Nancy Jean

HARLOW

BALDWIN SIHELSTON

WATERS

60 MARGARET

STREET

SYDNjEY NSW 2000 "WASTE TREA:TMENT" I.vefItiofl Title: The following statement is a full description of this inviention: including the best method of performing it known to us:- (File: 20977.00) ~IUMi~nT~ICV*--(TrCRLZis~l"r; ~U2 WASTE TREATMENT BACKGROUND OF THE INVENTION The present invention relates to waste treatment and more particularly, but not exclusively, to dairy shed waste treatment.

To the present time, various proposals have been put forward for the utilisation of organic waste material, whether agricultural, horticultural or human. Typically, such treatment.will be addressing two objectives: Dealing with the waste; and (ii) Converting it into something useful, In the latter regard, organic waste has typically been converted into a fertilised product andlor biogas, including methane.

Many previous proposals have been capable only of batch processing 20 0of material and have not been suitable for dealing with a regular or continuous flow of material.

Other proposals have also not been able to avoid trapping biogas within the waste material or enabling its expeditious release.

The present invention will be described particularly with regard to the processing of dairy shed waste (cow manure), but it will be appreciated by those skilled in the relevant arts that the present invention has application throughout the area of biological waste treatment.

OBJECTS OF THE INVENTION It is, thus, an object of the present invention according to its preferred embodiments to provide an apparatus and/or system and/or process which is able to process dairy shed waste to render it substantially non-toxic and environmentally safe and being able to produce liquid fertliser, soil conditioner and biogas on a substantially continuous basis.

i Further objects of this invention will become apparent from the following description.

SUMMARY OF THE INVENTION According to one aspect of the present invention, there is provided an apparatus for the continuous processing of dairy shed waste or the like to render its substantially non-toxic and produce a liquid fertiliser and soil conditioner, said apparatus comprising a substantially air-tight substantially horizontal housing adapted to receive and hold a predetermined quantity of waste for a predetermined period of time and at a predetermined temperature and pressure sufficient for sustained natural bacterial growth and to allow anaerobic digestion, including the production of gaseous Sproduct.

Preferably, the apparatus as immediately above defined has a housing comprising a substantially horizontal air-tight tank of a size adapted to hold a predetermined number of separate loads of said waste.

20 Preferably, the apparatus as defined immediately above has said tank adapted to receive one load per day of approximately forty loads of said waste.

Preferably, the apparatus as defined immediately above has said tank 5 having a diameter to length the ratio of between 5.5:1 and 4.25:1.

Preferably, the apparatus as defined immediately above has the tank length to diameter ratio of approximately 5:1.

According to a further aspect of the present invention, a system for continuously processing dairy shed waste or the like, to render it non-toxic and to produce a lIquld fertiliser and.soil conditioner and gaseous product includes the provision of a substantially air-tight substantially horizontal environment adapted to receive predetermined quantities of said waste at predetermined time intervals daily to be retained in said environment at a predetermined temperature and time interval, preferably forty daye, to I_ 13 undergo biological transformation and anaerobic digestion resulting in the detoxification of the waste and the continuous release of gaseous product.

According to a further aspect of the present invention, a gas regulator system is adapted to control and harvest a combustible gas generated by a dairy shed waste treatment apparatus or system, said gas control system including flow control means and pressure transfer control means, said system enabling mixing of the waste material by bio-airation and wherein the pressure and fluid control of said system can be substantially maintained during its operation.

Preferably, the gas regulator control system as immediately defined above includes means to combust the combustible gas in facilitating the maintenance of temperature requirements for both biological transformation and anaerobic digestion and the production and harvesting of further combustible gas to substantially make the fertiliser and gas production system substantially self supporting.

Preferably, the gas regulator system as defined above includes 20 process logic control means to monitor system maintenance and control.

Further aspects of this invention which should be considered in all its novel aspects will become apparent from the following description given by way of example of possible embodiments thereof and in which reference is 5 made to the accompanying drawings.

BRIEF IDSRIPTIQO OF THE DRAWINGS FIGURE 1: shows diagrammatically a side perspective view of an 0 apparatus according to one possible embodiment of the invention; FIGUR 2: shows diagrammatically an end view of the apparatus of Figure 1; and a 4 shows diagra mmatiCallY a dairy shed waste processing .system according -to one possible embodiment of the invention.

EDEBQ-MEI

The present invention can be manufactured by any suitable technilque and from any suitable materialsj. although principally concrete, stainless steel 0 nld fibreglassl may be usefully used.

Referring firstly to Figures 1 and 2, an apparatus for processing dairy shed waste to render it non-toxiC and produce a liquid fertilisir and soil conditioner, as well as gaseous product is referenced generally by arrow The apparatus 5 enables this processing9 to be effected continuously from is the dairy shed waste. The apparatus 5 is preferably included within a total system which is shown very diagrammticlly in Figure 3 and which will be described in greater detail later. That total system of Figure 3 allows the continuous processing of the dairy shed waste and the production of the required by-products.

As shown in Figures I and 2, the apparatus 5 -compri5s a substantially horizontal process tank 6 which defines an airtight environment 7 within it. The dome end tank 6 hag an Inlet 8 whereby the shed waste is able to be fed into the environment 7 within the tank 8. The tank 8 further has an outlet 9 whereby after bacterial transformation and anaerobic digestion, the liquid fertiliser may be extracted from the enilronmenlt 7.

Preferably, the outlet 9 may be horizontally and vertically spaced from the inlet 8 so as not to be aligned with it.

Once the shed waste has been fed into the environment 7, it must be retained there for a required length of time suiff icient to enable the biological trmnsformaltion and anaerobic digestion of the waste to be carried out which will process the waste -into the required by-products. The environmen~t 7 Must, therefore, have the necessary controlled conditions of temperature, atmosphere and pressure as well as the appropriate mixing and flow management and moisture content.

As is well known to those skilled in the relevant arts, if animal waste is retained in an air-tight environment for a period of twelve to sixty days at a temperature of from 5 0 C to 40 0 C and a moisture content of 60% to then gas production can be achieved from the waste.

The present invention is believed to be able to achieve optimum biological transformation providing non-toxic fertiliser production from dairy shed waste by functioning on a retention time period of approximately forty Sdays and at a pressure of approximately 70kpa maximum, at a moisture co 10 ennt of preferably approximately 85%. at an optimum temperature of approximately 37 0 C and coupled with a prescribed dimension to volume ratio integrated into the design of the tank (this is the length to diameter ratio previously mentioned). The tank 6 preferably also has one or more baffles 22 strategically placed along its length and an injector mixing system 11 to provide more optimum performance.

The apparatus 5 has been designed to maintain an optimum environment within the tank 6 while being supplied with waste material on a regular daily basis.

The volume of the environment 7 within the tank 6 may preferably be determined by the expression: V daily load x 40 (max.-min. to 5%1, "i 25 For any given application, the daily load and unload may be assumed to be substantially constant and the additional 7% can allow for space above the waste within the environment 7,.6 for the gaseous products to collect.

After the initial setting up period, each day as a quantum of waste is mixed with water to attain the desired moisture cornact and is then fed in through the inlet.8, as shown in Figure 1, each quantum within the environment 7. is thereby displaced by an increment along the tank 6 and the quantum which has been in the tank 6 forthe longest time is preferably taken simultaneously from the outlet 21 at the opposite end of the tank 6.

With the controlled environmental conditions within the environment 7 including the use of the injector mixing system 11 and with the inlet 8 and the outlet 9 preferably being at opposite ends of the tank 6, the waste S nearest the outlet 9 will be of a biologicaHy transferred state which has passed its optimum gas generating condition and is now in a non-toxic condition and may be withdrawn from the tank 6 as fertiliser and/or soil conditioner.

As each quantum of waste within.the environment 7 has been in the tank for a distinct and different length of time, a quality gradient is created in the waste, namely at the end nearest the inlet 8 the waste has commenced biological transformation but has not commenced anaerobic digestion and is thus giving off no gas whereas nearer the centre of the environment 7, anaerobic digestion is strong and gas production is highest and at the end nearest outlet 9, anaerobic digestion has passed its peak and thus is not giving off any significant amount of gas and will without agitation naturally collect on the outlet side of baffle 22 in the form of fertiliser and soil conditioner.

The tank 6 is dimensionally adjusted, in particular, its length to diameter ia preferably within the range 4.25:1 and 5.5:1 and preferably of the order of 5:1 and this has been found in tests to ensure that the gradient Is maintained along the length of the tank 6'for the continuity of the process to be maintained.

Additionally, the injector system 11 provides that gas may be recycled into the digesting material-from the regulator 14 (see Figure 3) to aid volcanic action and stimulate bacteria growth in selected segments of the tank 6 prior to the baffle 22.

Additionally, the pH rating of the bacteria may be monitored through port 12. The provision of the port 12 can be of considerable significance during "start up" procedures when additional overseeing will be required to ensure that the process stabilises and continues in the proper manner.

I

I

Referring now more particularly to Figure 2, a sub-tiank 20 is shown cradling the tank 6. This sub-tark 20 preferably holds water which may be heated by a gas burner inserted in tube 10 and passed through the sub-tank in a closed circuit. This will provide the necessary temperature control for optimum bacteria growth. Temperature control as well as other environmental and functional controls can be maintained by the PLC system 4.

Also, shown in Figure 2 are the fertiliser and soil conditioner outlets S. A level indicator or sight glass 13 is also shown. There are also ports 1 provided for inspection and cleaning of the tank 6 during shut-down, Gas emanating from the digesting waste will collect above its surface is and can pass out through a collector 17 provided on the upper portion of the tank 8. A pressure release valve 18 is also shown provided in association with the collector 17, Insulation, (not shown), mnay be provided around the outer surface of the tank 0 and As shown in Figure 3, the apparatus of Figures 1 and 2 may preferably be incorporated in a larger integrated system which can ensure the continuous production of fertiliser and soil conditioner and gaseous products and allow the gas produced to be recycled for heating and mixing in a continuous process to ensure the production of further gas and fertilizer.

Referring to Figure 3, the gas from collector 17 is shown being directed to gas regulator 14 through valve 30. Part of the gas from the gas regulator 14 can be cycled back into-the environmnent 7 in the procane tank through a closed circuit injection manifold I1I to provide any necessary aid agitation of the waste in the tank S. This agitation can ensure the continuous production of further gas and aid the complete transforma-tion and/or production of fertillsar and soil conditioner in the process tank 6. The bulk of the gas produced, however, is passed to the gas storage unit 25 and a portion of the gas ran be lead to a gas fired burner 23 to provide the heat requiremnens for the system, surplus gas being diverted for alternative energy requirements indicated at 26.

U

Water hated in the sub-tank 20 can provide controlled temperature conditions within environment 7 in the tank 8 or may be diverted as a byproduct for altemative water requirements as indicated at 27. A shad waste collector 29 is suitably- provided or may be constructed as a standard shad fixture. The waste. collector 29 *will preferably provide for an Initial mixing of the waste with water to provide an initial water content.

On the outlet 9 side of the tank 8, by-product tanks 28 can be provided to receive the products which will subsequently be used for fertilisar and sail conditioner.

It Is envisaged that the by-product storage vessels 28 can be portable and not necessarily be Integral fixed parts of the entire system.

It will thus be appreciated that the present invention provides a simple yet effective substantially horizontal system and apparatus and process for continually processing dairy shed waste to produce non-toxic liquid fertilise and soil conditioner and gas for energy and, in an integrated can further provide the recycling of the biogas as a non-combusted air medium and use the energy derived therefrom to facilitate the further production of the fertlilser and gas from the naturally available dairy waine.

The term 'dairy shed waste" Is used throughout this specification for simplicity but It will be appreciated that-the term covers any equivalent type of biological animal warn?.

Where in the foregoing description, reference has been made to specific components or integers of the invention having known equlvalenyta then such equivalents are herein Incorporated as if indivdually so% forth.

Although this invention has been described by way of example and with reference to. possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from fna scope of the Invention, to defined In the appended claims.

Claims (8)

1. Apparatus for the continuous processing of dairy shed waste or the like to render its substantially non-toxic and produce a liquid fertiliser and soil conditioner, said apparatus comprising a substantially air-tight substantially horizontal housing adapted to receive and hold a predetermined quantity of waste for a predetermined period of time and at a predetermined temperature and pressure sufficient for sustained natural bacterial growth and to allow anaerobic digestion, including the production of gaseous product.

2. A system for the continuous processing of dairy shed waste or the S" like, to render it non-toxic and to produce a liquid fertiliser and soil 15 conditioner and gaseous product includes a substantially air-tight environment to receive prescribed quantities of waste at predatermined time intervals to be retained in said environment at a predetermined temperature and time interval to undergo biological transformation and anaerobic digestion resulting in the detoxification of the waste and the continuous release of gaseous product, without violating the controlled atmosphere provided by said apparatus.

3. An apparatus as claimed in Claim 1. wherein said housing comprises Sa tank of a size sufficient to hold a predetermined number of loads of said waste.

4. An apparatus as claimed in Claim 3, wherein said tank is adapted to receive approximately forty substantially equal daily loads of said waste. An apparatus as claimed in Claim 4. wherein each said load is retained for a period of approximately forty days.

6. An apparatus as claimed in any one of Claims 3 to 5, wherein the ratio of the length to diameter of said tank is in the region of 5.F; 1 4.25:1.

7. An apparatus as claimed in Claim 8, wherein said ratio Is approximately 5: 1. a. An apparst us as claimed In Cl'aim I or any one of Claims 3 to 7, wherein said housing has-at least one inlet to receive said waste and at least one outlet to discharge said feortilisar and wherin. said inlet(s) and sold outlet(s) are not aligned with one another. An apparatus substantially as herein described with reference to Figures 1 and 2 and/or Figures 1, 2 and 3 of the accompanying drawings, *10. A system for continuously producing fertiliser, soII conditioner and gaseous products from dairy shed waste Incorporating srn apparatus as claimed in any one of Claim 1 or Claim. 2 to 9.

11. A system as claimed in Claim 2 or Claim 10. wherein a proportion of the gaseous product Is fed back Into the waste undergoing transformation to agitate it and harvest gas from said waste 2t an appropriate place along said tank and at an appropriate stage of biological transformation. I'12. A system as claimed in Claim 1 1, wherein a proportion of said gaseous materili In combusted In providing heating for the waste undergoing transformation.

13. A system as claimed in any one of Claims 2 or 10 to 12 In which the pressure in said environment is no more than 14, A system as claimed In Claim 13, wherein the temperature In said environment is approximately 370'C. A systemn substantially as herein described withi reference to the accompanying drawings. U 11 1 6. A irocess for the continuous processing of dairy 3hed waste substantially as herein described With reference to the accompanying drawings. DATED this 11th Day of June, 1998 ROY JAY HARLOW and NANCY JEAN HAiRLOW Attorney: PAUL G HARRISON Fellow Institute of Patent Attorneys of Australii of BALDWIN SHELSTON WATERS