A manure or process wastewater lagoon takes HDPE at 60 mil, 1.5 mm in the trade tier and 1.524 mm on the exact conversion. NRCS 521 sets that floor for waste, and a clear-water pond can run half of it at 30 mil, 0.75 mm.[1]
Sheet weight and strength track the tier, from 1.41 kg/m², 22 kN/m yield and 480 N puncture at 60 mil down to 0.705 kg/m², 11 kN/m and 240 N at 30 mil.[2]
Above the floor the choice splits by surface. Textured HDPE handles the slope that has to grip, LLDPE handles the floor that keeps settling, and a lagoon using both carries 2 roll specifications on one order.[2][3]
Two things settle the surface. The slope face sets one limit and interface shear the other, and the shear side goes to a direct shear test under ASTM D5321, because no published friction angle covers the site soil.[1][4]
Thickness follows the contents
Manure and process wastewater get 60 mil under NRCS 521, clear water gets 30 mil, and the gap between them is a factor of two. Sheet weights here use the 1.5 mm and 0.75 mm trade tiers.[1]
A GCL substitute needs at least 0.75 lb/ft² of bentonite, or 3.66 kg/m², and a 1 acre floor swallows 14.8 t of it.[1][5]
GM13 lines the yield tiers up at 11 kN/m for 0.75 mm, 15 kN/m for 1.00 mm, 22 kN/m for 1.50 mm and 44 kN/m for 3.00 mm, a fourfold spread from thinnest to thickest.[2]
Any one of these 3 takes the lagoon out of the clear-water tier and locks it at 60 mil.[2]
- The lagoon holds manure, process wastewater or another liquid with solids in it
- A cover is planned for anaerobic digestion, so the sheet will meet biogas and hydrogen sulphide
- Machines will agitate, pump or desludge across the floor and the slopes
A rainwater pond with low solids and no machinery can drop to 30 mil, and the floor sheet on 1 acre drops from 5.7 t to 2.85 t, 26 percent of the 11 t a full lagoon order carries.[2]
Going from 1.50 mm to 2.00 mm adds 0.47 kg/m² of sheet. The thickness guide handles the mm and mil conversions, and the HDPE liner page lists roll widths by metric tier.
| Lagoon contents | HDPE or LLDPE | Trade tier / exact | Sheet weight |
|---|---|---|---|
| Manure and process wastewater | 60 mil | 1.5 mm / 1.524 mm | 1.41 kg/m² |
| Clear water | 30 mil | 0.75 mm / 0.762 mm | 0.705 kg/m² |
| GCL substitute, manure | 0.75 lb/ft² | 3.66 kg/m² | 14.8 t per acre |
HDPE or LLDPE
Stored waste pushes sideways at 65 lb/ft² for every foot of depth. A cover brings that down to 60 lb/ft², and once sand passes 20 percent of the solids it climbs to 72 lb/ft².[6]
Formulated HDPE runs at a density of 0.940 g/cm³ or better, carbon black between 2.0 and 3.0 percent, 500 hours of stress crack resistance, and an OIT of 100 minutes or a high-pressure OIT of 400 minutes.[2][7][8]
GRI-GM17 gives LLDPE 800 percent break elongation, enough to absorb settlement that continues after commissioning.[3]
Virgin resin is mandatory on both, with post-consumer content excluded, rework capped at 10 percent and resin density above 0.932 g/cm³.[2]
The 2,740 m² of slope runs textured HDPE and the 4,047 m² of floor runs LLDPE, joined at the transition by extrusion welding. A side-by-side comparison of HDPE and LLDPE covers that split, and the LLDPE liner page lists the roll widths and tiers.
Slopes and anchorage
Lined inner slopes stay at 2.5 horizontal to 1 vertical or flatter. The combined embankment slope should be no steeper than 5 to 1, and neither face steeper than 2 to 1, an angle of 26.6°, unless a separate stability check supports steeper faces.[1][6]
Embankment height needs 5 percent extra for settlement.[6]
A textured sheet grips through asperities that average at least 0.40 mm high. Direct shear tests put friction angles in the 30° range.[2][9]
A 1.50 mm smooth sheet breaks at 40 kN/m with 700 percent elongation. The textured version of the same sheet breaks at 16 kN/m with 100 percent elongation, and puncture drops from 480 N to 400 N.[2]
Steep faces, cover soil and machine traffic take the textured sheet. Inside 21.8° with nothing on the surface, smooth sheet is enough, with sampling for the shear test in the surface comparison.
Gas and water under the sheet
On a 1 acre floor the run from one end of an edge to the other is 63.6 m, and a 1 percent slope gives 0.64 m of fall over that distance.[1]
Organic matter in the subgrade, natural organics in the soil and a moving water table can lift the sheet off its bed.[1][10]
All pond liners with anchor trenches require venting near the top of the side slopes. Design and install venting in accordance to the manufacturer’s recommendations, with a spacing not to exceed 20 feet between vents.
Twenty feet is 6.1 m, so a 63.6 m edge takes 11 vents and the whole 254.4 m perimeter takes 42.[1]
The drain outlet ends at an inspection chamber with a valve. If a seasonal high water table or a seep shows up near the floor, a perimeter drain goes in below floor elevation, running the 63.6 m of each edge.[1]
A membrane sits over a cushion over a drainage layer, and the drainage design allows 1 hole of 0.16 in² for every acre, with the layer build under environmental containment.[1]
A second liner and leak detection
Waste storage needs a leak detection line that runs to a free outlet or an observation well. Where the subbase is gravelly, a second liner covers the floor and wraps that detection line, with permeability capped at 1×10⁻⁴ cm/s.[1]
One perforated drain is the minimum, laid at least 0.30 m below the liner, and it serves the whole 4,047 m² floor along the 90 m diagonal.[1]
Twenty anaerobic lagoons in Kansas were monitored for four years, and seepage averaged 1.1 mm/d with a peak of 2.4 mm/d. Fifteen of the 20 stayed between 0.5 and 1.5 mm/d.[11]
A rate of 1.1 mm/d puts 401.5 mm a year through the sheet, or 1,625 m³ under a 4,047 m² floor.[11]
Ammonium nitrogen reached 2,000 to 5,000 kg per hectare per year at large swine sites, against 385 kg at cattle feedlots. Doubling liner thickness cut peak groundwater ammonia nitrogen by a factor of 2.8.[11][12]
Electrical leak location to ASTM D7007 sweeps the finished sheet, for both the water-covered and the soil-covered case, with the sequence in leak location methods.[13]
Cushion and subgrade
Anything over 3/8 in, or 9.5 mm, sets off a cushion, and a sharp angular edge does the same. The cushion is either 10 oz/yd² or 339 g/m² of nonwoven geotextile, or 150 mm of soil that passes on grading and shape.[1]
PVC and GCL liners need 12 in, or 0.30 m, of cover soil. Across 7,805 m² that is 2,342 m³ of fill, and the particle ceiling is 3/8 in over membrane and 1/2 in over GCL.[1]
That cover soil goes down within 24 hours of the liner, or 98 m³ an hour.[1]
A 500 g/m² fabric carries less puncture risk over rounded gravel than over sharp crushed stone, because the edges do the damage.[14] Protection geotextile selection gets into it.
Welding and testing
Heat-wedge double fusion welding carries the main seams. Extrusion welding takes repairs, T-joints and detail work. Every double-track seam gets air pressure testing, and every extrusion seam gets a vacuum box.[1][15]
Each shift starts with 1 trial weld. Destructive samples come off the seam run for peel and shear, 1 of each.[1][16]
Agitation and pump-out points need anti-scour pads, because the surface wears fastest there. Each pad sits on a sacrificial sheet of matching weight plus 10 oz/yd² or 339 g/m² of nonwoven. Seam settings are tabulated in hot wedge and extrusion welding.[6]
Where the rules set the floor
Storage runs at 180 days minimum. Past 270 days the State Conservation Engineer has to approve, and the extra 90 days is worth 50 percent more capacity.[6]
Freeboard is 12 in, or 0.30 m, on an earthen lagoon and 6 in, or 0.15 m, on a vertical wall. Liquid storage also carries 18 in, or 0.46 m, for residual solids, unless you commit to clearing them every year.[6]
Setbacks run 300 ft (91 m) up-gradient and 200 ft (61 m) down-gradient from a well or spring, 500 ft (152 m) either way from neighbouring wells, 100 ft (30 m) from a road centreline, 100 ft (30 m) from a property line and 200 ft (61 m) from the top of bank.[6]
Fencing starts at 48 in, or 1.2 m, and 4 universal warning signs go up. Uplift head under a clay liner stays inside 0.5 ft/ft.[6]
Locate the impoundment bottom elevation a minimum of 2 feet above the seasonal high water table unless special design features are incorporated that address buoyant forces, impoundment seepage rate and non-encroachment of the water table by contaminants. Locate the impoundment bottom elevation a minimum of 2 feet above bedrock regardless of lining type.
A dairy operation reaches concentrated animal feeding operation size at 700 mature cows. Cattle hit it at 1,000 head, swine at 2,500 animals of 55 lb or more, and laying hens or broilers at 30,000 birds on a liquid manure system.[17]
Landfill design criteria put a compacted soil layer of at least 0.61 m under 1×10⁻⁷ cm/s, and the flexible membrane floor at 30 mil, or 0.762 mm, with HDPE at a 60 mil, or 1.524 mm, minimum.[18]
Chinese projects work to GB/T 17643 for polyethylene geomembrane, with the current edition on the national standards portal.[19]
| Item | Control value | Metric |
|---|---|---|
| Lined inner slope | 2.5H to 1V or flatter | 21.8° |
| Combined embankment slope (both faces) | no steeper than 5H to 1V | 11.3° |
| Single embankment face | no steeper than 2H to 1V | 26.6° |
| Settlement allowance on constructed height | an increase of at least 5 percent | n/a |
| Underliner vent spacing | no more than 20 ft | 6.1 m |
| Floor slope with underliner drainage | at least 1 percent | n/a |
| Particle size that triggers a cushion | over 3/8 in | 9.5 mm |
| Cushion grade | 10 oz/yd² nonwoven, or 6 in of soil | 339 g/m² or 150 mm |
| Soil cover on PVC and GCL liners | at least 12 in | 0.30 m |
| Placement window for cover soil | within 24 h of the liner | n/a |
| Freeboard on an earthen lagoon | at least 12 in | 0.30 m |
| Freeboard on a vertical wall | at least 6 in | 0.15 m |
| Residual solids allowance | at least 18 in | 0.46 m |
| Storage duration | 180 days minimum, 270 with approval | n/a |
| Floor elevation above the seasonal high water table | at least 2 ft | 0.61 m |
| Floor elevation above bedrock | at least 2 ft | 0.61 m |
| Secondary liner permeability ceiling | 1×10⁻⁴ cm/s | n/a |
| Perimeter fence height | at least 48 in | 1.2 m |
| Universal warning signs | at least four signs | n/a |
How much sheet you need
At 0.94 t/m³, 1.50 mm sheet runs 1.41 kg/m², and every extra 0.25 mm adds 0.235 kg/m². The standard roll is 8 m by 140 m, 1,120 m² and 1.58 t.[2]
At 2.00 mm the sheet runs 1.88 kg/m², so that 140 m roll weighs 2.11 t, or shortens to 105 m where the roll weight is held at 1.58 t.[2]
Sheet for one lagoon
The worked lagoon is a square with a 4,047 m² floor, 4 m of depth and 2.5 to 1 sides.
- 63.6 m on a side, 254.4 m around, 90 m corner to corner
- A slope face 10.77 m long, with 2,740 m² across the 4 faces
- 6,787 m² unfolded, or 7,805 m² once 15 percent goes on for overlaps, trench and offcuts
- 7 rolls of 1.50 mm sheet, 11 t in total, inside one 40HQ container
Overlaps, the anchor trench and offcuts take 15 percent of the sheet, or 1,018 m² and 0.9 of a roll. The anchor trench at a 0.9 m by 0.6 m section takes 305 m² of sheet along the 254.4 m perimeter at 1.2 m per linear metre, 30 percent of that allowance.
A 4 m deep lagoon taken out to 5 to 1 stretches the slope face from 10.77 m to 20.40 m, and the face area from 2,740 m² to 5,190 m².
That 2,449 m² difference costs 2.2 rolls. The pond liner quantity calculation adds slope, overlap, trench and waste into one total.
| Thickness | Yield | Smooth break | Smooth elongation | Textured break | Textured elongation | Smooth puncture | Textured puncture |
|---|---|---|---|---|---|---|---|
| 0.75 mm (30 mil) | 11 kN/m | 20 kN/m | 700 percent | 8 kN/m | 100 percent | 240 N | 200 N |
| 1.00 mm (40 mil) | 15 kN/m | 27 kN/m | 700 percent | 10 kN/m | 100 percent | 320 N | 267 N |
| 1.25 mm (50 mil) | 18 kN/m | 33 kN/m | 700 percent | 13 kN/m | 100 percent | 400 N | 333 N |
| 1.50 mm (60 mil) | 22 kN/m | 40 kN/m | 700 percent | 16 kN/m | 100 percent | 480 N | 400 N |
| 2.00 mm (80 mil) | 29 kN/m | 53 kN/m | 700 percent | 21 kN/m | 100 percent | 640 N | 534 N |
| 2.50 mm (100 mil) | 37 kN/m | 67 kN/m | 700 percent | 26 kN/m | 100 percent | 800 N | 667 N |
| 3.00 mm (120 mil) | 44 kN/m | 80 kN/m | 700 percent | 32 kN/m | 100 percent | 960 N | 800 N |
What to put in a quotation
A quotation needs 6 details. Miss one and the supplier has to quote the widest specification, and 3 rounds of switching between 1.50 mm and 2.00 mm push the lead time from 15 days to 25 days.
- Product type, HDPE or LLDPE
- Thickness, 60 mil or 80 mil, with 1.524 mm or 2.032 mm written next to it
- Size, either 8 m or 5.8 m wide
- Volume, in square metres or tonnes
- Destination port, since freight and container type follow from it
- Application, manure storage, a covered anaerobic lagoon or secondary containment
Trial orders start at 1 to 3 t, and export orders fill a 40HQ container. Standard items ship in 7 to 15 days, while custom sheet, mixed loads and peak season run 15 to 25 days. Widths reach 8 m and lengths get cut to the project.
An enquiry comes back as a roll table with coverage per roll, total tonnage and the container type, priced at 1.50 mm and 2.00 mm side by side. Send the 6 quotation items
Covers and liners go together
The United States had 400 operating manure-based anaerobic digestion systems in June 2024, and covered lagoons made up 174 of them, or 43.5 percent, the largest single group.[20]
In 2023 the group offset 14.8 million tonnes of CO2 equivalent and generated 3.29 million MWh. Thirty-seven systems came online that year and 73 more were under construction or being modified.[20]
AgSTAR counts more than 8,000 large dairy and hog operations as workable, or nearly 16 million MWh a year and about 2,010 MW of displaced generation.[20]
Per system, the 400 digesters produced 8,225 MWh in 2023. Biogas gathers under the sheet and lifts it, so the gas space and the vent headers get sized together with the floating cover and set out in methane barrier and floating cover design.[21][22]
How long the liner lasts
Buried or permanently submerged HDPE carries a design life of 50 to 100 years.[23] Sheet left out in ultraviolet light drops to 20 to 30 years.[24]
High-pressure OIT under GM13 has to hold 80 percent after 90 days at 85 °C, and 50 percent after 1,600 hours of ultraviolet exposure.[2]
An annual walk along the crest covers tears and punctures, separation at the inlet and outlet connections, the liquid level against the marker, and any bulging. A bulge means gas underneath, so the 11 vents along a 63.6 m edge get cleared.[1]
Trees and shrubs stay 10 ft, or 3.0 m, clear, a 763 m² band around a 1 acre lagoon. A washed anchor trench refills at 0.9 m wide by 0.3 m deep, using 68.7 m³ of soil, with the sequence for punctures and cuts in liner repair and maintenance.[1]
Moving from 1.50 mm to 2.00 mm lifts puncture from 480 N to 640 N and adds 3.7 t, or 34 percent on the 11 t order. Emptying and relining replaces the whole sheet and the anchor trench, back at the full 11 t.[2]
Both thicknesses can go on one roll table, so 1.50 mm and 2.00 mm come back with the 3.7 t uplift and the relining cost set against each other. Ask for the 1.50 mm and 2.00 mm comparison
Data basis
Superscript numbers cite NRCS Conservation Practice Standards 313 and 521, GRI test methods GM13 and GM17, ASTM D4437, D6392, D5321 and D7007, 40 CFR 258.40 and 412, the EPA AgSTAR pages, and 10 peer-reviewed papers from Geotextiles and Geomembranes, the Journal of Environmental Management and Transactions of the ASAE.
Six items carry no citation, these being the roll length and width combinations, welding parameter values, a 0.9 m by 0.6 m anchor trench, trial orders of 1 to 3 t, lead times of 7 to 15 days and 15 to 25 days, and an annual inspection. Site equipment and climate set all 6.
Every other number traces to 1 of the 20 conversions below.
- Thickness converts at 1 mil to 0.0254 mm
- Sheet weight comes from a density of 0.94 t/m³ against thickness, or 1.41 kg/m² at 1.50 mm and 0.705 kg/m² at 0.75 mm
- Length per roll comes from a constant 1.58 t roll divided by thickness, density and 8 m of width, or 140 m at 60 mil and 280 m at 30 mil, and coverage comes from 8 m by 140 m, or 1,120 m²
- Geotextile mass converts at 1 oz/yd² to 33.9 g/m², or 339 g/m² at 10 oz/yd²
- Bentonite loading converts at 1 lb/ft² to 4.882 kg/m², or 3.66 kg/m² at 0.75 lb/ft²
- Length converts at 1 ft to 0.3048 m and 1 in to 25.4 mm
- Area converts at 1 acre to 4,047 m²
- Slope angles come from the arctangent, or 21.8° at 2.5 to 1, 26.6° at 2 to 1 and 11.3° at 5 to 1. Those angles put the slope face at 10.77 m, 8.94 m or 20.40 m and the face area at 2,740 m², 2,276 m² or 5,190 m² at 4 m of depth
- Floor dimensions come from the square root of 4,047 m², or a 63.6 m side, a 254.4 m perimeter and a 90 m diagonal
- Drainage fall comes from a 1 percent gradient across the 63.6 m travel path, or 0.64 m
- Vent count comes from 63.6 m divided by 6.1 m rounded up, or 11 vents on one edge and 42 around the 254.4 m perimeter
- Total order area adds 15 percent for overlaps, anchor trench and offcuts, or 1,018 m² on top of 6,787 m², or 0.9 of a 1,120 m² roll
- Volume of cover soil comes from 7,805 m² at 0.30 m, or 2,342 m³, placed at 98 m³ an hour inside the 24 hour window
- The trench wrap comes from a 0.9 m wide by 0.6 m deep section at 1.2 m of sheet per metre, or 305 m² across 254.4 m and 30 percent of the 1,018 m² allowance
- Tier comparison multiplies sheet weight by floor area, 0.705 kg/m² over 4,047 m² coming to 2.85 t and 26 percent of the 11 t order, against 14.8 t at 3.66 kg/m²
- Refilling a washed trench takes 254.4 m by 0.9 m by 0.3 m, or 68.7 m³ of soil
- Clearance band area comes from the 254.4 m perimeter by 3.0 m, or 763 m²
- Seepage volume multiplies the measured rate by area and 365 days, or 1,625 m³ a year from 1.1 mm/d across 4,047 m²
- Output per digester comes from 3.29 million MWh divided by 400 systems, or 8,225 MWh
- The thickness uplift share comes from 3.7 t divided by 11 t, or 34 percent
Sources
- U.S. Department of Agriculture, Natural Resources Conservation Service. Conservation Practice Standard Pond Sealing or Lining, Geomembrane or Geosynthetic Clay Liner (Code 521), Vermont, April 2018 (minimum HDPE and LLDPE thickness of 60 mil for wastewater and 30 mil for clear water, gas vent spacing not to exceed 20 feet, minimum 1 percent bottom slope with underliner drainage, cushion of 10 ounce per square yard nonwoven geotextile or 6 inches of soil where particles exceed 3/8 inch, 12 inches of cover soil for PVC and GCL, hot shoe double fusion welding as the primary seaming method, leak detection line to a free outlet or observation well for waste storage, secondary liner permeability no more than 1 x 10-4 cm/sec, side slopes of 2.5H to 1V or flatter). efotg.sc.egov.usda.gov
- Geosynthetic Institute. GRI Test Method GM13: Standard Specification for Test Methods, Test Properties and Testing Frequency for High Density Polyethylene (HDPE) Smooth and Textured Geomembranes. geosynthetic-institute.org
- Geosynthetic Institute. GRI Test Method GM17: Standard Specification for Test Methods, Test Properties and Testing Frequency for Linear Low Density Polyethylene (LLDPE) Smooth and Textured Geomembranes. geosynthetic-institute.org
- ASTM International. ASTM D5321/D5321M: Standard Test Method for Determining the Shear Strength of Soil-Geosynthetic and Geosynthetic-Geosynthetic Interfaces by Direct Shear. www.astm.org
- Zhao H., Li D., Tian K. Long-term hydraulic conductivity of bentonite-polymer geosynthetic clay liners. Geotextiles and Geomembranes 52(4): 800-812, 2024. doi.org
- U.S. Department of Agriculture, Natural Resources Conservation Service. Conservation Practice Standard Waste Storage Facility (Code 313), Vermont, October 2020 (storage period minimum 180 days and 270 days with State Conservation Engineer approval, minimum 18 inches residual solids, 12 inches freeboard for earthen facilities and 6 inches for vertical-walled structures, setback distances from wells and water bodies, impoundment bottom at least 2 feet above the seasonal high water table and 2 feet above bedrock, embankment height increased by at least 5 percent for settlement, combined side slopes no steeper than 5H to 1V). efotg.sc.egov.usda.gov
- Hsuan Y.G. Data base of field incidents used to establish HDPE geomembrane stress crack resistance specifications. Geotextiles and Geomembranes 18(1): 1-22, 2000. doi.org
- Abdelaal F.B., Rowe R.K., Islam M.Z. Effect of leachate composition on the long-term performance of a HDPE geomembrane. Geotextiles and Geomembranes 42(4): 348-362, 2014. doi.org
- Chang J.Y., Feng S.J. Dynamic shear behaviors of textured geomembrane/nonwoven geotextile interface under cyclic loading. Geotextiles and Geomembranes 49(2): 388-398, 2021. doi.org
- Bouazza A., Vangpaisal T. Laboratory investigation of gas leakage rate through a GM/GCL composite liner due to a circular defect in the geomembrane. Geotextiles and Geomembranes 24(2): 110-115, 2006. doi.org
- Ham J.M. Seepage Losses from Animal Waste Lagoons: A Summary of a Four-Year Investigation in Kansas. Transactions of the ASAE 45(4): 983-992, 2002, indexed in FAO AGRIS (seepage from 20 anaerobic lagoons averaged 1.1 mm per day and ranged from 0.2 to 2.4 mm per day, 15 of 20 between 0.5 and 1.5 mm per day; average liner hydraulic conductivity 1.8 x 10-7 cm/sec; ammonium-nitrogen seepage of 2,000 to 5,000 kg per hectare per year at large swine sites against 385 kg at cattle feedlots; nutrient concentrations returning to background about 3 m below the lagoon floor). agris.fao.org
- Rudko N., Muenich R.L., Garcia M., Xu T. Development of a point-source model to improve simulations of manure lagoon interactions with the environment. Journal of Environmental Management 325(Pt A): 116332, 2023 (doubling the lagoon liner thickness attenuated peak groundwater ammonia-nitrogen concentrations by a factor of 2.8). doi.org
- ASTM International. ASTM D7007: Standard Practices for Electrical Methods for Locating Leaks in Geomembranes Covered with Water or Earth Materials. www.astm.org
- Dickinson S., Brachman R. Deformations of a geosynthetic clay liner beneath a geomembrane wrinkle and coarse gravel. Geotextiles and Geomembranes 24(5): 285-298, 2006. doi.org
- ASTM International. ASTM D4437/D4437M: Standard Practice for Nondestructive Testing (NDT) for Determining the Integrity of Seams Used in Joining Flexible Polymeric Sheet Geomembranes. www.astm.org
- ASTM International. ASTM D6392: Standard Test Method for Determining the Integrity of Nonreinforced Geomembrane Seams Produced Using Thermo-Fusion Methods. www.astm.org
- U.S. Electronic Code of Federal Regulations. Title 40, Part 412: Concentrated Animal Feeding Operations (CAFO) Point Source Category (subpart thresholds of 700 mature dairy cows, 1,000 cattle other than mature dairy cows, 2,500 swine weighing 55 pounds or more, 30,000 laying hens or broilers on a liquid manure handling system and 82,000 laying hens on other systems). www.ecfr.gov
- U.S. Electronic Code of Federal Regulations. Title 40, Section 258.40: Design criteria for municipal solid waste landfill units. www.ecfr.gov
- State Administration for Market Regulation of China. National standards full-text public system (geosynthetics standards) [in Chinese]. openstd.samr.gov.cn
- U.S. Environmental Protection Agency. AgSTAR Data and Trends (400 operating manure-based anaerobic digestion systems as of June 2024, comprising 343 dairy, 50 hog, 8 poultry and 9 beef; 174 covered lagoon systems, 43.5 percent of the total; 14.8 million metric tons of CO2 equivalent reduced in 2023; 3.29 million MWh generated; more than 8,000 large dairy and hog operations technically feasible, nearly 16 million MWh per year and about 2,010 MW of displaced generation). www.epa.gov
- U.S. Environmental Protection Agency. AgSTAR: anaerobic digestion on livestock farms. www.epa.gov
- U.S. Environmental Protection Agency. AgSTAR: How does anaerobic digestion work? (process description and benefits of anaerobic digestion on livestock farms). www.epa.gov
- Rowe R., Rimal S., Sangam H. Ageing of HDPE geomembrane exposed to air, water and leachate at different temperatures. Geotextiles and Geomembranes 27(2): 137-151, 2009. doi.org
- Tian K., Benson C.H., Yang Y., Tinjum J.M. Radiation dose and antioxidant depletion in a HDPE geomembrane. Geotextiles and Geomembranes 46(4): 426-435, 2018. doi.org
