Frequently Asked Questions

EFI USA is the national leader in geosynthetic liner installation and environmental containment. We operate 5 core service lines: biogas and anaerobic digesters, geosynthetic liners, floating covers, O2 injection and H2S removal, and baffle curtains. We also serve mining containment and wastewater applications. From engineering design through installation, commissioning, and ongoing maintenance, EFI provides fully turnkey solutions.

EFI operates nationwide from three regional hubs in South Carolina (headquarters), Texas (Southern and Central US), and California (West Coast, Central Valley dairy focus). We have completed more than 4,000 projects since 1994 across 45 states plus Puerto Rico and the U.S. Virgin Islands, and internationally, with the ability to mobilize crews to any project site in the continental United States.

EFI was founded in 1993 by Dennis Shanklin in Gaston, South Carolina as Environmental Fabrics Inc. Over 30+ years of continuous operation, the company has grown from a regional geosynthetic liner installer to the national market leader with 500+ covered lagoon digester systems installed and an estimated 82% share of the US covered lagoon market.

EFI is an installation contractor with in-house engineering and fabrication. We do not manufacture geomembrane resin or sheet; we select the right material for each project from the major manufacturers, fabricate custom panels and fittings at our South Carolina facility, and install with our own crews. That independence means the material recommendation is driven by your site conditions, not by what one factory produces.

EFI serves municipal wastewater utilities, dairies, swine and poultry operations, food and beverage processors, landfills, mining operations, and industrial facilities. The common thread is engineered containment: lagoons, ponds, basins, and tanks that need to be lined, covered, or converted to capture biogas. Industry-specific pages on this site cover dairy, swine, poultry, food processing, landfill, and municipal applications in detail.

Yes, constantly. Many of our projects arrive through civil and environmental engineering firms that specify the containment system and bring EFI in for design support, constructability review, and installation. We provide specification sections, material data, and QA/QC documentation that drop directly into bid packages. If you are an engineer scoping a lagoon liner or cover project, our engineering team will support your design at no cost.

A lagoon liner is an engineered geomembrane barrier installed across the bottom and side slopes of a wastewater or storage lagoon to stop liquid from seeping into the soil and groundwater. Modern liners are welded from panels of HDPE, LLDPE, RPE, or similar geosynthetics into a single continuous barrier, with every seam tested. Liners are the difference between a lagoon that contains and a lagoon that leaks.

Three situations drive most liner projects: a new lagoon that must meet permit requirements for seepage control, an existing unlined or clay-lined lagoon that no longer meets tightening groundwater regulations, and an existing geomembrane that has reached the end of its service life or failed. If your lagoon is losing level faster than evaporation explains, or your permit renewal now references seepage limits, it is time to evaluate a liner.

EFI lines municipal wastewater lagoons, industrial process water lagoons, agricultural waste lagoons for dairy, swine, and poultry operations, anaerobic and facultative treatment lagoons, sludge lagoons, equalization basins, storage lagoons, and emergency containment basins. Across more than 4,000 projects since 1994, our crews have worked in essentially every lagoon configuration used in the United States.

The workhorse materials are HDPE for chemical resistance and strength, LLDPE for flexibility on settlement-prone subgrades, RPE and RPP for reinforced applications, PVC for complex geometry, XR-5 for aggressive chemical service, and geosynthetic clay liners where a composite system is specified. EFI installs all of them, and our engineers match the material to the waste stream, subgrade, and exposure conditions rather than defaulting to one product.

Most wastewater lagoon liners are 40 to 60 mil geomembrane, with 60 mil HDPE the most common specification for municipal and industrial service. Thicker is not automatically better: the right thickness balances puncture resistance, weldability, flexibility over the subgrade, and cost. Exposed liners and liners under mechanical loading justify heavier gauge. EFI's engineers recommend thickness as part of the material selection for every project.

A properly installed geosynthetic liner typically lasts 20+ years, and covered or submerged liners routinely outlast exposed ones because UV exposure is the main aging driver. Lifespan depends on material type, UV and chemical exposure, and maintenance practices. Semi-annual inspections catch small problems while they are still patches instead of replacements, which is the cheapest way to extend service life.

Cost is driven by five factors: lagoon size, material and thickness, subgrade condition, whether the lagoon must stay in service during the work, and mobilization distance. A small agricultural lagoon and a multi-acre municipal reline are very different projects, so honest pricing requires a site assessment. EFI provides free assessments and detailed proposals with project-specific pricing, and because we self-perform the installation there is no markup stack from layered subcontractors.

Installation follows a fixed sequence: dewater and clean the lagoon, prepare and proof-roll the subgrade, deploy geotextile underlayment where specified, deploy geomembrane panels, wedge-weld the seams, test every seam, then complete penetrations, anchor trenches, and ballast. The subgrade work is where projects succeed or fail; a liner is only as good as what it rests on. EFI self-performs every step with our own certified crews.

Often, yes. An overlay avoids the cost and disposal burden of tearing out the old geomembrane, and the existing liner can serve as a cushion layer under the new one. Whether overlay or removal is right depends on the old liner's condition, trapped gas and water beneath it, and permit requirements. EFI evaluates both paths during the site assessment and prices the one that actually serves the project.

The common signs are unexplained level loss, wet spots or unusually green vegetation on the outside slopes, bubbles or whales (trapped gas lifting the liner), visible cracking or brittleness in exposed material, and seam separation. Any one of these justifies an inspection. Regulators tend to find leaks on their schedule, not yours, and a planned rehabilitation is always cheaper than an emergency response to a notice of violation.

Yes, when the damage is localized and the surrounding material still has service life. Punctures, tears, and failed seams are repaired with extrusion-welded patches that are tested like original seams. Repair stops making sense when the membrane itself has aged out: widespread brittleness, oxidation, or stress cracking means patches will keep chasing new failures. EFI's inspection reports state plainly which side of that line your liner is on.

Sometimes. Municipal plants often cannot take a lagoon offline, so relines are staged: the lagoon is drawn down in phases, or flow is temporarily routed to adjacent cells while each section is lined. Where full dewatering is impossible, floating and staged techniques can keep treatment running. It adds sequencing complexity but is routine work for our crews; tell us your operating constraints and the plan is built around them.

Every field seam gets nondestructive testing, air pressure for double-wedge welds or vacuum box for extrusion welds, across its full length. On top of that, EFI performs destructive seam testing every 150 linear feet, exceeding industry standards, with coupons tested for peel and shear strength in our in-house QA laboratory at our Gaston, SC headquarters. The result is a documented QA record for every foot of seam on the project.

Electrical leak location (geoelectric) testing finds pinhole and puncture leaks that visual inspection and seam testing cannot, by driving a voltage across the liner and detecting current passing through breaches. It is run after installation, and increasingly specified on municipal and industrial projects as final acceptance testing. It is the closest thing the industry has to proof that a completed liner actually holds.

A lagoon cover is an engineered geomembrane system floated on or spanning a lagoon's surface to control what crosses it: odor and emissions going up, rainwater and debris coming down, or biogas being collected. Covers are complete systems, not just membrane: ballast, anchoring, rainwater management, and, on gas-tight covers, gas collection piping are all part of the design. EFI has installed 500+ covers across the United States.

Four reasons drive most cover projects: odor control for neighbors and regulators, biogas capture for energy value or methane compliance, algae prevention by blocking sunlight, and evaporation reduction to preserve water. Many projects stack several benefits at once; a gas-tight cover that captures methane also eliminates most odor. The right cover type follows directly from which of these problems you are solving.

An impermeable cover is a gas-tight geomembrane that seals the lagoon surface completely, which is what you need for biogas capture and maximum odor control. A permeable cover blocks sunlight and suppresses odor while letting rainwater pass through into the lagoon, which eliminates the rainwater management system entirely. Permeable covers suit odor and algae control on lagoons where gas capture is not the goal; impermeable covers are required wherever methane is being collected.

Odor compounds like hydrogen sulfide are generated in the liquid and escape at the surface. A cover physically interrupts that release. An impermeable cover contains the gas entirely so it can be collected and flared or treated. A permeable cover suppresses surface emission and blocks the sunlight that drives algae cycles. Facilities under odor complaints or nuisance actions typically see the difference within days of cover completion.

Yes. A gas-tight impermeable cover turns an anaerobic lagoon into a covered lagoon digester: biogas accumulates under the membrane, is drawn off through collection piping, and is then flared for methane destruction or conditioned for beneficial use. This is EFI's core specialty, with 500+ covered lagoon digester systems installed nationwide. If your lagoon is already anaerobic, it is already making methane; the cover is what turns that liability into a controlled asset.

The membrane is sealed into an anchor trench around the full perimeter, making the lagoon surface a closed gas space. Biogas collects under the cover and is routed through collection piping to a flare or gas conditioning system. Condensate management drains the moisture that condenses under the membrane, and ballast keeps the cover geometry stable as gas volume changes. Designed as a system, the cover holds gas-tight integrity for decades.

Impermeable floating covers are designed with weighted ballast lines that shape the membrane into defined low areas, where rainwater collects and is pumped off. The rainwater management system is part of the engineered design, sized for local storm data. Permeable covers sidestep the problem entirely by letting rain pass through into the lagoon. Rainwater design is one of the clearest differences between an engineered cover and a tarp.

Covers are secured in a perimeter anchor trench and held in position by ballast pipes or weights arranged across the surface. Wind uplift is a real design load: an unballasted membrane on open water is a sail. EFI's cover designs account for site wind exposure, gas volume changes under gas-tight covers, and liquid level swings, so the cover stays in position through the weather the site actually sees. Our published cover specifications detail ballast and anchoring design.

Cover service life is typically 20+ years for properly designed and installed systems, depending on material selection, UV exposure, and gas or chemical service. Covers work harder than liners: they face sun, weather, and constant movement. Material selection matters accordingly, which is why reinforced materials are common cover choices. Regular inspections of ballast, anchor trenches, and seams are what keep a cover at full function through its design life.

The main cost drivers are surface area, cover type (permeable versus gas-tight impermeable), material, and the supporting systems: gas collection, rainwater management, and ballast. A covered lagoon digester system on a dairy typically runs $300,000 to $1.5 million installed, while large food processing systems range from $2 million to $9 million. For qualifying operations, EFI's cap-and-flare program can deploy a cover and flare system at zero cost to the waste generator.

Yes. Floating covers are routinely deployed over operating lagoons; the membrane is assembled and floated across the surface in panels without dewatering. That is one of the structural advantages of a covered lagoon digester over tank-based systems: the lagoon you already have keeps working through construction. Site logistics, gas safety, and weather windows drive the installation sequencing, all of which our crews manage on every cover project.

Localized damage, tears, seam issues, or ballast problems are repaired in place with welded patches and hardware corrections, often without taking the system down. Full replacement becomes the right call when the membrane has aged out across its area. Because EFI services covers across our 500+ installed system base, our crews have repaired or replaced essentially every cover configuration in use, including systems originally installed by others.

A baffle curtain is a suspended geomembrane wall installed inside a lagoon or tank to direct flow, prevent short-circuiting, and increase effective treatment time. If tracer studies or performance data show water taking a shortcut from inlet to outlet, baffles are usually the cheapest capacity upgrade available, far cheaper than building new volume. EFI designs and installs baffle curtain systems as one of our five core service lines.

Yes. Floating tank covers apply the same engineering to steel and concrete tanks: odor control, emissions reduction, and gas capture on digesters and storage tanks. Tank covers deal with tighter geometry and different anchoring details than lagoon covers, but the membrane systems and QA are the same. EFI installs both, which matters for plants with a mix of lagoon and tank assets.

EFI has installed over 500 covered lagoon digester (CLD) systems across the United States, representing approximately 82% of the US covered lagoon market. This makes EFI the most experienced CLD installer in the country by a significant margin, with more real-world operational data than any competitor.

A covered lagoon digester is an anaerobic lagoon sealed with a gas-tight geomembrane cover so the methane it naturally produces is captured instead of escaping to the atmosphere. The captured biogas is flared for methane destruction or used for energy. It is the lowest-cost path to anaerobic digestion because it uses the lagoon you already have rather than building tanks, and it is the dominant digester technology for US agriculture.

Generally, dairy farms with 500+ head of cattle, swine operations with 2,000+ head, or food processing facilities with significant organic wastewater volumes are good candidates for a covered lagoon digester. However, every site is different. EFI provides free feasibility assessments to determine whether a CLD system makes sense for your specific operation.

Costs vary significantly based on the size and complexity of the project. Dairy farm CLD systems typically range from $300,000 to $1.5 million, while food processing facility systems can range from $2 million to $9 million. EFI provides free site assessments and detailed proposals with project-specific pricing. Our cap-and-flare program can also deploy systems at zero cost to qualifying waste generators.

Covered lagoon digesters (CLDs) use the existing lagoon or waste storage structure with a geomembrane cover to capture biogas. They are lower cost, simpler to operate, and work well in warmer climates. Complete stirred tank reactors (CSTRs) are heated, mixed tanks that provide more controlled digestion conditions and work better in cold climates, but cost significantly more and are more complex to operate. EFI specializes in CLDs, the dominant technology for agricultural and food processing applications in the United States.

Cap-and-flare is the simplest complete methane solution: cover the lagoon, collect the biogas, and destroy the methane in an engineered flare. There is no gas upgrading plant, no pipeline interconnect, and no offtake contract to negotiate, which is why cap-and-flare projects deploy in months instead of years. For qualifying waste generators, EFI's program installs the complete system at zero cost, funded by the environmental attribute value of the destroyed methane.

It depends on scale and appetite for complexity. RNG upgrading carries high capital cost and operating burden, and it has failed economically at many mid-size sites; flaring costs a fraction as much, deploys fast, and still eliminates the methane and its odor. Many operations flare first and preserve the option to add utilization later, since the cover and collection system are the same either way. EFI's assessment lays out both paths with real numbers for your site.

Warm, saturated biogas condenses on the underside of the cover, and that water has to be drained continuously or it collects in the gas piping and chokes flow. Condensate management, low-point drains and traps engineered into the collection layout, is part of every EFI gas-tight cover design, and it is one of the details that separates a reliable digester from one that limps. Our published specifications cover condensate system design.

For standard projects, EFI can typically mobilize within 2 to 4 weeks of contract execution, and field installation of the cover and gas system is measured in weeks, not seasons, since the lagoon itself already exists. The longer poles are usually permitting and, where applicable, utility or offtake arrangements. Cap-and-flare projects avoid most of that and are the fastest route from decision to destroyed methane.

EFI USA engineers, sizes, supplies and installs oxygen and air injection systems for biogas H2S reduction. EFI can integrate injection equipment with a covered lagoon and gas-handling scope, or assess a retrofit to an existing installation. The proposal should identify equipment supply, installation, controls integration, startup and operator handoff responsibilities.

EFI uses controlled micro-aeration for biogas desulfurization in a covered anaerobic system. Its purpose is H2S reduction while preserving anaerobic digestion. Water-column aeration is a wastewater process for meeting dissolved-oxygen and treatment objectives. EFI does not supply that aerobic treatment process.

The injection rate is an engineered project value based on sulfur loading, gas flow, oxygen source, biological conditions and downstream requirements. Oxygen supplied to the system and residual oxygen measured in the biogas are different quantities. Use the approved design and operating procedures for control limits, alarms and shutdown settings.

Hydrogen sulfide is toxic and corrosive. Biogas treatment requirements depend on the downstream equipment, permit conditions and gas-quality specification. Biological load reduction can be one stage of the treatment train; polishing and other cleanup may still be required.

Oxygen injection can reduce the H2S load reaching downstream treatment. Media polishing or other cleanup may still be needed to meet an engine, upgrader or pipeline specification. Evaluate the complete treatment train, remaining media use, power, maintenance and measured gas quality when comparing options.

It can reduce the H2S load in captured biogas from a covered anaerobic lagoon. A cover and gas collection system address the emission pathway; biological treatment addresses H2S in the collected gas. A site assessment should distinguish that source from other odor sources and define the required gas treatment and operating conditions.

The design should define gas monitoring, backflow protection, alarms, shutdown functions and interfaces with the existing plant. Establish inspection, analyzer calibration and equipment maintenance schedules from the approved operating plan and manufacturer instructions. Confirm who supplies startup support, operator training and ongoing service in the proposal.

The optimal liner material depends on your specific application. HDPE (high-density polyethylene) is the standard for chemical resistance and landfill applications. LLDPE (linear low-density polyethylene) offers superior flexibility for uneven ground and settlement-prone sites. PVC works well for complex geometry. RPP (reinforced polypropylene) is the material of choice for biogas covers. EFI's engineers evaluate site conditions, chemical exposure, UV factors, and project requirements to recommend the best material for each application.

HDPE brings the best chemical resistance and lowest cost per square foot, which makes it the default for most wastewater and industrial containment. LLDPE trades some chemical resistance for much better flexibility and elongation, which matters on soft or settlement-prone subgrades where a stiffer membrane would bridge and stress. If your subgrade is well-compacted and stable, HDPE usually wins; if differential settlement is in the design conversation, LLDPE earns its premium.

Reinforced membranes like XR-5 and RPE carry a woven scrim inside the sheet, giving high tensile and tear strength at lower thickness. They earn their cost in aggressive chemical service, in floating cover applications where the membrane works mechanically every day, and where dimensional stability under load matters. For a static, well-supported lagoon liner in normal wastewater service, unreinforced HDPE or LLDPE usually remains the economical choice.

A geomembrane outperforms compacted clay on permeability by orders of magnitude, installs faster, and is testable: every seam can be verified, which no clay liner offers. Clay depends on borrow soil quality, moisture control during placement, and never drying out or cracking. Many modern permits effectively require geomembrane or a composite of both. Where regulators accept either, the geomembrane usually wins on lifecycle cost once seepage risk is priced honestly.

For lagoons and large basins, usually yes. Concrete cracks, and every crack and joint is a leak path that is expensive to chase; a welded geomembrane is a single continuous barrier at a fraction of the installed cost for large areas. Concrete keeps the advantage where heavy mechanical loading, vehicle traffic, or cleaning equipment would abuse a membrane. Many designs combine them, with concrete in high-wear zones and geomembrane across the containment area.

A GCL is a factory-made mat of bentonite clay carried between geotextiles. When hydrated, the bentonite swells into a very low permeability layer, and it self-heals small punctures. GCLs are most often used as the secondary layer in composite systems beneath a geomembrane, where regulations require redundancy. They are rarely a standalone answer for wastewater lagoons but are a strong complement where permits call for belt-and-suspenders containment.

Gas-tight covers in biogas service face UV, constant flexing, and sour gas, which is why reinforced polypropylene (RPP) and similar reinforced membranes are the materials of choice for covered lagoon digesters. HDPE and LLDPE also serve in cover applications, and material selection follows gas composition, site weather, and design life. EFI installs all major cover materials, so the recommendation follows the duty, not a product line.

Yes, with adjusted procedures. Cold changes membrane behavior and welding parameters: panels are stiffer, expansion allowances differ, and seaming windows narrow. EFI crews weld to temperature-adjusted parameters, run trial welds to qualify each day's conditions, and sequence deployment around weather. Winter work is routine for a national installer; what matters is that the QA record proves every seam met specification at the temperature it was actually welded.

EFI is fully turnkey. A typical project follows this path: site assessment and feasibility study, engineering design and material selection, custom fabrication at our SC facility, field installation by our certified crews, system commissioning and startup, and ongoing maintenance and monitoring. We handle every phase from the initial assessment through long-term operations.

For standard projects, EFI can typically mobilize within 2 to 4 weeks from contract execution. For emergency repairs, including liner tears, cover damage, or containment failures, we can dispatch crews within 24 to 48 hours from our nearest regional hub in South Carolina, Texas, or California.

EFI maintains rigorous quality assurance protocols throughout every installation. We perform destructive seam testing every 150 linear feet, exceeding industry standards. Our in-house QA laboratory at our Gaston, SC headquarters tests materials and welds to ensure every installation meets or exceeds engineering specifications.

Ask four questions. How many projects like mine have you completed, and can you name them? Do you self-perform with your own crews and welding equipment, or broker the work? What seam testing do you perform and what QA documentation do I receive? Can you handle the full scope, liner, cover, and gas systems, or just the membrane? EFI's answers: 4,000+ projects since 1994, self-performed nationwide, destructive testing every 150 feet with full documentation, and turnkey scope.

A complete record: material certifications for every roll delivered, panel placement drawings, trial weld logs, nondestructive test results for every seam, destructive test results from our QA laboratory, and repair logs tied to locations. This is the file your engineer and your regulator will ask for, assembled as the work happens rather than reconstructed afterward. It is also what makes warranty conversations short.

Four things get a quote moving: lagoon dimensions or surface area, what the lagoon holds, whether it can be taken out of service, and your location. Drawings, permits, and water quality data sharpen the number but are not required to start. From there EFI performs a site assessment and returns a detailed proposal with project-specific pricing. Assessments are free, including for engineers scoping budgets at the study phase.

Yes. This site publishes technical specifications for HDPE and LLDPE geomembranes, anaerobic and permeable covers, cover ballast systems, gas collection, condensate management, flare systems, baffle curtains, and O2 injection, written to drop into bid packages. Our engineering team also supports specification development directly with your firm, including constructability review before the project goes out to bid.

Yes. EFI provides comprehensive maintenance and repair services including semi-annual inspections, sludge removal, cover repairs, liner rehabilitation, and 24/7 emergency response. We maintain ongoing service relationships across our 500+ installed system base, and our field crews are experienced with every major liner and cover system on the market.

Yes, routinely. Our crews repair and rehabilitate liners, covers, and gas systems regardless of who installed them; with 500+ covered lagoon systems in our own service base, there is very little in the field we have not worked on. The first step is an inspection that documents actual condition, so the repair-versus-replace decision is made on evidence rather than on the age of the system.

Semi-annually is the standard EFI recommends and provides: once ahead of summer, when UV and biological activity peak, and once ahead of winter weather. Inspections cover membrane condition, seams, anchor trenches, ballast, gas system function on covered lagoons, and level behavior that would indicate leakage. The economics are lopsided; an inspection finding costs a patch, while the same defect found by a regulator costs far more.

Call us. For emergency repairs, including liner tears, cover damage, or containment failures, EFI dispatches crews within 24 to 48 hours from the nearest regional hub in South Carolina, Texas, or California. Emergency response is a standing part of our service operation, not a favor, and the immediate goal is always the same: stabilize containment first, then engineer the permanent fix.

Yes, on two levels: the material manufacturer warrants the geomembrane itself, and EFI stands behind the installation workmanship. The honest answer about warranties in this industry is that documentation is what makes them real, which is why every EFI project closes with a complete QA record tying materials, welds, and tests to locations. A warranty claim supported by that file is a short conversation.