Waste storage cover

Abstract

A cover having a main sheet, at least one aperture, such as a fluid aperture, on a first surface side of the main sheet, and at least one ballast on the first surface side of the main sheet. A second aperture, such as a gas aperture, is provided on the second surface side. Additionally, the cover uses a plurality of ballasts, and in some instance, a mix of fluid-filled and gas-filled ballasts. A cover system can be formed by interconnecting a plurality of the covers.

Description

WASTE STORAGE COVERFIELD OF THE DISCLOSURE

[0001] This disclosure relates generally to waste storage covers and related systems and methods, and in particular, to rapidly deployable integrated anaerobic liquid and gas storage covers for the management of livestock, farm, and other liquid waste streams. Aspects of the designs enable automated mass manufacture, as well as the remediation of open waste lagoons or similar structures having a large surface area.BACKGROUND

[0002] Anaerobic digestion is a process that can be used to convert a wide range of biomass materials, in most cases, into mostly methane and carbon dioxide gases. Carbon dioxide (CO2) can be used for a variety of purposes such as food and industrial processing. Methane can be used as a direct replacement for fossil fuels such as oil and natural gas. When methane is generated from anaerobic digestion of organic matter (i.e., biomass), it is often referred to as “biomethane.”

[0003] Biomethane can be used as a fuel (e.g., for combustion engines or fuel cells) to provide power and heat. When biomethane is burnt, the exhaust typically comprises only carbon dioxide and water. In principle, the quantity of carbon dioxide released equals the amount that would have been released had the biomass been allowed to aerobically decompose naturally; therefore, methane produced in this way is effectively considered a zero-carbon fuel. The use of anaerobic digestion of biomass to produce methane is therefore seen as an effective way to reduce the level of carbon dioxide in the atmosphere and help to mitigate climate change. Patent publication WO 2022 / 013796, titled “Systems and Methods for Anaerobic Digestion,” describes, for instance, an anaerobic digester with a cover. As another example, patent publication WO 2023 / 152721 describes a cover for a slurry container, including attachment means.SUMMARY

[0004] According to embodiments, floating, modular, retrofit slurry covers for the exclusion rainwater and capture of biogas are provided, which can be manufactured using a layered construction. In certain aspects, a set of modular, tessellated covers are joined and can completely cover a range of slurry stores. The one or more covers can exclude rainwater from the store, reduce ammonia or other unwanted emissions, and capture the biogas. The collected rainwater and biogascan be extracted and repurposed as water and energy sources, respectively. Additionally, the use of flat pattern construction can increase potential manufacturing rate, reduces costs, and reduces complexity, thereby improving reliability.

[0005] According to embodiments, a cover is provided that comprises a main sheet, at least one aperture (e.g., a fluid aperture) on a first surface side of the main sheet, and at least one ballast on the first surface side of the main sheet. In some embodiments a second aperture (e.g., a gas aperture) may be provided on the second surface side. Additionally, the cover may use a plurality of ballasts, and in some embodiments, a mix of fluid-filled and gas-filled ballasts.

[0006] According to embodiments, a cover system is provided that comprises at least one cover. For instance, it may comprise a plurality of covers that are attached to each other.

[0007] According to embodiments, a method is provided. The method may comprise the steps of attaching one or more water aperture patches to a top side of a main cover sheet, and attaching one or more ballast tubes to the top side of the main cover sheet.

[0008] In certain aspects, a slurry lagoon, ring tank, or other waste container can be covered with a cover or cover system according to embodiments. This can include, for instance, remediation of an existing slurry pit or other open waste area.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments.

[0010] FIGs. 1A-1B illustrate an example of a floating cover design.

[0011] FIGs. 2A-2E illustrate a cover according to some embodiments.

[0012] FIGs. 3A-3C provide cross-sectional depictions of portions of a cover according to embodiments.

[0013] FIGs. 4A and 4B illustrate water and gas flow through apertures in covers and the systems of some embodiments.

[0014] FIG. 5 illustrates a cover according to some embodiments.

[0015] FIGs. 6A-6B illustrate a cover system according to some embodiments. FIGs. 6C and 6D provide design details relating to an anchor patch and connection element of someembodiments.

[0016] FIGs. 7-9 illustrate systems according to some embodiments.

[0017] FIGs. 10A-10B are flow charts showing processes according to some embodiments.

[0018] FIGs. 11 and 12 illustrate a covered slurry lagoon system with gas storage according to some embodiments.

[0019] FIGs. 13 A and 13B illustrate aspects of a connection element and tool according to some embodiments.

[0020] FIGs. 14A-14E illustrate a gas storage bag according to embodiments.DETAILED DESCRIPTION

[0021] There are currently certain challenges.

[0022] Liquid wastes, such as livestock slurries, are often stored in open lagoons. This can create many environmental issues, such as greenhouse gas emissions (e.g., methane, carbon, nitrous oxide, and often other noxious gases such as ammonia and hydrogen sulphide). Being open, such lagoons are subject to overfilling during intense rainfall, thereby diluting the waste and making it even more difficult to manage. Moreover, many lagoons are impractically large, which makes covering them technically difficult and expensive. This is further compounded during extreme weather conditions such as high winds, rainfall, snow, etc.

[0023] Even when a cover is used, there are still challenges. One complicating factor is that fresh water is denser than slurry and manure due to the latter typically consisting of water and 1-15% dry matter. During periods of high rainfall there is a tendency for water to build up above a rain cover, and this can form large puddles at any low spot. For large-area lagoons this can result in catastrophic failure if water from the entire surface flows to the lowest point. The increased mass of water in one area results with the puddle lowering itself into the slurry taking cover material with it. Eventually there is no material left and this results in tension building up which can result in the material tearing away from the edges of the lagoon. Another issue with large lagoons is that biogas bubbles get trapped under the cover, and in this instance, build up above the surface. This can result in excess material being lifted and tension building up ultimately resulting in failure of the cover restraints. Finally, for some covers, there may be a tendency to flap, whichcan lead to material fatigue and a loss of gas tightness.

[0024] Aspects of the disclosure and embodiments can provide solutions to one or more of these, or other challenges. Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0025] Referring now to FIGs. 1A and IB, an example of a floating cover design 100 is provided. In this example, a sheath is provided over a slurry lagoon 102, which acts to support air (108a, 108b) and water tubes (106a, 106b) providing ballast to the design. The sheath can further provide a path for gas 104 outlet. In some instance, one or more pipes or tubes may be used to extract 112 the biogas generated and trapped 110 under the cover 100. Additionally, rainwater that collects on the upper surface can be pumped away 114. As shown in FIG. IB, a rainwater moat may form around the air tubes on the upper surface. Such a design may be susceptible to certain issues. For instance, it is desirable that the biogas be removed through the space left between the gas cover and the air tube with a hose connection between adjacent tiles. Additionally, water could be removed from the center of each gas cover through a pump and floating shut-off valve. However, in some instances, the space between the air tube and the gas cover on the closest tile may be sucked closed, and there would be no pressure from the next tile to push fresh biogas around through the connecting pipe. Additionally, the rainwater handling approach is somewhat complex, and relies on a valve for each tile. This valve may be unreliable and prone to blockages or being held open by debris, meaning air would be sucked through, losing water flow. One or more of the embodiments described herein can provide improvements and advantages.

[0026] Referring now to FIGs. 2A-2D, one or more covers 200 according to embodiments are illustrated. In certain aspects, the covers may be adapted to cover a waste container, such as a slurry lagoon or other container (e.g., a steel ring tank). Additionally, they may be used to trap biogas produced under a cover.

[0027] As shown in FIG. 2 A, a cover 200 can be assembled with a main sheet (202). For instance, a square or rectangular tile of material with four sides, edges, and / or corners may be used. However, other shapes may be used as well, such as rounded (e.g., circular) covers. In this example, the cover 200 further comprises at least one water aperture 206 on a first side of the main sheet 202. The water aperture 206 can be formed, in embodiments, by edge-welding (204) orotherwise connecting a patch to the main sheet. The patch may be, for example, a rectangular patch of material. In this example, two apertures are provided on each side; however, different numbers and placements may be used.

[0028] As illustrated in FIG. 2B, a ballast 208a is also provided on the first surface side of the main sheet 202, and is located over the one or more apertures 206. This can provide a fluid- tight storage region comprised of a portion of the main sheet 202 and the materials that form the ballast’s upper and side surfaces. In embodiments, each of the apertures are located between the ballast and the main sheet. That is, the ballast 208a can be attached to the main sheet to form a fluid-tight seal for holding fluids; however, in the regions with the apertures 206, the aperture forms the seal with the ballast (e.g., acts as the bottom of the ballast instead of the main sheet). In this respect, the aperture can act as an outlet or tunnel that allows flow under the ballast even though the ballast is fluid-filled and integrated with the main sheet or other portions of the cover. This can provide gas or fluid flow off of (or onto) the cover 200, such as allowing the flow of collected rain water. According to embodiments, the cover 200 may also be provided with a skirt 214. The skirt may be used, for example, for the placement of connecting elements, to provide stability along an edge, to provide extra coverage, and to act as a platform for additional system components, among other uses. In certain aspects, the cover comprises at least one cover attachment element. It may be, for instance, a flexible interlocking connection. Other types may be used. In embodiments, a cover attachment element can be provided on each side / edge of the cover, for instance, along all 4 sides of a square or rectangular cover. Other arrangement may be used. While described as a water aperture in the example of FIGs. 2A-2D, element 206 can also be an aperture for the flow of other materials (e.g., other fluids or gases) according to embodiments.

[0029] Referring now to FIG. 2C, the cover 200 can also include one or more back-side features. For instance, the cover may have one or more additional ballasts 208b on the second surface side of the main sheet 202. According to embodiments, one or more of the front- and backside ballasts may be filled with water or another fluid. The weight of the material in the ballasts can provide stability, and in some instance, drop a portion of the cover below the surface level of the waste container or slurry lagoon. However, ballasts can also be filled with gas, such as air, for providing buoyancy depending on design needs. In some embodiments, a mixture of ballasts can be used. One example is described in connection with FIG. 5.

[0030] In certain aspects, one or more apertures 207 are provided on the second surface side of the cover 200. For example, the aperture 207 can allow for flow (e.g., fluid or gas flow) on the second surface side of the main sheet 202. In some embodiments, aperture 207 is formed between the second side additional ballast(s) 208 and the main sheet, which allows the aperture 207 to act as an outlet or tunnel on the second side. For instance, this arrangement could be used to enable gas flow (e.g., flow of biogas formed under the cover) to exit the cover for collection and / or processing. In the example of FIG. 2C, the gas aperture is provided at a corner of the cover 200. However, in some embodiments, it may be provided in a different location (e.g., side) of the cover. Similarly, although illustrated with a single aperture 207, cover 200 may use additional apertures 207 on the back side (e.g., on each edge). In some embodiments, the cover 200 may also include one or more anchor patches 209. They can be used, for instance, for connection to a rope or other system for placing, aligning, moving, and / or installing a cover 200. The anchor patch may comprise one or more holes or rings in embodiments. Additional details of an example anchor patch are provided in FIG. 6C. In some embodiments, the apertures 206, 207 can further include a pipe or other structural elements therein. The pipe or other element may be, for example, a perforated or mesh pipe or tube. The inclusion of such structural elements can help keep the aperture open to improve flow and provide stability.

[0031] As shown in FIG. 2D, like the apertures 206, the apertures 207 and ballasts 208a, 208b can be formed, in embodiments, by edge- welding (210a, 210b) one or more patches (e.g., rectangular patch(es) of material) to the main sheet. However, other shapes and connection techniques can be used. In some embodiments, one or more of the main sheet, the patch(es) that form the one or more apertures (e.g., for water or gas), and the material that forms the one or more ballasts are formed of a flat material. For example, all of these features may be manufactured by processing flat materials. In embodiments, the materials may comprise plastic or other polymers. An example of a cover according to some embodiments, having a water tunnel 250 and a ballast fill port 240, is depicted in FIG. 2E. The port 240 may be used, for example, for water.

[0032] FIG. 2D also shows the locations of cross-sections (A), (B), (C), which are further illustrated in FIGs. 3A, 3B, and 3C, respectively. As shown in FIG. 3A, the use of a top-side aperture under the ballast can form an exit or entry path 310. This may be, for instance, for flow of rainwater. As shown in FIG. 3B, in regions where there is no aperture, the cover 200 may be provided with top- and bottom-side ballasts. In this example, water ballast tubes 320 areillustrated. As shown in FIG. 3C, the use of a bottom-side aperture under the ballast can form an exit or entry path 330. The may be, for instance, for flow of biogas.

[0033] Referring now to FIG. 4A, an application 400 of a cover to a waste container is illustrated according to embodiments. In this example, a cover is applied over a slurry lagoon having a slurry level 450. The cover may be, for example, the cover 200 described in connection with FIGs. 2A-2E and 3A-3C above, cover 500, or one or more of the systems of FIGs. 6A-6B. As illustrated in FIG. 4A, biogas is generated under the cover, while rain collects on top of the cover. This can cause the cover to sink below the level of the slurry. In some embodiments, ballasts (water-filled ballasts in this example) may be used to control the sinking of the cover or otherwise provide stability for the installation. In the example of FIG. 4A, two covers 440A, 440B are connected by a flexible interlocking connection, such as described in connection with FIG. 13A, though other connection techniques may be used (e.g., snaps or welding). Additionally, while shown with two covers, the same principles can apply to a single-cover system. As shown in FIG. 4 A, although gas is generated under the cover (e.g., in the center) it is not trapped - it can exit via one or more of the biogas apertures 430. It can then be collected and / or processed. Likewise, although rainwater collects on the surface of the cover(s), it can move about due to the rainwater apertures 410. It can then be collected and / or processed, for instance, using a pump. Another example is provided in FIG. 4B, in which both air and water ballasts are used. In this example, there may be trapped biogas 470. Additionally, holes may be provided in the sheath to let rainwater through into channels between and around tiles, as indicated with the arrows of FIG. 4B.

[0034] FIG. 5 shows additional features that may be included on a cover 500 according to embodiments. The cover may, for instance, be a cover 200 that has the features described in connection with FIGs. 2A-2E and 3A-3C above.

[0035] In some embodiments, a plurality of ballasts can be used. This may include, for instance, a pair of ballasts 508 provided on the top side of the cover. In the example of FIG. 5, they are provided along the same edge of the cover, and the pair can be provided on every side of the cover. However, other arrangements can be used. Additionally, while shown as a pair, more than two (e.g., 3 or more) ballasts may be used. According to embodiments, at least one of the ballasts is fluid (e.g., water) filled and at least one ballast is gas (e.g., air) filled. As shown in FIG.5, even where multiple ballasts are used (including concentrically arranged ballasts) apertures may still be provided for fluid or gas flow. For instance, an aperture 506a may be located between a plurality of ballasts and the first surface side of the main sheet of cover 500. Multiple apertures may also be used. For instance, a first aperture 506c can be formed between a first ballast and the main sheet, and a second aperture 506b can be formed between a second ballasts and the main sheet. In this example, the first and second apertures 506b and 506c are arranged next to each other, such that one is for flow under an internal ballasts and the other is for flow under an external ballast. Although shown with one example of each of 506a, 506b, and 506c, embodiments include combinations of such designs as well as the use of multiple of each. This could allow, for instance, for flow through different locations or sides of the cover 500. Moreover, although illustrated with top-side designs, the multiple ballasts (e.g., pair 508) and apertures 506a, 506b, and 506c can also be implemented on the back side of cover 500. This could provide, for instance, gas flow (e.g., biogas from under cover 500) to enter / exit on the back side of the cover 500 through multiple ballast / aperture regions. As with the apertures described with respect to cover 200, the apertures of cover 500 may also be edge-welded according to embodiments. Cross-section AA shows ballasts in a region without apertures.

[0036] According to embodiments, one or more ballasts may be interconnected. In this respect, though separate ballasts, they can be filled as one, or share fill material. That is, two or more ballasts may be in fluid connection or in gas connection. This can simplify filling, for instance, by using a single fill port for multiple ballasts. One techniques for such interconnection is element 580, which is shown in FIG. 5 and cross-section BB. According to embodiments, the interconnection element 580 comprises one or more of a pair of holes (581) through the main sheet; an interconnection patch (583); and / or a connection tube (585), where the connection tube provides a fluid or gas connection between a first and second ballast of the cover. In this example, the connection occurs on a different side of the sheet than the side of the sheet where the ballast is located. While shown with a connection tube for stability, it may be omitted in some embodiments with flow through the fluid / gas path provided by the patch, holes, sheet, and ballasts layers. In some embodiments, the interconnection element is provided between every ballast of a given type (e.g., between all water ballasts and / or between all air ballasts). Details of potential placement of the interconnection element(s) are illustrated in FIG. 6D.

[0037] In some embodiments, one or more water channels 510 may be used. As shown inFIG. 5, a water channel can be formed by leaving a gap between two or more ballasts. While shown in the corner of cover 500, such channels may also be located on a side (e.g., centrally), on each side, in each corner, etc. Such channels can aid in the flow of collected rainwater, for instance, as illustrated in connection with FIG. 6A.

[0038] Referring now to FIGs. 6A, 6B, 7, 8, and 9, examples of a cover system 600, 650, 700, 800, and 900 are illustrated according to some embodiments. The systems may use, for example, covers 200 and / or 500 as described above. Additionally, features described in FIGs. 6A, 6B, 7, 8, and 9 can be combined according to embodiments.

[0039] As illustrated in FIG. 6A, one or more covers can be used in a system 600, such as a system for collecting rainwater, generating and collecting biogas, and / or generally covering a waste container, including covering an existing open slurry lagoon or a steel ring tank. In this example, four covers - labelled (1), (2), (3), and (4) - are used in the system 600. According to embodiments, the covers may be attached to one other. For instance, they may be connected using one or more cover attachment components along the edge of a cover 200, 500. In some embodiments a snap or interlocking connection is used; in some embodiments one or more of the covers are welded together. A heated roller may be used, for instance, for thermally welding covers or other edge connections (e.g., for apertures). Other connection techniques may be used. And as shown in FIGs. 6B, the ballasts of the multiple covers can also be interconnected with an external ballast linking element 691. The linking element may comprise, for instance, one or more pipes, tubes, and / or valves. In this respect, the ballasts of different covers can share ballast materials (e.g., water or air), which can simplify filling and maintaining ballast volume or pressure. In some embodiments, a fluid (677) and / or gas (679) port in at least one of the ballasts can be used. This can be used, for example, for maintaining a water or air pressure in the one or more ballasts. Further, a ballast fluid supply can be included. This may provide, for instance, a fixed pressure water supply to the ballasts, such as a fixed height tank.

[0040] In some embodiments, the system 600 comprises a skirt 614. The system may also comprise a pump 618. The pump may be, for instance, a submersible pump and it may be located on the skirt. In some embodiments, only a single pump is used to recover water collected on multiple covers. As depicted with the arrows shown on the cover system, water can flow off or onto one or more of the covers, across the system, be carried to the edge of the system, etc. Thisis accomplished, for instance, with flow via apertures (e.g., apertures 206, 506) and / or flow via water channels, such as channels 510 between ballasts of a given cover. Likewise, channels can be formed between the ballasts of neighbouring covers. In some embodiments, the water may be pumped away, for instance, for re-use in a secondary system. In embodiments where the covers are used to trap gas generated below the covers, one or more gas removal outlets or pipes 675 may be used. In some embodiments, only a single gas removal pipe or outlet is used for the system (e.g., wherein gas generated under a plurality of covers is collectively output in a single location). This may be accomplished, for example, by allowing gas to flow between different covers. This may be accomplished, for example, using gas apertures on the underside of the covers as described with respect to covers 200, 500.

[0041] In some embodiments, a submersible pump 618 can be positioned in a sump, such as a plastic container or barrel. In this example, the sump has holes in it to allow the rainwater to enter, where the holes are sized to prevent foreign debris (e.g., such as leaves, sticks, etc., on the rain cover) from entering the sump. That is, the sump holes can be used to filter out any debris too large for the pump to handle, and be of sufficient quantity to provide free flow of rainwater into the sump so that the pumping capability is not compromised. In some embodiments, the sump is weighted sufficiently so that it pushes the rain cover down into the slurry beneath, thereby creating a low point for the rainwater to flow to. By its nature, the sump (and hence the pump) thus becomes the lowest point on the rain cover, allowing the rainwater to flow to this common take-off point. One location for the sump is in the corner of the lagoon; however, other positions can be used.

[0042] Referring now to FIG. 7, a system 700 is illustrated according to some embodiments with two or more covers that are positioned over a waste container, which is a slurry lagoon in this example. Biogas 710a, 710b generated from the slurry 720 builds up under the two covers. Despite the presence over water build-up 730, the biogas is able to flow to the outside of the waste container. This includes, in embodiments, flow under the skirt 740. In this example, the gas is provided to a perforated pipe 750 or other gas outlet device. Additional details of the water locks, such as lock 770, are provided with respect to FIG. 8.

[0043] Aspects of a system 800 are shown in FIG. 8. The system 800 may be, for example, a cover system positioned over a waste container (e.g., a slurry pit) implementing one or morecovers described herein. In this example, a biogas water seal 810 or lock is illustrated. In some embodiments, a waste container - such as a slurry lagoon - may use a liner 850 below the waste material 860. The liner of the container can be connected to the skirt(s) 840 or other portion of the main sheet of the one or more covers over the container, thereby forming a gas- and / or fluid-tight connection. In certain aspects, an interlock 830 is provided. In embodiments, the connection may be made in a recess that contains water. One benefit of this arrangement is that if there is a leak, it will be visible as bubbles in the water. An additional benefit is that the water pressure acts to counteract the internal gas pressure, thereby balancing the pressure across the seal and making releases less likely and / or smaller. A more general benefit of the edge sealing is to capture and retain more of the methane / CO2 emissions from the waste container. In embodiments, a slurry pit or one or more aspects of the system 800 may be built into an earth bank 820.

[0044] While illustrated with a flexible interlocking connection, other connection techniques (e.g., welding) may be used. Also, while illustrated with an earth bank of a slurry lagoon, these same principles can apply to other waste containers, such as steel ring tanks.

[0045] Referring now to FIG. 9, a system 900 is illustrated according to embodiments. The system 900 may use, for instance, a cover 200, 500 and may implement one or more features described with respect to FIGs. 6-8. In this example, collection of rainwater and biogas are illustrated. In particular, biogas accumulates under one or more covers, and is removed via a gas float 955. For instance, the collected gas is provided to a gas removal pipe 965 from extraction and further processing. Additionally, rainwater can run offer the covers and move the edges. In some embodiments, it can then be pumped off (e.g., using a single submersible pump).

[0046] Referring now to FIGs. 10A and 10B, processes 1000 and 1080 are described according to embodiments. The process 1000 and 1080 can be used, for instance, for making or using covers 200 and 500, as well as the systems described with respect to FIGs. 6A, 6B, 7, 8, and 9.

[0047] The process may begin, in some embodiments, with preparing one or more of the ballast tubes, main sheet, and / or patches (slOlO, 1020). This can include, for instance, laying out the materials, cutting patterns for the sheet or other components, providing holes / ports for access or valve placement, etc. These steps may be optional, for example, where the starting materials are already provided. In step si 030, one or more water tunnel patches, such as apertures 206 or506, are attached to the top side of the main sheet. In step si 040, one or more ballasts tubes are formed, for instance, by attaching a ballast tube to the top side of the main sheet. This could include ballast 208, or a plurality of ballasts 508, in some embodiments. In some embodiments, attaching one or more water aperture patches to the top side of the main cover sheet includes attaching the patches at a center point on at least one side of the cover. In some embodiments, attaching one or more ballast tubes to the top side of the main cover sheet comprises attaching at least one fluid ballast tube and at least one air ballast tube (e.g., arranged in pairs on each side of the cover).

[0048] In some embodiments, a cover may also comprise backside elements. In such embodiments, step si 050 comprises flipping the main sheet (including any components thereon), and performing backside processing si 060. This could include, for example, assembling ballast connector patches (e.g., with tubes), adding bottom-side water or air ballasts, adding one or more ballast connector tubes, and adding one or more gas outlet patches, such as aperture 207. An example of the connector features 580 that may be used is provided in FIG. 5. In some embodiments, a gas tunnel outlet patch is provided at a corner of the main sheet. In step si 070, one or more connection elements may be setup. This could include, for example, connection elements as described in FIG. 13A, ballasts connection 691, gas take-off features (e.g., outlet 675), or gas and fluid ports (e.g., ports 677, 679). One or more pipes or tubes may be inserted into the apertures or connection elements in some embodiments (e.g., to maintain an opening).

[0049] According to embodiments, the covers 200, 500 may be assembled entirely from flat materials. For instance, each of the main sheet, the patch(es) that form the one or more apertures (e.g., for water or gas), and the material that forms the one or more ballasts are all formed of a flat (e.g., plastic) material in embodiments. Thus, one or more of steps slOlO, sl020, sl030, sl50, and sl060 can comprise the processing of flat (e.g., plastic or other polymeric) materials. In embodiments, attaching ballast tubes and / or aperture patches is performed with edge welding (e.g., thermos) of flat structures. One option for cutting is laser cutting; however, mechanical techniques may be used as well. In embodiments, cutting may be performed using an automatic computer- controlled process.

[0050] Referring now to FIG. 10B and process 1080, processes for interconnecting and using one or more covers and cover systems described herein are provided according toembodiments. The steps of process 1080 may follow, of instance, the steps of process 1000. The process 1080 may be, for instance, for making or using one or more of the systems described in connection with FIGs. 6A, 6B, 7, 8, and 9.

[0051] For systems using a plurality of covers, the process 1080 may begin with step si 081, in which a plurality of covers are interconnected. This could include, for instance, connections via welding or interlocking connection. In step si 082, a waste container, such as a slurry lagoon or other vessel, is covered with the one or more covers. According to embodiments, one or more of the steps (e.g., sl082) is performed to remediate a pre-existing slurry lagoon. In step 1083, one or more of the ballast ports are connected, and can be filled (e.g., with water or air). In certain aspects, filling the ballasts comprises maintaining a fixed gas or fluid pressure in the ballast. In step sl084, a water pump is connected (e.g., a single submersible pump). In step sl085, at least one gas take-off is connected. According to some embodiments, only a single biogas outlet is used for multiple cover elements. In step si 086, one or more of rainwater and biogas are removed from the system.

[0052] Embodiments described herein may refer to a cover for a lagoon. The cover can be used in a covered slurry lagoon system having: (i) a slurry lagoon, and (ii) a cover for the slurry lagoon. Embodiments also refer to the covered slurry lagoon system. In embodiments, the cover for the lagoon can be used with existing open slurry lagoons, to convert such open slurry lagoons into a covered slurry lagoon system.

[0053] According to some embodiments, the cover 200, 500, 600 may be formed at least in part of an expandable membrane configured to store gas, such as biogas generated in a lagoon or other waste storage container. For instance, a main sheet may have multiple layers, or an additional layer may be provided on the main sheet, to form a gas storage. Examples are discussed in connection with FIGs. 11 and 12. Additionally, the covers and gas storage techniques described in WO 2022 / 013796 are hereby incorporated by reference in their entirety.

[0054] FIG. 11 is a cross-sectional schematic illustrating a covered slurry lagoon system 1100 according to an embodiment. The covered slurry lagoon system 1100 includes a slurry lagoon 1102 having a bottom wall 1104 and side walls (or banks) 1106. The covered slurry lagoon system 1100 also includes a cover 1108. The cover 1108 may be an expandable membrane having a plurality of sections 1110. In embodiments, the sections 1110 may expand differently from eachother, for instance, some may stretch out more and some may stretch out less than others. The sections 1110 may be in a single row, or may include a number of different rows such that there is a matrix-like pattern of sections 1110. Where two sections 1110 come together (e.g., as shown at points 1111 and 1113), a rope 1112 and an elastic material 1114 are coupled to the cover 1108, extending between and attached to the points 1111 and 1113. The rope 1112 acts to limit expansion of the cover 1100. As gas fills the membrane and points 1111 and 1113 tend to be expanded, the rope 1112 becomes taut and prevents further expansion. The elastic material 1114 acts to compress the cover 1100. The elastic material 1114 pulls between points 1111 and 1113 and helps provide shape to the cover 1100. In some embodiments, the elastic material 1114 is a string of elastic, or a tubular elastic component, that extends between points 1111 and 1113 and compresses the membrane.

[0055] In embodiments, rope 1112 may be replaced with any restraining member that can limit or control the expansion of the expandable membrane. The restraining member may be coupled to the expandable membrane and configured to limit expansion of the expandable membrane, for example, in a similar manner to the rope 1112. In embodiments, elastic material 1114 may be replaced or otherwise implemented with any stretchable member that can compress the expandable membrane. The stretchable member may be coupled to the expandable membrane and configured to compress the expandable membrane, for example, in a similar manner to the elastic material 1114.

[0056] In embodiments, the covered slurry lagoon system 1100 also includes a skirt 1116 that surrounds the outer perimeter of the cover 1108. In the example of FIG. 11, the skirt is weighted so that it remains submerged within the slurry lagoon 1102. However, according to embodiments, the cover can be arranged (e.g., with ballasts) such that the outer portions are not submerged in the manner shown in FIG. 11. As an example, the gas storage of FIG. 11 can be implemented with covers and covers systems as shown in FIGs. 6A and 6B, FIG. 7, FIG. 8, and FIG. 9.

[0057] The covered slurry lagoon system 1100 may also include one or more gas inlets and gas outlets. For example, a gas outlet takes raw gas out of the slurry lagoon 1102 via piping 1118, e.g. through a valve in the skirt 1116, and allows the raw gas to be fed into gas processing system 1122. The processed gas can then be fed back into cover 1108 by a gas inlet via piping1120, e.g. through a valve in the cover 1108. In this way, the cover 1108 acts as a storage for processed gas from the slurry lagoon 1102. In embodiments, different types of gas (e.g., different purifications of carbon dioxide or methane) may be stored separately in cover 1108. For example, gas permeable / semi-permeable membranes may be used within cover 1108 to provide for different storage areas. In such cases, the membrane may be chosen so that the heavier gasses may be at the lower layers, and the lighter gasses may be allowed to rise through the permeable membranes, to appropriately segregate the different types of gas. Similarly, gas impermeable membranes may also be used within cover 1108 to provide for different storage areas. In such cases, gas processing system 1122 will have separate gas outlets for the different types of gasses that can then be directed to the appropriate storage areas. A gas processing system 1122 may include any of the gas processing systems disclosed herein.

[0058] The cover 1108 effectively acts as a storage space for gas. A mobile processing station may be used for recovering the gas that is stored in the cover 1108. The cover 1108 may also provide one or more of thermal insulation and thermal management, water collection and reuse, and / or energy recovery systems, such as described elsewhere herein.

[0059] In some embodiments, the cover 1108 may be made from a number of different materials, including one or more of polypropylene, polyethylene, polyether ether ketone (PEEK), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), and ethylene tetrafluoroethylene (ETFE). Exemplary trade-named materials include an XR-5 geomembrane and Sattler Pro-tex Polyplan composite. Covers 200, 500, including the ballast and patch elements, can likewise be made from any of these materials, though other materials (e.g., plastic or other polymers) can be used as well.

[0060] As shown in the example of FIG. 11, the cover 1108 is empty, meaning that it does not yet have any biogas from the slurry lagoon 1102 in it. In this case, the cover 1108 is in an unexpanded state. The right-most segment 1110 shown in FIG. 11 has a height hl in this unexpanded state. As shown in FIG. 12, the cover 1108 is full, meaning that it has reached its capacity of storing biogas from the slurry lagoon 1102. In this case, the cover 1108 is in an expanded state. The right-most segment 1110 shown in FIG. 12 has a height h2 in this expanded state. The height h2 is larger than hl, and the difference between h2 and hl represents an amount of expandability for the cover 1108. The amount of expandability may be controlled by the lengthof the rope 1112 in this embodiment. As will be explained, the expandability of different sections 1110 may vary in some embodiments. The amount of storage capacity of cover 1108 is proportional to the expandability of the different sections 1110.

[0061] As shown in FIG. 12, the end-most sections 1110 have rope 1112 and elastic material 1114 at the outer edges also, not just in the interior where two or more sections 1110 meet. In embodiments where this is the case, the outer edges of the expandable membrane are allowed to move as the amount of gas in storage empties and to pull in as the amount of gas in storage fills. The overall width and length of the membrane may drop to the position of the outermost elastic material 1114 and rope 1112 when the storage space is full.

[0062] Although FIGs. 11 and 12 illustrate a single cover, the same techniques can be implemented with multiple covers according to embodiments.

[0063] Referring now to FIG. 13 A, an interlocking connection 1300 is illustrated according to some embodiments. In this example, the cover connection element includes locking features that join the edges 1310, 1320 of two covers (e.g., covers 200, 500). In some embodiments, such a mechanism may be used to construct a cover system, such as system 600, 650. In embodiments, the locking mechanism is engaged by pushing the barbs 1330 of the first cover together with the barbs 1340 of the second cover. This may be done, for instance, using a vertical force that can be provided by two rollers positioned over the top and the bottom. In certain aspects, the rollers have recesses that guide the closing tool as it is pulled along the join. To allow this action and yet provide a good seal, a space is allowed either side of the barbs in some embodiments. Once closed, the horizontal force of the barb legs creates the seal. This interconnection process may be used as part of step si 081 in process 1080 described above.

[0064] According to embodiments, the profile of the interlock is designed so that it naturally locks into place when pushed together. To put the interlocking components together in a controlled way over long distances, a closing tool 1350 as shown in FIG. 13B may be used. In the example of FIG. 13B, the tool 1350 has two rollers - an upper roller 1361 and a lower roller 1362. The rollers are positioned above / below one another on an expandable frame 1370 that allows them to be pulled apart, for instance, in order to fit around the interlocking connection elements. The expandable frame 1370 can also be used to forced together the rollers 1361, 1362. In embodiments, this is accomplished by hand pressure or a screw press. The closing tool is thenpulled along the two interlocks (e.g., of the two edges 1310, 1320) with the guide rails pulling the two connections elements into alignment as it is pulled. As illustrated in the end view (AA) of the rollers 1361, 1362, flat rollers are used in some embodiments.

[0065] However, as illustrated in end view (BB), one or both of the rollers 1361, 1362 can be profiled so that they force the interlocking elements into an unnatural state at the point of closure, for example a ridge 1380 can be used to bend the two tines that form the jaws (e.g., barbs 1330, 1340) on one side of the of connection element into an open position. On the other roller, a corresponding depression or recess 1390 is positioned opposite the ridge that causes the two tines that insert into the jaws to come together so that they enter into the opened jaws. The profiling of the rollers can therefore cause the natural shape of the extruded interlock into an unnatural state at the position of closing. Once the rollers have passed over the closure point the tines of the flexible interlocking join are then left with lateral pressure acting on the jaw tines and locking tines. A liquid and gas tight seal can then be provided. Though described for use with covers 200, 500, the interlocking design 1300 and tool 1350 may be broadly used in other applications requiring gas- or fluid-tight seals according to embodiments.

[0066] Referring now to FIGs. 14A-14E, aspects of a storage bag (e.g., a biogas storage bag) 1400 are illustrated according to embodiments. The bag maybe used with the covers and system described in connection with the foregoing embodiments. For example, a storage bag may be provided on a cover 200, 500 or on a cover system 600, 650 according to some embodiments. In certain aspects, the storage bag may be used in place of the storage techniques described with respect to FIGs. 11 and 12; however, it may also be used in addition to the storage described in FIGs. 11 and 12. Gas may be provided to the storage bag 1400, for instance, via a gas inlet and / or removed via gas outlet. This could include, for instance a flange 1401 connected to a sidewall of the bag 1400. In embodiments, separate (or multiple) inlets and outlets may be used, though a single inlet / outlet may also be used. Though not illustrated in this example, a pipe or tube can be used in some instances for gas delivery and / or removal (e.g., to or from a gas processing system, such as shown in FIG. 11).

[0067] FIG. 14A shows a potential issue that can arise when using a gas storage bag 1400. As illustrated, the windward side gets the full force of the wind 1402 pushing it backwards and forwards. This movement over time will degrade the storage bag material’s ability to hold gas.

[0068] FIG. 14B shows a weighted perimeter solution according to embodiments, which comprises a weighted tube 1404. The tube may built into the bag’s perimeter, for example, on its upper edge. When the store is only partially filled, the edge is held close to the ground by the weight of the bag, thereby reducing its wind resistance dramatically. The rest of the store is still held under tension by the elastic tethers 1406, but the volume of gas needed to create the tension is greatly reduced as the sides are held close to the ground. Minimizing the volume at which the structure becomes stable is a benefit of embodiments. FIG. 14C shows that as the bag 1400 fills, each elastic tether provides tension up to the point where the rope tether 1408 is tight. In embodiments, only when all the rope tethers starting from the middle outwards are tight does the weighted perimeter finally rise from the ground. In this respect, the total storage volume can be retained. It may be possible that only a small quantity of gas is required for the weighted perimeter to finally be completely lifted into its uppermost position as shown in FIG. 14D. At this point the storage bag is fully inflated and tight and therefore less susceptible to high winds. FIG. 14E is a top view of an example of the bag structure. While illustrated with elastic members and ropes, some embodiments may omit one or more of these features. In some embodiments, a bag may be provided over a plurality of covers. In some embodiments, a bag may be provided for a single cover, including a single bag for each cover of a system.

[0069] According to embodiments, a cover is provided using a flat welded corner section. There are different types of thermal welds that can be formed between two polymer membrane materials. When making large sheets it is convenient to make all welds on a flat surface, such as a clean flat concrete floor. In some embodiments, the welds are formed using a combination of a hot air jet passed between the sheets followed by a uniform downward pressure. This can be provided by the mass of the machine, and an automatically controlled roller pushes the membranes together as it passes over the top. A combination of hot air temperature, machine mass, and roller speed can be optimised for different materials. A corner section can be used to add rigidity to the air tube frame or water ballast tube frame. In certain aspects, the corner is formed from two flat tapered sheets thermally welded on the main sheet. Two holes are positioned to allow water or air to flow around the tube. A simple flat panel is welded to the backside of the sheet creating a sealed chamber and providing a rigid structure. Finally, a small length of porous tube is inserted to keep the structure open when sucking air or water out of the frame.

[0070] According to some embodiments, a rain tunnel is provided. Robust rainwaterhandling is an important requirement for slurry store covers. Once rainwater has entered the slurry the storage volume is greatly reduced, and during intense rainfall accumulation of rainwater into puddles can put excessive loading onto the membrane. As the puddle grows, the higher density of fresh water over slurry causes the puddle to sink downwards as well as laterally. This pulls in any excess membrane that is incorporated to allow the slurry to rise and fall. As the puddle now becomes the lowest point, rainwater naturally finds its way there and this leads to the potential for catastrophic failure and the slurry lagoon cover becoming overwhelmed. To prevent the slurry cover from sinking due to the weight of the water ballast tubes, air flotation tubes can provide a counterbalancing force. However, as the air flotation tube is higher than the slurry level it also acts as a barrier to the rain from entering the channels between tessellations. This can become a significant problem for larger tessellations as water will tend to accumulate in the middle of a large flotation tube leading to puddles, which then become the lowest point and again can lead to large forces being put on the cover. To overcome this issue, some embodiments incorporate rain tunnels that run through the air flotation tubes positioned at regular intervals. These can be achieved using a simple planar welding process suitable for mass manufacture and the minimal part count.

[0071] According to some embodiments, rain movement is effectively accounted for in one or more designs. For large arrays of tessellations (e.g., as required for big slurry lagoons) rainwater must be removed from central tiles, otherwise an accumulation of fresh water builds up in the central area, which due to its higher density can result in puddles that grow in size until excessive force results on the membrane leading to catastrophic failure. The use of pumps or siphons can be used, but this involves the use of multiple take-off points that need to be serviced individually if a valve or pump fails. The use of rain tunnels coupled with the use of biogas tunnels can create natural run-off channels along the side of air flotation tubes. By creating a low point in the cover where a submersible pump or siphon point can be placed near the edge of the lagoon, the water over the entire cover surface naturally flows off of the biogas domes, through the rain tunnels or at the corner sections into the channels between tiles until it finds the pump or siphoning point. The use of valves or multiple pump or siphoning points can be removed in some embodiments.

[0072] According to embodiments, a biogas tunnel is provided. In some aspects, the biogas tunnel uses similar approaches as the rain tunnel but in reverse - using the buoyancy of the biogas, the design enables biogas movement between tiles and across the array through theincorporation of biogas tunnels. For example, pathways are created between the water ballast tubes and the membrane. The weight of the ballast tubes causes the biogas to be captured under the cover creating a dome. As more gas builds the water ballast tubes are raised slightly, but more importantly, the pressure under the dome causes the water level under the dome to drop slightly as well. This continues until a biogas tunnel entrance is exposed and a volume of gas escapes into the channel between the tiles. From here, as with the water, the only means of escape is to pass between the channels until it reaches the highest point near the edge of the lagoon where a biogas take-off vent if positioned. This can avoid the need for individual pipework from each tile, which would increase cost and complexity.

[0073] According to embodiments, covers are provided that can be mass manufactured. This can provide numerous advantageous over traditional, manual manufacturing techniques. In some embodiments, although the cover requires a three dimensional form in order to channel the rainwater and biogas, the cover is entirely planar in construction. In addition, the possibility of leaks across the slurry / air interface is dramatically reduced since apart from small holes within the flotation and ballast tubes, the design is fabricated from one simple sheet. The planar nature means that covers can be readily manufacture on a flat floor, and the light weight allows covers to be moved along the floor between operations. This provides the means for serial manufacturing using robotically controlled welding systems, greatly increasing production rate and reducing costs.

[0074] According to some embodiments, a water lock edge seal is provided. In certain aspects, biogas containment is ensured using a water seal around the perimeter of the lagoon. This uses a flexible interlocking seal between the lagoon liner and cover. Gas tightness and ground anchoring is achieved through a simple gutter system where the flexible interlocking seal is positioned at the bottom of a gutter filled with rainwater. The maximum pressure that can be achieved within the system is determined by the relative weight of the water ballast tubes.

[0075] According to embodiments, a design is provided whereby rainwater falling on a lagoon is safely transferred through a series of water tunnels to a pumping area using gravity, and biogas captured under the lagoon is transferred to a single take off point using gravity. That is, flow of gas and water are passive.

[0076] According to some embodiments, covers are joined immediately prior todeployment on the slurry lagoon, using either an extruded PVC joiner or thermo welding. A PVC ‘skirt’ is joined to outer perimeter of the cover group, covering the area of slurry between the edge of the lagoon and edge of the cover group. Anchor patches on the underside of the cover can facilitate the deployment and removal of covers. Once deployed, tubes fixed to the outer perimeter of the upper face of the cover(s) are filled with water ballast. The water ballast sinks below the level of the slurry, generating tension on the top of the cover. In embodiments, the tubes are linked via water tunnels on the underside of the cover by a compartment, held open by a perforated pipe insert. This facilitates filling (and emptying) of the tubes (e.g., 4 tubes), via a single point. During water filling, a second port on the opposite corner to the filling is left open to allow trapped air to escape. In some embodiments, the same arrangement is in place on a shorter set of tubes located nearer the centre of the cover than the water tubes. These can be filled with air and linked in the same way as the water tubes.

[0077] In some embodiments, four individual tubes or pairs of tubes are used. The reason four tubes are used is to form a gap in the corner of each cover. In addition, paths are created at the midpoint of each tube by bridge patches. Both these features allow rainwater to escape underneath or around the end of the tubes but on top of the cap, collecting in the skirt.

[0078] In some embodiments, a central float maintains the gas take off point above the level of the slurry, maintaining a gas path at all times. It also maintains tension on the cover prior to gas accumulation. This ensures rainwater runs off into the skirt and reduces material “cycling” in the wind. Rainwater collected in the skirt is pumped off. Some is reserved for use in the water ballast tubes, and the rest collected in a water store.

[0079] In certain respects, the safe and environmentally secure storage of livestock waste has become an urgent issue. Methane emissions from agriculture is now one of the most challenging problems from a climate change perspective, and the increase in extreme weather events means exacerbates the issues. Slurry run-off due to overflow of the store or the inability of saturated soils to absorb slurry (e.g., spread during the winter) leads to pollution of water courses and aquifers, in turn leading to the loss of valuable nutrients from soils. And when these nutrients enter the oceans they can produce dangerous blooms of algae. Moreover, many slurry lagoons were installed decades ago, which has resulted in a build-up of deep sediment on their floors. These sediments continue to produce biogas and other noxious gases, amplifying the greenhouse gasemissions issues. Over time many lagoons have been increased in size to cope with larger herd sizes and the increased rainfall - again exacerbating the challenges, including how to address larger lagoons. Embodiments described herein can address one or more of these issues.

[0080] Some embodiments include a structure that fixes the cover vertically through the use of a water ballast frame, which is heavier than the slurry. To prevent the water ballast from sinking into the slurry the ballast is counter balanced by air filled flotation tubes. A network of rain tunnels fabricated into the ballast and floatation tubes enable the rainwater to run off the cover and the biogas to rise to a common take off port. The structure enables minimal use of materials and can be realized through a mass-manufacture process. For instance, rolls of polymeric membrane can be combined with computer controlled membrane welders and cutters into a continuous process with, the end product rolled onto a drum for transportation. This increases the size of store that can be transported and deployed, limited only by the capability of the equipment and regional transportation regulations. This dramatically reduces cost and increases production and deployment capability, providing a solution to the ramp-up issues facing the industry due to the sheer volume of farms needing to upgrade their slurry and manure management infrastructure.

[0081] In some embodiments, a cover system is made up of identical tiles that can be readily deployed by filling the ballast tubes with air and floating them into position with each new tile being attached. A skirt adjoins the main cover area to the banks or sides of the slurry lagoon, and this is attached to the lower liner via an interlocking-type seal. The whole structure is rendered gas tight via a water seal.

[0082] Slurry and other wastes are typically 80-99% water with the remainder being organic material, which is generally less dense than water. This creates a natural buoyancy meaning the water ballast tubes only sink slightly ensuring the forces on the slurry cover are small. In some embodiments, the inclusion of air ballast ensures that the cover does not sink and also provides a counterbalancing action that holds the structure square.

[0083] Warm by geothermal heating once below a depth of 1 metre, the biological anaerobic digestion processes can be maintained at the same temperature as an open lagoon, which is known to host anaerobic bacterial cultures ensuring the continued breakdown of the volatile material before the digestate is reapplied to the soil. The resulting biogas can then be easily captured and stored in the biogas compartment positioned above the slurry store and with thesupport of a simple water filled ballast ring and cross member structure the biogas can be funnelled to take off extraction points. Moreover, rain is valuable commodity and this approach now encourages the capture of rainfall from building roofs and an increase in lake size providing the farmer with the ability to irrigate his land during times of drought.

[0084] In embodiments, the slurry and biogas are now completely sealed and can be expanded in size according to the farm’s need or the energy storage required. As the cost and convenience of deployment along with production capability has been dramatically increased, so to has the farmers ability to manage their slurry and capture fugitive methane and CO2.

[0085] Nutrient build up or reduction in soils is also now becoming a serious issue. For example, livestock feeds have been imported from overseas. This feed may be particularly rich in a particular nutrient and cannot be absorbed by the animal and so ends up in the slurry. There is therefore a resulting build up of, for example phosphorous, which ultimately ends up in the soil. The local pasture or crops cannot take up this nutrient, and so eventually, the phosphorous level in the soil builds up and then leaches into the water system contaminating drinking water. Aspects of the disclosure provide techniques for managing the slurries biological, physical and chemical properties such that excess nitrogen, phosphorous or potassium can be extracted as required, and then used to enhance the resulting slurry as required by the local soils or simply harvested as a mineral for sale into other markets. In certain aspects, there is a passive benefit to soil health as follows: by covering the slurry ammonia emissions are reduced; the nitrogen that would have been lost in the form of ammonia is retained within the slurry, meaning that more nitrogen is available to the soil when the slurry is applied.

[0086] Summary of Embodiments

[0087] Al . A cover (200, 500), comprising: a main sheet (202); at least one water aperture (206) on a first surface side of the main sheet; and at least one ballast (208a) on the first surface side of the main sheet.

[0088] A2. The cover of Al, wherein the water aperture is formed between the ballast and the main sheet.

[0089] A3. The cover of Al or A2, wherein the water aperture is formed by an edge- welded (204) patch on the main sheet, and / or wherein the ballast is formed by an edge- welded(210a, 210b) length of material on the main sheet.

[0090] A4. The cover of any of Al -A3 comprising: a plurality of ballasts (508) on the first surface side of the main sheet (e.g., along the same edge of the main sheet).

[0091] A5. The cover of A4, wherein a first ballast is a liquid (e.g., water) ballast and a second ballast is a gas (e.g., air) ballast.

[0092] A6. The cover of A4 or A5, wherein a ballast pair (e.g., water and air) is provided on each side of the cover (e.g., where the cover is square or rectangular in shape).

[0093] A7. The cover of any of A4-A6, wherein the at least one aperture (506a) is located between the plurality (e.g., pair) of ballasts (508) and the first surface side of the main sheet.

[0094] A8. The cover of any of A4-A6, wherein a first aperture (506c) is formed between a first inner ballast and the main sheet and a second aperture (506b) is formed between a second outer ballast and the main sheet (e.g., where the first and second ballasts are concentrically formed on the cover).

[0095] A9. The cover of any of A1-A8, wherein the cover further comprises: at least water channel (510), and optionally, wherein the water channel is located at a corner of the cover and is formed by two or more neighbouring ballasts.

[0096] A10. The cover of any of A1-A9, further comprising: at least one additional ballast (208b) on a second surface side of the main sheet (e.g., a water ballast).

[0097] Al l. The cover of any of A1-A10, further comprising: at least one gas aperture (207) on the second surface side of the main sheet.

[0098] Al 2. The cover of Al 1, wherein the gas aperture is formed between the second- side additional ballast and the main sheet.

[0099] Al 3. The cover of Al 1 or Al 2, wherein the gas aperture is formed by an edge- welded patch on the second surface side main sheet.

[0100] Al 4. The cover of any of Al 1 -Al 3, wherein the gas aperture is located in a corner of the cover (e.g., where the cover is a square or rectangle).

[0101] Al 5. The cover of any of Al -A14, further comprising an anchor patch (209)(e.g., for a rope connection).

[0102] Al 6. The cover of any of Al -Al 5 further comprising: a fluid (677) or gas (679) port in at least one of the ballasts (e.g., for maintaining a water or air pressure in the one or more ballasts).

[0103] Al 7. The cover of any of Al -Al 6, wherein a water or gas aperture comprises a tube (e.g., a perforated tube inserted into the aperture).

[0104] Al 8. The cover of any of Al -Al 8, further comprising: at least one ballast interconnection element (580).

[0105] Al 9. The cover of Al 8, wherein the at least one ballast interconnection element comprises one or more of:(i) a pair of holes (581) through the main sheet;(ii) an interconnection patch (583); and / or(iii) a connection tube (585), wherein the connection tube provides a fluid or gas connection between a first and second ballast of the cover.

[0106] A20. The cover of Al 8 or Al 9, wherein the interconnection element is provided between neighbouring ballasts (e.g., at each corner of the cover).

[0107] A21. The cover of any of A1-A22, further comprising: a gas outlet port (675) provided in the main sheet.

[0108] A22. The cover of any of A1-A21, further comprising: a skirt (214).

[0109] A23. The cover of any of A1-A22, wherein each of the main sheet, the patch(es) that form the one or more apertures (e.g., for water or gas), and the material that forms the one or more ballasts are all made of a flat (e.g., plastic) material.

[0110] A24. The cover of any of A1-A23, wherein the cover is adapted to cover a waste container (e.g., a slurry lagoon or other container).

[0111] A25. The cover of any of A1-A25, wherein the cover is adapted to trap a biogas produced under the cover.

[0112] A26. The cover of any of A1-A25, wherein the cover comprises a gas storageregion (e.g., where the cover comprising an expandable membrane (1108) or additional gas bag (1400) is provided on the upper surface of the main sheet).

[0113] A27. The cover of A26, wherein: the gas storage region comprises one or more stretchable and / or restraining members (1112, 1114, 1406, 1408); and / or the main sheet or gas bag comprises a semi-permeable membrane; the main sheet or gas bag comprises one or more inlet / outlet valves or openings; and / or wherein the gas bag 1400 comprises at least one weight (e.g., a weight tube (1404) at an edge of the bag).

[0114] A28. The cover of any of A1-A27, further comprising at least one cover attachment element (e.g., a locking element comprising one or more barbs and a space adjacent at least one barb).

[0115] A29. The cover of A28, wherein a cover attachment element is provided each side / edge of the cover (e.g., along all 4 sides of a square or rectangular cover)

[0116] A30. The cover of any of A1-A29, further comprising: at least one external ballast linking element (691) (e.g., for interconnecting the ballasts of the cover to the ballasts of a different cover).

[0117] A31. The cover of any of A1-A30, wherein:(i) the cover is round (e.g., circular);(ii) the waste container is a ring tank;(iii) the waste container is an over-ground contain; and / or(iv) the waste container is made from steel.

[0118] Bl. A cover system (600, 650, 700, 800, 900), comprising: at least one cover according to any of Al - A31.

[0119] B2. The cover system of Bl, comprising a plurality of covers according to any ofAl -A31, wherein the covers are attached to each other.

[0120] B3. The cover system of Bl or B2, further comprising one or more of:(i) a skirt (614);(ii) a pump (618) (e.g., a submersible pump);(iii) a sump (e.g., having a plurality of openings)(iv) one or more ballast connection links (691) (e.g., connecting the ballasts of a first and second cover);(v) one or more gas removal outlets or pipes (965);(vi) one or more ballast fluid supplies (e.g., a fixed pressure water supply);(vii) one or more water channel pathways on the upper surface of the cover system (e.g., formed by a plurality of ballasts on the plurality of covers);(viii) one or more gas floats (955) provided under one or more covers;(ix) a biogas water lock (e.g., formed by a connection between a skirt and a liner); and / or(x) one or more pipes (e.g., mesh pipes) inserted into a fluid or gas aperture.

[0121] B4. The cover system of any of B1-B3, wherein the at least one cover is arranged over a waste container (e.g., a slurry lagoon or other container).

[0122] B5. The cover system of B4, wherein the at least one cover is adapted to trap a biogas produced under the cover.

[0123] B6. The cover system of any of B3-B5, wherein only a single pump is used (e.g., wherein water collected from a plurality of covers is passed to a single pump).

[0124] B7. The cover system of any of B3-B6, wherein only a single gas removal pipe or outlet is used for the system (e.g., wherein gas generated under a plurality of covers is collectively output in a single location).

[0125] B8. The cover system of any of B1-B7, wherein a plurality of covers are welded together.

[0126] B9. The cover system of any of B1-B7, wherein a plurality of covers are connected using flexible interlocking connections or snap structures.

[0127] B10. The cover system of any of B1-B9, further comprising at least one gas storage bag 1400 (e.g., provided on the upper surface of one or more of the covers).

[0128] Bl 1. The cover system of B10, wherein: the gas storage bag comprises one or more stretchable and / or restraining members (1112, 1114, 1406, 1408); and / or at least one of the covers or the gas storage bag comprises a semi-permeable membrane; and / or wherein the gas bag comprises at least one weight.

[0129] Bl 2. The cover system of B10 or Bl 1, wherein a gas bag stores gas generatedunder a plurality of covers (e.g., a single bag is located over and stores gas from multiple covers).

[0130] Bl 3. The cover system of BIO or Bl 1, wherein each of a plurality of gas bags is attached to a single cover to store gas generated under that cover.

[0131] Cl. A method (1000), comprising: attaching (si 030) one or more water aperture patches to a top side of a main cover sheet; and attaching (si 040) one or more ballast tubes to the top side of the main cover sheet.

[0132] C2. The method of Cl, further comprising: preparing (sl020) the main sheet(e.g., laying out base material, cutting a cover pattern, cutting one or more corner holes, and / or preparing one or more gas outlets).

[0133] C3. The method of Cl or C2, further comprising: preparing (si 010) one or more components (e.g., one or more ballast tubes, one or more patches, and / or adding holes for ports / access).

[0134] C4. The method of any of C1-C3, further comprising: flipping (sl050) the main cover sheet to expose a second surface side; and performing (si 060) one or more backside operations.

[0135] C5. The method of C4, wherein the backside operations include one or more of:(i) attaching ballast connector patches;(ii) attaching ballast connector tubes;(iii) attaching one or more (e.g., water) ballast tubes; and / or(iv) attaching one or more tunnel patches (e.g., for gas outlet).

[0136] C6. The method of C5, wherein a gas tunnel outlet patch is provided at a corner of the main sheet.

[0137] C7. The method of any of C1-C6, wherein all cutting is performed using an automatic computer-controlled machine.

[0138] C8. The method of any of C1-C7, wherein attaching ballast tubes and aperture patches is performed with edge welding (e.g., thermos- welding) of flat structures.

[0139] C9. The method of any of C1-C8, wherein attaching one or more water aperture patches to the top side of the main cover sheet includes attaching the patches at a center point on at least one side of the cover.

[0140] CIO. The method of any of C1-C9, wherein attaching one or more ballast tubes to the top side of the main cover sheet comprises attaching at least one fluid ballast tube and at least one air ballast tube (e.g., arranged in pairs on each side of the cover).

[0141] Cl 1. The method of any of Cl -CIO, wherein the method is used to make a cover according to any of A1-A30.

[0142] C12. The method of any of Cl-Cl 1, further comprising:

[0143] connecting two or more covers together to form a system according to any of B l - B13.

[0144] DI. A method (1080), comprising: covering (si 082) a waste container (e.g., a slurry lagoon) with one or more covers according to any of A1-A31.

[0145] D2. The method of DI, further comprising: interconnecting (sl081) a plurality of covers according to any of A1-A31 (e.g., via welding or flexible interlocking connections).

[0146] D3. The method of DI or D2, further comprising: connecting or filling (si 083) one or more ballast ports or ballasts (e.g., with air or water).

[0147] D4. The method of D3, wherein filling the ballasts comprising maintaining a fixed gas or fluid pressure in the ballast.

[0148] D5. The method of any of D1-D4, further comprising: connecting (sl084) a water pump (e.g., a single submersible pump).

[0149] D6. The method of any of D1-D5, further comprising: connecting (sl085) at least one gas take-off (e.g., a single biogas outlet).

[0150] D7. The method of any of D1-D6, further comprising: removing (si 086) rain water and / or biogas from the one or more covers.

[0151] D8. The method of any of D1-D7, further comprising preparing at least one cover according to any of the steps of Cl -Cl 2.

[0152] D9. The method of any of D1-D8, wherein the method forms a system according to any of B1-B13.

[0153] DIO. The method of any of D1-D9, wherein the method is performed to remediate a pre-existing slurry lagoon.

[0154] Dl l. The method of any of DI -D10, wherein a plurality of covers are interconnected using a tool according to any of E1-E4.

[0155] El. A tool (1350), comprising: an expandable frame (1370); a first roller (1361) attached to the frame; and a second roller (1362) attached to the frame, wherein the first and second rollers are aligned opposite each other.

[0156] E2. The tool of El, wherein the first roller is positioned above the second roller.

[0157] E3. The tool El or E2, wherein at least one of the first and second roller comprises a ridge (1380) and at least one of the first and second rollers comprises a recess (1390).

[0158] E4. The tool of E3, wherein both the first and second roller each comprise a ridge and recess.

[0159] Fl. A method, comprising: interconnecting two or more structures using a tool according to any of E1-E4.

[0160] F2. The method of Fl, wherein the interconnecting comprises rolling the tool over a plurality of flexible interlocking connection elements (1300).

[0161] F3. The method of Fl or F2, wherein the two or more structures are covers according to any of Al - A31.

[0162] While various embodiments are described herein, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of this disclosure should not be limited by any of the above described exemplary embodiments. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[0163] Additionally, while the processes described above and illustrated in the drawingsare shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and some steps may be performed in parallel.

Claims

CLAIMS:

1. A cover (200, 500), comprising: a main sheet (202); at least one water aperture (206) on a first surface side of the main sheet; and at least one ballast (208a) on the first surface side of the main sheet.

2. The cover of claim 1, wherein the water aperture is formed between the ballast and the main sheet.

3. The cover of claim 1 or 2, wherein the water aperture is formed by an edge- welded (204) patch on the main sheet, and / or wherein the ballast is formed by an edge- welded (210a, 210b) length of material on the main sheet.

4. The cover of any of claims 1-3, further comprising: a plurality of ballasts (508) on the first surface side of the main sheet, wherein a first ballast is a liquid ballast and a second ballast is a gas ballast.

5. The cover of claim 4, wherein:(i) a ballast pair is provided on each side of the cover;(ii) at least one aperture (506a) is located between the plurality of ballasts (508) and the first surface side of the main sheet; and / or(iii) a first aperture (506c) is formed between a first inner ballast and the main sheet and a second aperture (506b) is formed between a second outer ballast and the main sheet.

6. The cover of any of claims 1-5, wherein the cover further comprises: at least water channel (510), and wherein the water channel is formed by two or more neighbouring ballasts.

7. The cover of any claims 1-6, further comprising: at least one additional ballast (208b) on a second surface side of the main sheet.

8. The cover of any of claims 1-7, further comprising: at least one gas aperture (207) on the second surface side of the main sheet.

9. The cover of claim 8, wherein the gas aperture is formed between the second-side additional ballast and the main sheet.

10. The cover of claim 8 or 9, wherein the gas aperture is formed by an edge- welded patch on the second surface side main sheet, and / or wherein the gas aperture is located in a corner of the cover.

11. The cover of any of claims 1-10, further comprising: a fluid (677) or gas (679) port in at least one of the ballasts for maintaining a water or air pressure in the one or more ballasts.

12. The cover of any of claims 1-11, wherein a water or gas aperture comprises a tube located within the aperture.

13. The cover of any of claims 1-12, further comprising: at least one ballast interconnection element (580), wherein the at least one ballast interconnection element comprises one or more of:(i) a pair of holes (581) through the main sheet;(ii) an interconnection patch (583); and / or(iii) a connection tube (585), wherein the connection tube provides a fluid or gas connection between a first and second ballast of the cover.

14. The cover of claim 13, wherein the interconnection element is provided between neighbouring ballasts.

15. The cover of any of claims 1-14, further comprising: a gas outlet port (675) provided in the main sheet.

16. The cover of any of claims 1-15, wherein each of the main sheet, the one or more patches that form the one or more apertures, and the material that forms the one or more ballasts are all made of a flat material.

17. The cover of any of claims 1-16, wherein the cover comprises a gas storage region.

18. A cover system (600, 650, 700, 800, 900), comprising: a plurality of covers according to any of claims 1-17, wherein the covers are attached to each other.

19. The cover system of claim 18, wherein the covers are arranged over a waste container and adapted to trap a biogas produced under the covers.

20. The cover system of claim 18 or 19, wherein the plurality of covers are connected using flexible interlocking connections or snap structures.

Images