Optimized vermifiltration bed for streamlined on-site construction

Abstract

A vermifiltration bed for on‑site construction is disclosed. The bed includes opposing wall sections each having a support post and a slotted wall panel, lateral drainage channels along outer sides of the wall sections configured for gravity discharge and exterior access for cleaning, and pallet‑type floor sections arranged above an impermeable layer to define a sub‑floor aeration and discharge space in fluid communication with the lateral drainage channels. Optional embodiments provide a sloped base without pallet‑type floor sections. Modular, reusable wall and floor sections enable rapid installation, maintenance from outside the bed, and improved oxygenation and drainage to reduce clogging. A method of on‑site construction, a wall‑section module, a floor‑section module, a kit, and a bed‑centric wastewater treatment system are also disclosed.

Description

OPTIMIZED VERMIFILTRATION BED FOR STREAMLINED ON-SITE CONSTRUCTION

[0001] This application claims the benefit of priority to provisional patent application US 63 / 690,395, filed on September 4, 2024, entitled “Optimized Vermifiltration Bed for Streamlined On‑Site Construction". The entirety of that application is incorporated herein by reference for all purposes to the extent permitted by applicable law.

[0002] The present disclosure relates to wastewater treatment. More particularly, it concerns vermifiltration beds and associated structures configured for on‑site construction and exterior maintenance access.

[0003] Vermifiltration is a biological treatment approach in which earthworms and associated microbiota process organics and solids within a filtration medium. Conventional bed constructions typically employ buried underdrain piping or gravel trenches beneath a continuous floor (see, e.g., WO2014205588A1). Such arrangements are difficult to access for inspection and cleaning, tend to accumulate fines, and promote anaerobic pockets that deteriorate treatment performance. In many installations, corrective maintenance requires partial demolition of the bed or full removal of the filtration medium to reach the underdrain network, resulting in prolonged downtime and high operating cost.

[0004] Other known implementations rely on monolithic concrete basins with internal channels or perforated slabs. While robust, these structures are capital‑intensive, slow to deploy, and poorly suited to redeployment or resizing when flows or sites change. Further, drain channels embedded within the footprint of the bed are commonly obstructed by media migration and biofilm accumulation, and external access for cleaning is limited or unavailable.

[0005] There remains a need for a vermifiltration bed architecture that: (i) provides exterior access for routine cleaning of drainage components without disturbing the filtration medium; (ii) enhances oxygen transfer to reduce the formation of anaerobic zones; (iii) simplifies on‑site construction using modular elements that can be installed, removed, transported, and reused; and (iv) supports safe operation with service‑path geometries for equipment access. Certain installations may additionally seek to document environmental co‑benefits (e.g., reduced methane generation associated with aerobic operation) within carbon accounting frameworks. Such contextual aspects may be described herein without being claimed.

[0006] According to one embodiment, the invention provides a vermifiltration bed comprising: a floor including an impermeable layer; a plurality of pallet‑type floor sections arranged above the impermeable layer to define a sub-floor aeration and discharge space; opposing wall sections along lateral sides configured to contain a filtration medium; and a drainage arrangement in fluid communication with the sub-floor aeration and discharge space and configured to evacuate treated effluent by gravity, the drainage arrangement being selected from (i) lateral drainage channels disposed along outer sides of the wall sections and accessible from outside the bed for cleaning, or (ii) centrally located drain structures disposed beneath the bed.

[0007] According to another embodiment, the pallet‑type floor sections comprise a slotted upper deck and a columnar lower portion that spaces the slotted upper deck above the impermeable layer. In certain embodiments, the slotted upper deck includes a lattice of crossing ribs defining rectangular openings, and the columnar lower portion includes a lattice of hollow standoff columns. In some embodiments, a permeable separator layer is disposed above the slotted upper deck to separate the filtration medium while permitting liquid flow and to cooperate with the pallet geometry in forming aeration channels. The floor sections may be arranged with a drainage gradient oriented either outward toward the lateral sides or inward toward a bed centerline.

[0008] According to another embodiment, the sub-floor aeration and discharge space communicates with the drainage arrangement through side or central openings defined by the interface between the floor sections and adjacent structures. In lateral-drain implementations, the drainage arrangement may comprise exposed gutters with removable covers and clean‑out ports, optionally integrated with curbs that support the wall sections; in central-drain implementations, the drainage arrangement may comprise drain inlet pipelines disposed beneath one or more central drain regions along the bed length, optionally including a primary drain inlet pipeline for normal operation and a secondary drain inlet pipeline located above the primary to provide redundancy in the event of blockage. In some embodiments, an open central channel with a protective grate is provided in lieu of pipelines, and in other embodiments closed conduits are used where site constraints favor subsurface conveyance. An effluent collection manifold can be hydraulically connected to the drainage arrangement and may be located between parallel beds.

[0009] According to another embodiment, the wall sections provide lateral containment of the filtration medium and may include wall panels that are continuous or slotted depending on the selected drainage arrangement. In certain lateral-drain embodiments, each wall section comprises a support post and a slotted wall panel arranged to retain the filtration medium while allowing treated effluent to pass laterally; in some cases the slotted wall panel comprises parallel elongate members arranged to define inter‑member slots (e.g., a wedge-wire type panel), and can include a lower inwardly canted baffle portion to inhibit media migration and a lower sealing strip configured to interface with the impermeable layer. In certain embodiments, the wall panels are removably fastened to support posts anchored to footings, enabling replacement without disturbing the footings.

[0010] According to another embodiment, the floor sections are polymer pallet‑type units having interlocking edges and lift points to enable installation, removal, and reuse. In some embodiments, the impermeable layer comprises a geomembrane liner over a compacted clay sub‑layer. In certain embodiments, vent openings provide gaseous communication between the sub-floor aeration and discharge space and ambient air to enhance aerobic conditions within the vermifiltration bed. In some embodiments, the wall sections and floor sections are modular and reusable, being configured for removal from a first installation site and re‑installation at a second installation site. In certain embodiments, the architecture is reconfigurable, allowing a bed installed in lateral-drain form to be converted to central-drain form (or vice versa) by exchanging drainage components and adjusting slope orientation while retaining wall and floor modules.

[0011] According to another embodiment (lateral-drain embodiment), the drainage arrangement comprises lateral drainage channels disposed along outer sides of the wall sections, configured for gravity discharge and exterior access for cleaning, with the sub-floor aeration and discharge space in fluid communication with each lateral drainage channel via openings formed between the floor sections and the wall sections. In certain embodiments, each lateral drainage channel is integrated with a concrete curb that supports the support posts of the corresponding wall section.

[0012] According to another embodiment (central-drain embodiment), the floor defines a drainage slope inwardly toward one or more central drain regions distributed along the bed length, and treated effluent is received by drain inlet pipelines arranged beneath each central drain region and hydraulically connected to a downstream collector. In some implementations, a primary drain inlet pipeline receives and directs effluent under normal operation and a secondary drain inlet pipeline is positioned above the primary to provide redundancy in the event of blockage. In other implementations, an open central channel with a protective grate is provided in lieu of pipelines. The pallet‑type floor sections, sub-floor aeration and discharge space, and wall sections remain as described above.

[0013] According to another embodiment, the invention provides a vermifiltration bed in which the floor includes an impermeable layer defining a drainage slope toward the drainage arrangement, thereby providing gravity evacuation without pallet‑type floor sections while maintaining exterior or underside access for cleaning. In certain embodiments, a permeable separator layer is disposed directly above the impermeable layer. In some embodiments, the drainage slope directs treated effluent toward lateral drainage channels or toward the central drain regions along substantially the entire length of the vermifiltration bed.

[0014] According to an additional embodiment, the invention provides a method of on‑site construction comprising: laying the impermeable layer; installing the drainage arrangement selected from (i) lateral drainage channels along outer sides of wall locations, or (ii) centrally located drain structures beneath the bed (including primary and secondary drain inlet pipelines at each central drain region, or an open central channel); anchoring the support posts and mounting wall panels to form the wall sections; placing the pallet‑type floor sections above the impermeable layer so as to establish the sub-floor aeration and discharge space in fluid communication with the selected drainage arrangement; and placing a permeable separator layer above the floor sections. In certain implementations, the method further comprises forming a service path extending between the opposing wall sections and dimensioned to permit operation of maintenance equipment; installing polymer pallet‑type floor sections having interlocking edges and lift points to enable removal and reuse; providing vent openings from the sub-floor aeration and discharge space to ambient air; and installing removable covers and clean‑out ports on lateral drainage channels or inspection points for central drain structures.

[0015] According to a further embodiment, the invention provides a modular wall section for a vermifiltration bed including a support post configured for anchoring to a footing and a wall panel removably fastened to the post, the wall panel being continuous or slotted to suit the selected drainage arrangement and configured to retain the filtration medium while allowing, where applicable, passage of treated effluent. In certain embodiments, a slotted wall panel comprises parallel elongate members arranged to form a wedge-wire type panel and includes a lower sealing strip to interface with the impermeable layer.

[0016] According to yet another embodiment, the invention provides a floor section for a vermifiltration bed including a slotted upper deck and a columnar lower portion configured to space the slotted upper deck above the impermeable layer to define the sub-floor aeration and discharge space. In certain embodiments, the floor section is a polymer pallet‑type unit having interlocking edges and lift points to enable installation, removal, and reuse.

[0017] According to another embodiment, the invention provides kits for constructing a vermifiltration bed, the kits including: (i) for lateral-drain installations, multiple wall sections, multiple floor sections, and at least one lateral drainage channel assembly with removable covers and clean‑out ports accessible from outside the bed; and (ii) for central-drain installations, multiple wall sections, multiple floor sections, drain inlet pipelines for each central drain region (including primary and secondary pipelines) or an open central channel with a protective grate, access points for inspection and flushing, and manifold connections to an underground collector—each kit further including fasteners and instructions for on‑site assembly.

[0018] According to another embodiment, the invention provides a wastewater treatment system including a distribution header configured to deliver influent onto a filtration medium contained within the vermifiltration bed and an effluent collection manifold hydraulically connected to the drainage arrangement, whether lateral drainage channels or centrally located drain structures.

[0019] Conventional vermifiltration beds and analogous biofiltration structures often employ buried underdrain piping or internal channels beneath the treatment footprint. Such arrangements are difficult to access for inspection and cleaning; accumulate fines and biofilm that impede flow; and promote anaerobic pockets that degrade treatment performance. Monolithic concrete basins are capital‑intensive, slow to deploy, and poorly suited to resizing or redeployment as flows or sites change. Maintenance commonly requires removal of filtration media to reach clogged drains, resulting in extended downtime and safety risks for operators. There is a need for a bed architecture that enables exterior access to drainage components, improves oxygen availability within the bed, simplifies on‑site construction using modular elements, and supports safe operation with service‑path geometries for equipment access, while maintaining robust containment over an impermeable layer.

[0020] The invention addresses these needs by providing a vermifiltration bed with: (i) opposing wall sections each having a support post and a slotted wall panel that retains the filtration medium while allowing treated effluent to pass; (ii) alternative drainage architectures, namely: lateral-drain channels disposed along outer sides of the wall sections, configured for gravity discharge and exterior cleaning access; and a central-drain arrangement in which the floor slopes inward and drain inlet pipelines beneath the bed receive the treated effluent and convey it to a collector, optionally with primary / secondary pipelines for blockage redundancy; and (iii) pallet‑type floor sections arranged above an impermeable layer to create a sub-floor aeration and discharge space in fluid communication with the selected drainage architecture. The bed employs modular, reusable wall and floor sections; may include venting to sustain aerobic conditions; and accommodates service‑path access for equipment.

[0021] Implementations of the disclosed architecture can provide one or more of the following effects without limiting the scope of the claims: (a) exterior cleaning of drainage channels without disturbing the filtration medium (lateral-drain variant), reducing downtime and labor; (b) enhanced oxygen transfer via the aerated sub-floor space, mitigating anaerobic zones and associated odors; (c) improved hydraulic reliability and reduced clogging due to gravity discharge into externally accessible channels or redundant central drain inlet pipelines; (d) accelerated on‑site construction and redeployment through modular, reusable wall and floor sections; (e) safer operation and maintenance via a defined service path and flushing access to the underside of the bed; (f) adaptability to site constraints by selecting lateral-drain where corridor space is available or central-drain where reduced footprint is required (eliminating lateral concrete channels can reduce inter‑bed spacing to service paths and a berm); (g) reduced overall use of concrete by concentrating structural concrete in drainage channels or local curbs while employing modular components elsewhere; and (h) potential environmental co‑benefits associated with sustained aerobic conditions.

[0022] The accompanying figures are provided for illustrative purposes only and are not intended to limit the scope of the invention in any way. They represent exemplary configurations that help to explain the principles and benefits of the invention.Fig.1

[0023] is a perspective view of a portion of the modular vermifiltration bed (100), illustrating the filtration medium, a floor section (140), and a wall section (120) including support posts (122), slotted wall panels (124), and lateral drainage channels (130).Fig.2

[0024] is a transverse cross‑section of the vermifiltration bed (100) showing a drainage slope implemented to facilitate gravity circulation of wastewater under treatment.Fig.3

[0025] is a longitudinal cross‑section of the vermifiltration bed (100) showing the wall sections (120) and their arrangement relative to the floor sections (140).Fig.4

[0026] is a detail view of a wall support post (122) according to an embodiment of the invention.Fig.5

[0027] is a plan (top) view taken along section A–A of the support post (122) of.Fig.6

[0028] is a perspective view of the support post (122) and the slotted wall panel (124).Fig.7

[0029] is a plan view of two parallel beds configured for central-drain operation, illustrating inward slopes toward centrally located drain regions with primary drain inlets (160), secondary drain inlets (162), and associated drain inlet pipelines (170, 172), and indicating section lines A, B, C, and D.Fig.8

[0030] (Section A) is a transverse cross‑section taken at a central drain region of a bed, showing convergence of the floor slopes toward the primary drain inlet (160) and secondary drain inlet (162), which discharge to primary and secondary drain inlet pipelines (170, 172).Fig.9

[0031] (Section B) is a transverse cross‑section taken between central drain regions of a bed, showing the inward slope of floor sections toward the bed centerline where no drain inlet is present.Fig.10

[0032] (Section C) is a longitudinal central detail showing the primary drain inlet (160) and secondary drain inlet (162) arranged vertically to provide redundancy and their connection to the primary and secondary drain inlet pipelines (170, 172).Fig.11

[0033] (Section D) is a longitudinal lateral detail taken away from a central drain region, showing the inward slope of the floor sections toward the bed centerline.Fig.12

[0034] is a schematic view of an underground collector (180) disposed between beds for conveying treated effluent from the drain inlet pipelines (170, 172) to downstream treatment or discharge.Fig.13

[0035] is a perspective view of the support post (122) and the continuous wall panel (126) installed in a vermifiltration bed (100).

[0036] Definitions

[0037] As used herein and in the claims, the following terms have the meanings indicated:Vermifiltration bed (100): a structural assembly configured to contain a filtration medium and earthworms for treatment of influent, independent of the particular medium composition.Floor section (140): a pallet type unit having a slotted upper deck (142) and a columnar lower portion (144) that spaces the upper deck (142) above the floor to define a sub-floor aeration and discharge space (146).Sub floor aeration and discharge space (146): a flow and gas exchange plenum defined between the impermeable layer (112) and the slotted upper deck (142) of the floor sections.Impermeable layer (112): any layer intended to inhibit downward liquid percolation, such as a geomembrane liner and / or compacted clay.Permeable separator layer (150): a porous layer placed above the slotted upper deck (142) to separate the filtration medium from the deck while allowing liquid flow; in cooperation with the pallet geometry it can form aeration channels.Wall section (120): a structural section along a lateral side of the bed comprising at least one support post (122) and a wall panel fixed to the post. The wall panel may be continuous (for containment) or slotted depending on the drainage arrangement. Where slotted, it may correspond to a slotted wall panel (124) as depicted in FIGS.1–6; where continuous, it may correspond to a continuous wall panel (126) used in central-drain embodiments, which can be of a treated wood or equivalent.Slotted wall panel (124): a panel having openings that allow passage of liquid while retaining the filtration medium, including slots, perforations, or spaces between elongate members (e.g., wedge-wire type).Continuous wall panel (126): a panel without through-slots, used to contain the filtration medium where lateral liquid passage is not required (e.g., central-drain embodiments).Lateral drainage channel (130): an elongate trough located along an outer side of the bed, configured for gravity discharge and accessible for cleaning from outside the bed.Drainage arrangement: a structure hydraulically coupled to the sub-floor aeration and discharge space (146) and configured to evacuate treated effluent by gravity, selected from lateral drainage channels (130) or centrally located drain structures beneath the bed.Central drain region: a region along the bed centerline where the floor slopes inward and treated effluent is received by centrally located drain structures.Primary drain inlet (160) / Secondary drain inlet (162): point drains located at a central drain region, with the secondary positioned above the primary to provide redundancy.Primary drain inlet pipeline (170) / Secondary drain inlet pipeline (172): pipelines disposed beneath a central drain region to receive treated effluent from the corresponding drain inlet(s), the secondary pipeline being positioned above the primary to provide redundancy.Underground collector (180): a subsurface manifold or conduit disposed between beds and configured to receive treated effluent from drain inlet pipelines and convey it downstream. The collector (180) comprises an overflow pipeline (182) to redirect overflow effluent if necessary, as depicted in.Service path: a central path dimensioned to permit transit and operation of maintenance equipment.

[0038] OVERALL ARCHITECTURE

[0039] The vermifiltration bed (100) is configured for streamlined on‑site construction, exterior maintenance access, and enhanced aeration and drainage. In a representative lateral-drain embodiment (Figs.1–3), opposing wall sections (120) bound a treatment footprint supported by pallet‑type floor sections (140) arranged above an impermeable layer (112) to define a sub-floor aeration and discharge space (146). Lateral drainage channels (130) disposed along outer sides of the wall sections (120) receive treated effluent by gravity and are accessible for cleaning from outside the bed. As shown in, the perimeter of the bed (100) may be bordered by an access road—either an inter‑bed road where multiple beds are installed or a perimeter road to facilitate installation and servicing.also illustrates that the bed end may include an end-of-bed roll curb and that a drain inlet can be provided at the distal end of the lateral drainage channels (130) to receive treated effluent and direct it to a designated discharge or collection point. The filtration medium placed in the bed may include wood chips.

[0040] In a representative central-drain embodiment, the structure of the wall sections (120), support posts (122), and pallet‑type floor sections (140) remains as described above; however, the wall panels are continuous (126) for containment and the floor is sloped inward toward a central drain region. Treated effluent converges toward the center and is received by a primary drain inlet (160) and a secondary drain inlet (162) located above the primary, which discharge to a primary drain inlet pipeline (170) and a secondary drain inlet pipeline (172) beneath the bed and are conveyed to a collector. The underside of the bed remains accessible (e.g., for flushing) because the floor sections (140) and posts are exposed, similar to the lateral-drain configuration. By removing lateral concrete channels, the central-drain embodiment can reduce inter‑bed spacing to service paths and a berm, enabling a reduced footprint installation.

[0041] FLOOR AND IMPERMEABLE LAYER (112)

[0042] A floor includes an impermeable layer to inhibit downward percolation. The impermeable layer (112) can be a geomembrane over compacted clay, or a monolithic liner supported by a prepared subgrade (110). The floor may be substantially level or established with a drainage gradient (e.g., 0.5%–2%) directed either outward toward the lateral drainage channels (130) or inward toward the bed centerline. Height‑adjustable shims may be used beneath floor sections (140) to fine‑tune the gradient. In lateral-drain installations, the transverse section is substantially constant along the bed length except at end transitions. In central-drain installations, the floor forms a basin‑like (concave) profile toward the centerline, implemented by arranging planar floor sections at progressively inward slopes around each central drain region. In an illustrative central-drain design, outer‑edge floor modules are set at about 12.7% slope toward the bed interior, transitioning to about 3% which is maintained to the center; multiple central drain regions may be distributed along long beds.

[0043] illustrates an example outward drainage gradient of approximately 3% directing treated effluent toward the lateral drainage channels (130) in a bed (100). In the embodiment of, the bed has a width of approximately 60 feet between wall sections (120) and an internal height of approximately 3 feet. The embodiment of(Section B of) illustrates a bed configured for central-drain operation with two gradients at a transverse cross-section: approximately 12.7% at the lateral edges of the bed and approximately 3% toward the centerline. Alternatively, multiple gradients may be implemented along the bed length, as shown in(Section D of), where longitudinal slopes of approximately 15%, 6.7%, and 0.5% are employed from an end of the bed towards the center.

[0044] WALL SECTIONS (120, 122, 124, 126)

[0045] Each wall section (120) includes a support post (122) and a wall panel configured to contain the filtration medium. The wall panel may be continuous (126) for containment (e.g., central-drain embodiments) or slotted (124) to facilitate lateral effluent passage (e.g., lateral-drain embodiments). In the slotted implementation depicted in Figs.1–6, each wall section includes a slotted wall panel (124) fastened to the support post (122). The slotted wall panel (124) retains the filtration medium while allowing treated effluent to pass laterally. In some embodiments, the panel (124) is a wedge-wire type panel comprising parallel elongate members forming inter‑member slots, with a nominal slot width selected to retain the chosen medium. The panel (124) may include a lower inwardly canted baffle portion to inhibit migration of the filtration medium toward the panel, and a lower sealing strip interfacing with the floor to inhibit bypass leakage. Support posts (122) can be anchored to discrete footings or to a curb integrated with the lateral drainage channels (130). In certain constructions, a base of the support post (122) is received within a recess of the curb or channel. In some embodiments, the support posts (122) include parallel welded plates (125) between which the slotted wall panel (124) is received and secured. In some embodiments, the support posts are made of concrete.

[0046] LATERAL DRAINAGE CHANNELS (130) — LATERAL-DRAIN EMBODIMENT

[0047] Lateral drainage channels (130) are arranged along outer sides of the wall sections (120) and are in fluid communication with the bed (100). The channels (130) are configured for gravity discharge and preferably include removable covers and clean‑out ports accessible from outside the bed. The sub-floor aeration and discharge space (146) communicates with the channels (130) through side openings located at interfaces between the floor sections (140) and the wall sections (120). An effluent collection manifold may be hydraulically connected to the channels (130) for conveyance to downstream treatment or discharge. While exposed lateral channels are preferred for ease of inspection and cleaning, closed conduits may alternatively be employed where site constraints require.

[0048] CENTRAL DRAIN INLET PIPELINES — CENTRAL-DRAIN EMBODIMENT

[0049] In the central-drain embodiment, one or more central drain regions are provided along the bed length. At each central drain region, a primary drain inlet (160) and a secondary drain inlet (162) are provided, the secondary being positioned above the primary to provide redundancy. The drain inlets discharge to a primary drain inlet pipeline (170) and a secondary drain inlet pipeline (172) disposed beneath the bed at or near the centerline to receive the converging treated effluent and convey it to a collector (180). The pipelines may include access points for inspection and flushing. The underside of the bed remains accessible for maintenance operations.

[0050] FLOOR SECTIONS AND SUB-FLOOR SPACE (146)

[0051] Floor sections (140) are pallet‑type units each including a slotted upper deck (142) and a columnar lower portion (144) that forms the sub-floor aeration and discharge space (146) above the impermeable layer (112). In one construction, the slotted upper deck (142) comprises a lattice of crossing ribs defining rectangular openings, and the columnar lower portion (144) comprises a lattice of hollow standoff columns. Interlocking edges and lift points facilitate installation, removal, and reuse. The floor sections (140) can be arranged to provide a drainage gradient toward the lateral drainage channels (130) or toward the central drain region, as applicable. A permeable separator layer (150) may be placed above the upper deck to separate the filtration medium while permitting flow. Vent openings may provide gaseous communication between the sub-floor space (146) and ambient air to sustain aerobic conditions. The combination of the pallet‑type floor sections and the permeable separator layer (150) creates aeration channels that enhance oxygen supply, which is beneficial for earthworm survival and sustained treatment performance.

[0052] SERVICE PATH

[0053] A service path extends longitudinally between the opposing wall sections (120) and is dimensioned to permit entry and operation of maintenance equipment such as irrigation rigs, tilling implements, or media‑handling tools. The bed layout can comprise two lateral filtration surfaces separated by the central service path, which facilitates assembly and vermicompost removal operations. In central-drain installations, elimination of lateral concrete channels can allow reduced inter‑bed spacing limited primarily to service paths and a berm; plan layouts may include multiple central drain regions per bed, with service corridors maintained between parallel beds.

[0054] OPERATION

[0055] During operation, influent is distributed onto the filtration medium, e.g., by a distribution header or sprinklers. Liquid percolates through the medium and across the permeable separator layer (150) toward the slotted upper deck (142). Fines and biofilm that pass through the separator layer drop into the sub-floor aeration and discharge space (146), where flow is channeled by gravity toward the lateral drainage channels (130) or toward one or more central drain regions, depending on the selected slope orientation. The aerated sub-floor space (146) promotes oxygen transfer to the lower regions of the medium and reduces formation of anaerobic pockets. The underside of the bed is accessible for flushing and inspection in both variants.

[0056] CLEANING AND MAINTENANCE

[0057] In the lateral-drain embodiment, the exterior placement of the lateral drainage channels (130) allows routine inspection and cleaning via removable covers and clean‑out ports without disturbing the filtration medium. In the central-drain embodiment, the centrally located drain inlet pipelines can be accessed via inspection points, and the exposed underside permits flushing operations. In embodiments with pallet‑type floor sections (140), individual sections can be lifted using the provided lift points to access the sub-floor space (146) if needed. The wall sections (120) are modular; slotted wall panels (124) can be removed from support posts (122) for replacement. Besides, the sub-floor space 8146) is sufficient to allow external flushing from the lateral ends of the bed.

[0058] In central-drain implementations, anti‑fouling measures can include periodic flushing of the drain inlet pipelines and the use of removable strainers at access points to intercept coarse solids. In embodiments employing an open central channel with a protective grate, the channel can be cleaned by lifting the grate and removing accumulated solids using standard tools. In embodiments with pallet‑type floor sections (140), individual sections can be lifted using the provided lift points to access the sub-floor space (146) if needed. The wall sections (120) are modular; slotted wall panels (124) can be removed from support posts (122) for replacement. Besides, the sub-floor space 8146) is sufficient to allow external flushing from the lateral ends of the bed.

[0059] ON‑SITE CONSTRUCTION METHOD

[0060] A representative on‑site construction method includes: (i) grading the subgrade (110) and placing the impermeable layer (112); (ii‑a) for the lateral-drain embodiment, installing lateral drainage channels (130) with removable covers and clean‑out ports; or (ii‑b) for the central-drain embodiment, installing centrally located drain inlet pipelines beneath the bed, including primary and secondary pipelines at each central drain region; (iii) anchoring support posts (122) and mounting slotted wall panels (124) to form the wall sections (120); (iv) placing the floor sections (140) to define the sub-floor aeration and discharge space (146), optionally using shims to establish the outward or inward drainage gradient; (v) placing the permeable separator layer (150) above the floor sections (140); and (vi) forming the service path between the opposing wall sections (120).

[0061] MODULARITY AND REDEPLOYMENT

[0062] The wall sections (120) and floor sections (140) are modular and reusable. Components installed at a first site can be removed and re‑installed at a second site. Interlocking edges, standardized fasteners, and lift points support rapid assembly and disassembly. The bed can be provided as standardized modules, each module including at least one wall section and optionally at least one floor section, allowing scalable assembly and resizing to match hydraulic loading and site constraints.

[0063] RECONFIGURABILITY

[0064] The architecture allows conversion between lateral-drain and central-drain configurations by exchanging drainage components (e.g., channels vs. central drain structures) and re‑orienting the floor gradient, while retaining the wall and floor modules and preserving exterior / underside maintenance access.

[0065] SYSTEM INTEGRATION

[0066] A distribution header delivers influent onto the filtration medium contained within the bed (100). In lateral-drain installations, an effluent collection manifold connects to the lateral drainage channels (130). In central-drain installations, the manifold connects to the drain inlet pipelines beneath the bed, which may discharge to an underground collector (180) disposed between beds for conveyance to downstream treatment or discharge. Flow control and sampling points may be provided as needed.

[0067] KIT

[0068] A kit for constructing a vermifiltration bed includes a plurality of wall sections (120), a plurality of floor sections (140), and drainage components selected from (i) lateral drainage channel assemblies (130) with removable covers and clean‑out ports, or (ii) centrally located drain inlet pipelines, together with fasteners and instructions for on‑site assembly.

[0069] MATERIALS AND MANUFACTURING

[0070] Wall sections (120) can be fabricated from stainless steel, coated steel, aluminum, or polymeric composites. Floor sections (140) can be polymer pallet‑type units or equivalent structural modules. Materials can be selected for pathogen resistance, optionally including antimicrobial coatings or inherently resistant polymers / metals suitable for wastewater environments. Fasteners and seals are selected for corrosion resistance and compatibility with wastewater environments. Example, non‑limiting ranges include: slot width selected to retain the chosen medium; sub-floor space height on the order of 50–250 mm; drainage slope on the order of 0.5%–2% (or higher locally where needed for the central-drain transition); and lateral drainage channel widths on the order of 150–600 mm for lateral-drain embodiments. Dimensions can be adapted to site requirements while preserving the functional relationships described herein. The design minimizes overall concrete usage by employing modular polymer floor sections and metal wall structures, reserving concrete primarily for drainage channels and service paths; in some embodiments, the support posts are made of concrete.

[0071] LIST OF REFERENCE NUMERALS100 vermifiltration bed110 subgrade112 impermeable layer120 wall section122 support post124 slotted wall panel125 welded plates126 continuous wall panel130 lateral drainage channel140 floor section142 slotted upper deck144 columnar lower portion146 Sub floor aeration and discharge space150 permeable separator layer160 primary drain inlet162 secondary drain inlet170 primary drain inlet pipeline172 secondary drain inlet pipeline180 underground collector182 collector overflow pipeline

Claims

A vermifiltration bed, comprising:a floor including an impermeable layer;a plurality of pallet type floor sections disposed above the impermeable layer, the floor sections collectively defining a sub floor aeration and discharge space;opposing wall sections along lateral sides of the vermifiltration bed, each wall section comprising a support post and a wall panel fixed to the support post, the wall panel being configured to contain a filtration medium; anda drainage arrangement in fluid communication with the sub floor aeration and discharge space and configured to evacuate treated effluent by gravity while permitting cleaning without disturbing the filtration medium.The vermifiltration bed of claim 1, wherein each floor section comprises a slotted upper deck and a columnar lower portion that spaces the slotted upper deck above the impermeable layer to define the sub floor aeration and discharge space.The vermifiltration bed of claim 2, wherein the slotted upper deck comprises a lattice of crossing ribs defining rectangular openings, and the columnar lower portion comprises a lattice of hollow standoff columns.The vermifiltration bed of claim 2, further comprising a permeable separator layer disposed above the slotted upper deck and configured to permit liquid flow while retaining the filtration medium.The vermifiltration bed of claim 1, wherein vent openings provide gaseous communication between the sub floor aeration and discharge space and ambient air.The vermifiltration bed of claim 1, wherein the floor sections are arranged to provide a drainage gradient oriented outward toward lateral sides or inward toward a bed centerline.The vermifiltration bed of claim 1, wherein the wall panel is a slotted wall panel comprising parallel elongate members arranged to define inter member slots.The vermifiltration bed of claim 7, wherein the slotted wall panel forms a wedge wire type panel and includes a lower inwardly canted baffle portion and a lower sealing strip configured to interface with the floor to inhibit bypass leakage.The vermifiltration bed of claim 1, wherein the wall panel is a continuous wall panel without through slots.The vermifiltration bed of claim 1, wherein each support post is anchored to a footing and the wall panel is removably fastened to the support post to enable replacement without disturbing the footing.The vermifiltration bed of claim 1, wherein the drainage arrangement comprises lateral drainage channels disposed along outer sides of the wall sections, the sub floor aeration and discharge space communicating with each lateral drainage channel through side openings formed at interfaces between the floor sections and the wall sections.The vermifiltration bed of claim 11, wherein the lateral drainage channels comprise exposed gutters having removable covers and clean out ports accessible from outside the vermifiltration bed.The vermifiltration bed of claim 11, wherein each lateral drainage channel is integrated with a curb that supports the support posts of the corresponding wall section.The vermifiltration bed of claim 11, further comprising an effluent collection manifold hydraulically connected to the lateral drainage channels.The vermifiltration bed of claim 1, wherein the drainage arrangement comprises centrally located drain structures disposed beneath one or more central drain regions of the vermifiltration bed and hydraulically connected to the sub floor aeration and discharge space.The vermifiltration bed of claim 15, wherein the centrally located drain structures comprise a primary drain inlet pipeline and a secondary drain inlet pipeline positioned above the primary to provide redundancy in the event of blockage.The vermifiltration bed of claim 15, wherein the centrally located drain structures comprise an open central channel with a protective grate located along a centerline of the vermifiltration bed.The vermifiltration bed of claim 15, wherein multiple central drain regions are distributed along a length of the vermifiltration bed.The vermifiltration bed of claim 15, further comprising an underground collector disposed between beds and hydraulically connected to the centrally located drain structures to convey treated effluent downstream.The vermifiltration bed of claim 1, further comprising a service path extending longitudinally between the opposing wall sections and dimensioned to permit entry and operation of maintenance equipment.The vermifiltration bed of claim 1, wherein the wall sections and floor sections are modular and reusable, being configured for removal from a first installation site and re installation at a second installation site.The vermifiltration bed of claim 1, wherein the floor sections are polymer pallet type units having interlocking edges and lift points to enable installation, removal, and reuse.The vermifiltration bed of claim 1, wherein the impermeable layer comprises a geomembrane liner over a compacted clay sub layer.The vermifiltration bed of claim 4, wherein the pallet geometry and the permeable separator layer cooperate to form aeration channels that enhance oxygen transfer into lower regions of the filtration medium.The vermifiltration bed of claim 1, wherein the architecture is reconfigurable such that a bed installed in a lateral drain configuration is convertible to a central drain configuration, or vice versa, by exchanging drainage components and re orienting the floor gradient while retaining the wall and floor sections.The vermifiltration bed of claim 1, wherein the sub floor aeration and discharge space communicates with the drainage arrangement through openings defined by interfaces between the floor sections and adjacent structures.A method of constructing a vermifiltration bed on site, the method comprising:laying an impermeable layer to form a floor;installing a drainage arrangement in fluid communication with a sub floor aeration and discharge space to be formed above the impermeable layer, the drainage arrangement comprising lateral drainage channels disposed along outer sides of wall locations or centrally located drain structures disposed beneath one or more central drain regions;anchoring support posts and mounting wall panels to the support posts to form opposing wall sections configured to contain a filtration medium;placing pallet type floor sections above the impermeable layer so as to define the sub floor aeration and discharge space in fluid communication with the drainage arrangement; andplacing a permeable separator layer above the floor sections.The method of claim 27, further comprising forming a service path extending between the opposing wall sections and dimensioned to permit operation of maintenance equipment.The method of claim 27, wherein placing the pallet type floor sections comprises installing polymer pallet type units having interlocking edges and lift points to enable removal and reuse.The method of claim 27, further comprising providing vent openings from the sub floor aeration and discharge space to ambient air.The method of claim 27, wherein installing the drainage arrangement comprises installing removable covers and clean out ports on lateral drainage channels to enable cleaning from outside the vermifiltration bed.The method of claim 27, wherein installing the drainage arrangement comprises providing inspection points for centrally located drain structures to enable flushing.The method of claim 27, further comprising using height adjustable shims beneath the pallet type floor sections to establish a drainage gradient oriented outward toward lateral sides or inward toward a bed centerline.A wall section for a vermifiltration bed, comprising:a support post configured for anchoring to a footing; anda wall panel removably fastened to the support post and configured to contain a filtration medium, the wall panel being either a continuous wall panel or a slotted wall panel.The wall section of claim 34, wherein the slotted wall panel comprises parallel elongate members arranged to form a wedge wire type panel.The wall section of claim 34, wherein the wall panel includes a lower sealing strip configured to interface with a floor of the vermifiltration bed and a lower inwardly canted baffle portion configured to inhibit migration of the filtration medium toward the wall panel.A floor section for a vermifiltration bed, comprising a slotted upper deck and a columnar lower portion configured to space the slotted upper deck above an impermeable layer to define a sub floor aeration and discharge space.The floor section of claim 37, wherein the floor section is a polymer pallet type unit having interlocking edges and lift points to enable installation, removal, and reuse.A kit for constructing a vermifiltration bed, comprising: a plurality of wall sections each comprising a support post and a wall panel configured to contain a filtration medium; a plurality of pallet type floor sections each comprising a slotted upper deck and a columnar lower portion configured to define a sub floor aeration and discharge space above an impermeable layer; drainage components selected from lateral drainage channel assemblies configured for gravity discharge and exterior access for cleaning and including removable covers and clean out ports, and centrally located drain structures selected from drain inlet pipelines and an open central channel with a protective grate; and fasteners and instructions for on site assembly.A wastewater treatment system, comprising: a distribution header configured to deliver influent onto a filtration medium contained within a vermifiltration bed according to claim 1; and an effluent collection manifold hydraulically connected to the drainage arrangement of the vermifiltration bed.

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