GB2620914A

GB2620914A - Waste Treatment

Info

Publication number: GB2620914A
Application number: GB2210566.2A
Authority: GB
Inventors: O'reilly Shane
Original assignee: I/o Electrical & Mech Ltd
Current assignee: I/o Electrical & Mech Ltd
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2024-01-31
Also published as: GB202210566D0

Abstract

A waste treatment facility comprising: an effluent pit 102 in which waste from the facility collects; and a spraying system 103, wherein the spraying system is configured to spray acidified water in situ onto waste collected in the effluent pit. The facility may be an animal housing facility and the effluent collected may be animal waste. The effluent pit may comprise a gas sensor configured to generate a sensor signal indicative of one or more types of gas and to communicate a corresponding sensor signal to the control unit so that the spraying system may be activated. The spraying system may comprise an acidified water storing means, a flow control device for controlling the flow of acidified water from the storing means to the spraying system and a control unit for controlling the flow control device. A method of treating waste using the facility, and a spring system for incorporation into the facility are also disclosed.

Description

WASTE TREATMENT

Technical Field

The present invention relates to techniques for treating waste.

Background

To increase crop yields, it is necessary for soil to be fertilized. Animal slurry is a good fertiliser as it is typically widely available in agricultural settings and reduces reliance on chemical fertilisers. During fertilising operations, animal slurry is added to the soil. Previously, animal slurry was simply spread on the soil to be fertilised. Nowadays, however, to reduce its polluting effects, animal slurry is more commonly added to soil by an injection process where it is injected directly into the soil.

Whilst a good fertiliser for the reasons mentioned above, slurry from animals is a source of emissions that are considered harmful to the environment, in particular ammonia. In many jurisdictions, increasingly strict environmental regulations require ammonia reducing acid to be added to slurry before it is used in fertilising operations. This typically requires the machinery used for fertilising operations to be equipped with tanks of acidified water (typically diluted nitric acid) and means to add acidified water from these tanks to the slurry as it is being injected into the soil.

As well as making fertilizing operations generally more complicated and expensive, for normal agricultural workers, such tanks of acidified water can be awkward to work with and can potentially give rise to serious hazards, particularly if the production of the acidified water requires large quantities of concentrated acid solutions to be stored and mixed.

Summary of the Invention

In accordance with a first aspect of the invention, there is provided a facility comprising: an effluent pit in which waste from the facility collects, and a spraying system. The spraying system is configured to spray acidified water in situ onto waste collected in the effluent pit via spraying means to reduce harmful emissions being emitted to the atmosphere from the collected waste.

Optionally, the facility is an animal housing facility for housing animals, and waste from animals housed in the facility collects in the effluent pit. The spraying system is configured to spray acidified water onto waste collected in the effluent pit via spraying means to reduce ammonia emissions from the collected animal waste when the animal waste is subsequently used as crop fertiliser.

Optionally, the spraying system further comprises an acidified water storing means configured to stored acidified water to be sprayed onto the waste collected in the effluent pit via the spraying means.

Optionally, the spraying system further comprises a flow control device for controlling flow of the acidified water from the acidified water storing means to the spraying means.

Optionally, the facility further comprises a control unit for controlling operation of the flow control device.

Optionally, the control unit is configured to control the flow control device so that the acidified water is sprayed onto the waste collected in the effluent pit periodically.

Optionally, the control unit is configured to control the flow control device so that the acidified water is sprayed onto the waste collected in the effluent pit periodically for a predetermined duration.

Optionally, the facility further comprises a gas sensor located in the vicinity of the effluent pit and configured to generate a sensor signal indicative of a concentration of one or more types of gas in the vicinity of the effluent pit and to communicate a corresponding sensor signal to the control unit. The control unit is configured to control the flow control device to so that the acidified water is sprayed onto the waste collected in the effluent pit if the sensor signal indicates that the concentration of one or more gases in the vicinity of the effluent pit has exceeded a predetermined level.

Optionally, the spraying system further comprises means to replenish the acidified water storage means with water from a water supply after acidified water has been sprayed onto waste collected in the effluent pit, and a pH monitoring unit for monitoring the pH of acidified water in the acidified water storing means and an acid pump. The pH monitoring unit is configured to control the acid pump to pump acid from acid storage means into the acidified water storage means if the pH of the acidified water drops below a predetermined pH level.

Optionally, the predetermined pH level is approximately between 3 and 5.5.

Optionally, the acidified water storage means comprise a circulating pump to mix the water from the water supply with the acid from the acid storage means.

Optionally, the acidified water storage means comprises a fluid storage tank.

Optionally, the spraying means comprises one or more nozzles.

Optionally, the spraying means comprises an array of nozzles.

Optionally, the facility is animal housing facility and the array of nozzles are located underneath a grated floor of the animal housing facility through which waste from animals housed in the facility passes.

In accordance with a second aspect of the invention, there is provided a method of treating waste. The method comprises: collecting waste from a facility in an effluent pit forming part of the facility, and spraying the collected the effluent pit, in situ, with acidified water.

Optionally, the step of collecting waste comprises collecting animal waste from animals housed in an animal housing facility in an effluent pit forming part of the animal housing facility, and the method comprises using the sprayed waste to produce fertiliser.

In accordance with a third aspect of the invention, there is provided a spraying system for incorporating in a facility comprising an effluent pit in which waste from the facility collects.

The spraying system comprises spraying means for spraying acidified water onto waste collected in the effluent pit.

In accordance with certain aspects of the invention, a facility including one or more effluent pits is provided with a spraying system which is configured to spray waste collected in the one or more effluent pits with acidified water to reduce emissions. Treating collected waste at the point it is collected On situ) is advantageous because it reduces harmful emissions from the waste as it is collected; and reduces the requirement to subsequently treat the collected waste.

In accordance with certain embodiments of the invention, an otherwise conventional animal enclosure facility including an effluent pit for collecting animal waste from animals housed in the facility is adapted to include a spraying system for spraying acidified water on animal waste that has collected in the effluent pit.

This arrangement means that slurry for fertiliser formed from the animal waste collected in the effluent pit is treated with acidified water in situ at the point at which it is produced/collected.

When the animal waste collected in the effluent pit is then subsequently used in fertilising operations, it is already treated either reducing or eliminating the requirement to add acidified water to the slurry during, or directly before, fertilising operations. Consequently, this reduces or eliminates the requirement of machinery used in fertilising operations to be provided with awkward and potentially hazardous acidified water storage tanks; and, more generally by minimising or eliminating the requirement for acidified water to be added during or directly before fertilizing operations, the cost and complexity of such fertilizing operations can be reduced.

Furthermore, advantageously, by adding acidified water to animal waste as it is collected, the emissions to the atmosphere of harmful gases including ammonia from the effluent pit is reduced. This improves the welfare of animals housed in the animal enclosure and reduces the pollution produced by the facility.

Further still, by adding acidified water to animal waste that is formed by diluted nitric acid, the fertilizing effect of slurry produced from the animal waste is improved because of the prolonged exposure of the animal waste to the nitrogen component of the acidified water.

Advantageously, spraying systems in accordance with embodiments of the invention can be readily retrofitted to existing facilities (such as animal enclosures) or can be easily incorporated in new facilities (such as animal enclosures) as they are being constructed.

Various aspects and features of the invention are defined in the claims.

S

Brief Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings where like parts are provided with corresponding reference numerals and in which: Figure 1 provides a simplified schematic diagram providing an exploded view depicting the positioning of a spraying system within an animal facility in accordance with certain embodiments of the invention, and Figure 2 provides a simplified schematic diagram depicting in more detail components of a spraying system in accordance with certain embodiments of the invention.

Detailed Description

In accordance with certain embodiments of the invention, an otherwise conventional animal housing facility comprising an effluent pit into which waste from animals housed in the facility is collected, is adapted to include a spraying system which sprays the animal waste collected in the effluent pit with acidified water. An example embodiment is described further with reference to Figures 1 and 2.

Figure 1 provides a simplified schematic diagram providing an exploded view depicting the positioning of a spraying system within an animal enclosure in accordance with certain embodiments of the invention. Such a spraying system can be retrofitted to an animal enclosure or incorporated in an animal enclosure as it is being constructed.

Figure 1 shows the grated floor 101 of an animal enclosure which is positioned over an effluent pit 102. Waste from animals housed in the animal enclosure passes through grates of the grated floor 101 and collects in the effluent pit 102.

Suspended beneath the grated floor 101 is a nozzle array 103 configured in use to spray acidified water on effluent collected in the effluent pit 102. The nozzle array 103 is connected to a flow control arrangement 104 which is configured to control the flow of acidified water to the nozzle array 103 from a storage tank arrangement 105. The nozzle array 103, flow control arrangement 104 and storage tank arrangement 105 collectively form a spraying system.

Figure 2 provides a simplified schematic diagram depicting in more detail components of the flow control arrangement 104 and storage tank arrangement 105.

The storage tank arrangement 105 comprises an acidified water storage tank 201 in which acidified water is mixed and stored. The storage tank arrangement 105 further comprises an acid container 202 which is connected to the acidified water storage tank 201 via an acid pump 203. In use, the acid container contains a supply of acid, typically nitric acid.

The acid pump 203 is connected to a pH sensor 204 configured to detect the pH of the acidified water in the acidified water storage tank 201. The acidified water storage tank 201 further comprises a circulating pump 205 for mixing the acidified water stored in the acidified water storage tank 201 and a water inlet 206 from a water supply. The acidified water storage tank 201 further comprises a pressure relief valve 207 which is configured to prevent the pressure in the acidified water storage tank 201 exceeding a predetermined pressure limit.

The acidified water storage tank 201 comprises an outlet 208 which connects the acidified water storage tank 201 to a flow control valve 209 of the flow control arrangement 104 which controls the flow of acidified water stored in the acidified water storage tank 201 to the nozzle array 103. The flow control arrangement 104 further comprises a valve control unit 210 which is connected to the flow control valve 209 and controls its operation.

In typical implementations, the acidified water storage tank 201 will be located relative to (i.e. at a greater height) the nozzle array 103 to produce sufficient pressure so that the acidified water is sprayed from the nozzle array 103 simply by opening the flow control valve 209.

However, in implementations where this is not the case, a flow control pump can be provided instead of, or in addition to, the flow control valve 209 to pump acidified water from the acidified water storage tank 201 to nozzle array 103.

The components of the spraying system are typically made from suitable corrosive resistant materials, for example stainless steel.

In use, the valve control unit 210 is configured to periodically activate the flow control valve 209 causing acidified water from the acidified water storage tank 201 to flow to the nozzles of the nozzle array 103 and acidified water to be sprayed on effluent collected in the effluent pit 102. The frequency with which spraying occurs and the duration of the spraying is controlled by the valve control unit 210.

This frequency and duration of each spraying operation can be set at any appropriate values. For example, the valve control unit 210 may be configured to control the flow control valve 209 to perform four spraying operations a day, each of a duration of 30 minutes.

As the skilled person will understand, the total volume of acidified water sprayed on an effluent pit in accordance with embodiments of the invention will depend upon the volume of waste stored in the effluent pit and the type of waste. In a typical example, there may be a ratio of 1000:1 between the volume of waste and volume of acid added to water and then sprayed on the collected waste. Thus, for example, for every 1000 litres of collected waste, 1 litre of acid is mixed with water and sprayed on the waste as acidified water during a given spraying operation.

The valve control unit 210 can be provided by any suitable control device as are well known in the art, for example a PLC (programable logic controller), an "embedded" system including a programmable microprocessor or a suitable personal computer.

The valve control unit 210 typical includes input means (for example, a display with a keypad, keyboard and/or mouse; or a touchscreen) for enabling an operative to control the operating parameters of the valve control unit, for example the frequency and duration of the spraying operations.

The flow control arrangement 104 further receives input from a slurry pH sensor 211 and a gas sensor 212.

The slurry pH sensor 211 is typically located in the effluent pit 102 and is configured to detect the pH of the waste collected in the effluent pit 102 and send a corresponding sensor signal to the valve control unit 210. The gas sensor 212 is typically located in the vicinity of the effluent pit 102 (a typical location is shown in Figure 1) and is configured to detect levels of harmful gasses including ammonia gas and send a corresponding sensor signal to the valve control unit 210 As well as controlling the flow control valve 209 so that the nozzle array 103 periodically sprays waste stored in the effluent pit 102 as described above, the valve control unit 210 is also configured to control the flow control valve 209 so that acidified water is sprayed from the nozzle array 103 onto waste collected in the effluent pit 102 if the gas sensor 212 generates a sensor signal indicating that the ammonia gas concentration (and/or any other harmful gas that the gas sensor is configured to detect) has exceeded a predetermined level. The valve control unit 210 controls the flow control valve 209 to continuing spraying acidified water until the sensor signal from the gas sensor 212 indicates that the ammonia gas concentration has fallen below the predetermined level.

The valve control unit 210 is configured to suspend spraying operations if the signal from the pH sensor 211 indicates that the pH of the waste collected in the effluent pit 102 has reached a desired pH level.

As a spraying operation is conducted, the quantity of acidified water in the acidified water storage tank 201 will reduce. After a spraying operation has been completed, the acidified water storage tank 201 is replenished with water from the water inlet 206. This is typically done automatically by a suitable valve/pump arrangement (not shown) which can detect the level of fluid in the acidified water storage tank 201.

The pH of the acidified water is detected by the pH sensor 204 which sends a corresponding sensor signal to the acid pump 203. The acid pump 203 is configured to pump acid from the acid container 202 if the sensor signal from the pH sensor 204 indicates a pH level which is below the desired pH level. In typical embodiments, the pH level will be between 3 to 5.5. The circulating pump 205 is configured to continuously or periodically circulate the acidified water in the acidified water storage tank 201 to ensure that acid from the acid container 202 is mixed with water from the water inlet 206. The acid pump 203 will continue to add acid from the acid container 202 to the acidified water storage tank 201 until the sensor signal from the pH sensor 204 indicates that the acidified water in the acidified water storage tank 201 is at the desired the desired pH level.

The spraying system, thus arranged, ensures that the animal waste collected in the grated floor 101 is regularly sprayed with acidified water.

Along with reducing the harmful emissions to the atmosphere and removing harmful pollutants from the animal waste stored in the effluent pit 102, by spraying the animal waste with acidified water at the point that it is collected in an effluent pit On situ), when the slurry that is formed by the animal waste is later removed for use as a crop fertiliser it is "pre-treated" which means that it need not be treated as it is spread/injected during fertilizing operations.

The skilled person will understand that examples of the invention can be implemented in alternative ways to the specific example described with reference to Figure 1. In particular, there are many potential ways in which a suitable spraying system can be incorporated within an animal facility to spray an effluent pit with acidified water. For example, rather than the automatic replenishment of the acidified water storage tank 201 described above (facilitated by fresh water being provided from water inlet 206 and acid pumped from the acid container 202 under the control of the acid pump 203), the acidified water could be manually mixed and manually replenished. Similarly, rather than automatically controlling spraying operations with the valve control unit 210, the flow control valve 209 could be manually controlled. Further, the spraying means by which the acidified water is sprayed on the animal waste collected in the effluent pit 102 could be provided by a single nozzle or any suitable arrangement of nozzles rather than the nozzle array 103 comprising multiple nozzles depicted in Figure 1.

The skilled person will also understand that spraying systems in accordance with embodiments of the invention can be incorporated in any suitable facility comprising an effluent pit in which waste collects. For example, a spraying system in accordance with certain embodiments of the invention could be incorporated in a milk creamery facility to treat waste sludge from creamery processes collected in one or more effluent tanks located in the facility.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations).

It will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope being indicated by the following claims.

Claims

CLAIMS1. A facility comprising: an effluent pit in which waste from the facility collects, and a spraying system, wherein the spraying system is configured to spray acidified water in situ onto waste collected in the effluent pit via spraying means to reduce harmful emissions being emitted to the atmosphere from the collected waste.
2. A facility according to claim 1, wherein the facility is an animal housing facility for housing animals, and waste from animals housed in the facility collects in the effluent pit, wherein the spraying system is configured to spray acidified water onto waste collected in the effluent pit via the spraying means to reduce ammonia emissions from the collected animal waste when the animal waste is subsequently used as crop fertiliser.
3. A facility according to claim 1 or 2, wherein the spraying system further comprises an acidified water storing means configured to stored acidified water to be sprayed onto the waste collected in the effluent pit via the spraying means.
4. A facility according to claim 3, wherein the spraying system further comprises a flow control device for controlling flow of the acidified water from the acidified water storing means to the spraying means.
5. A facility according to claim 4, further comprising a control unit for controlling operation of the flow control device.
6. A facility according to claim 5, wherein the control unit is configured to control the flow control device so that the acidified water is sprayed onto the waste collected in the effluent pit periodically.
7. A facility according to claim 6, wherein the control unit is configured to control the flow control device so that the acidified water is sprayed onto the waste collected in the effluent pit periodically for a predetermined duration.
8. A facility according to claim 6 or 7, further comprising a gas sensor located in the vicinity of the effluent pit, said gas sensor configured to generate a sensor signal indicative of a concentration of one or more types of gas in the vicinity of the effluent pit and to communicate a corresponding sensor signal to the control unit, wherein the control unit is configured to control the flow control device to so that the acidified water is sprayed onto the waste collected in the effluent pit if the sensor signal indicates that the concentration of one or more gases in the vicinity of the effluent pit has exceeded a predetermined level.
9. A facility according to any of claims 3 to 8, wherein the spraying system further comprises: means to replenish the acidified water storage means with water from a water supply after acidified water has been sprayed onto waste collected in the effluent pit, and a pH monitoring unit for monitoring the pH of acidified water in the acidified water storing means and an acid pump, said pH monitoring unit configured to control the acid pump to pump acid from acid storage means into the acidified water storage means if the pH of the acidified water drops below a predetermined pH level.
10. A facility according to claim 9, wherein the predetermined pH level is approximately between 3 and 5.5.
11. A facility according to claim 9 or 10, wherein the acidified water storage means comprise a circulating pump to mix the water from the water supply with the acid from the acid storage means.
12. A facility according to any previous claim, wherein the acidified water storage means comprises a fluid storage tank.
13. A facility according to any previous claim, wherein spraying means comprises one or more nozzles.
14. A facility according to any previous claim, wherein the spraying means comprises an array of nozzles.
15. An animal housing facility according to claim 14 depending on claim 2, wherein the array of nozzles are located underneath a grated floor of the animal housing facility through which waste from animals housed in the facility passes.
16. A method of treating waste, said method comprising: collecting waste from a facility in an effluent pit forming part of the facility, and spraying the collected the effluent pit, in situ, with acidified water.
17. A method of treating animal waste according to claim 16, wherein the step of collecting waste comprises collecting animal waste from animals housed in an animal housing facility in an effluent pit forming part of the animal housing facility, and using the sprayed waste to produce fertiliser.
18. A spraying system for incorporating in a facility comprising an effluent pit in which waste from the facility collects, said spraying system comprising: spraying means for spraying acidified water onto waste collected in the effluent pit.