Landfill Lining to MWAN Requirements
MWAN's landfill guidelines set minimum liner requirements for each landfill category and require every liner to be installed, tested and documented under an approved Construction Quality Assurance (CQA) plan. As an MWAN-licensed landfill lining contractor (Licence No. 005701), we supply, install, weld and test HDPE geomembranes and geotextiles, and we hand over the test records and as-built data the project needs for its CQA certification report.
Reference: MWAN TG-WM-05 (2), Standards & Technical Guidelines for the Design, Construction and Operation of Landfills, 01 November 2024.
Licensed by the National Center for Waste Management (MWAN) — Waste Management Licence No. 005701, Landfill Lining.
Minimum geomembrane by landfill category
| Category | Landfill type | Geomembrane layer |
|---|---|---|
| 1 | Hazardous wasteمردم النفايات الخطرة | Minimum 2.5 mm HDPE, OR double liner with leak detection: 2.0 mm HDPE + geocomposite drainage layer + 2.0 mm HDPE |
| 2 | Non-hazardous wasteمردم النفايات غير الخطرة | Minimum 1.5 mm HDPE |
| 3 | Inert wasteمردم النفايات الخاملة | Geomembrane not required (depends on the liner system used) |
Final thickness follows the approved design and may be increased based on the project's risk assessment.
Protection layer (Categories 1 and 2)
A protection layer of geotextile and/or fine sand is placed over the geomembrane to protect it from sharp objects during construction and operation. The geotextile grade or sand thickness is set by analysis or testing. We supply and install the geotextile protection layer.
What the MWAN CQA plan covers for the geomembrane
In summary, the plan has to address:
- Manufacturing details and material specifications
- Supply, delivery, storage and handling
- Conformance testing to international methods (ASTM / ISO)
- Deployment of geomembrane panels
- Welding of trial seams and field seams
- Sampling and testing, non-destructive and destructive
- Repair procedures
- Protection and backfilling
The guideline also requires that:
- Liner drawings and documents are verified and approved by a qualified engineer.
- Geosynthetics are manufactured, tested and installed to the latest GRI specifications and the manufacturer's guidelines.
- CQA is supervised by a suitably qualified, independent third-party engineer throughout construction.
- A final CQA certification report is submitted, including all test results (with failed tests and the corrective actions and retests), test location drawings, as-built drawings, daily site records and non-conformance records.
How we support your CQA plan
- Material to GRI-GM13 with manufacturer certificates
- Controlled delivery, storage and handling on site
- Panel layout and deployment records
- Trial welds before production welding each day
- Fusion (automatic wedge) and extrusion welding
- Non-destructive testing: vacuum box and spark testing
- Destructive testing: peel and shear tests with on-site tensiometer
- Documented repairs with retest
- Seam, test-location and repair records for the as-built drawings and the CQA certification report
- Third-party validation on request
- Full cooperation with the project's independent CQA engineer
Leak location survey (LLS)
The MWAN guideline notes that a leak location survey after cover placement is not mandatory, but may be required by the facility owner or the authorities on high-risk sites. We coordinate LLS with specialist survey providers when the project specifies it.
Leachate ponds and leachate evaporation cells
MWAN's guidelines require all leachate collected from a waste cell to be taken to a leachate storage facility, such as a collection tank, pond or lagoon, before it is treated, and Category 1 and 2 landfills must have a leachate storage and treatment facility. The guidelines recognise leachate evaporation cells as a valid way to contain and treat leachate in Saudi Arabia, given the high evaporation rates and the remote locations of many landfills.
We supply, install, weld and test HDPE liners for leachate ponds, lagoons and evaporation cells, including the welds around pipe penetrations, with the same QA/QC records we hand over for the landfill cell.
What the guideline says about leachate
- Leachate storage units must be properly lined, or built from chemically resistant materials such as HDPE.
- All leachate collection and transfer pipes must be HDPE, because of its high chemical resistance.
- The collection network is designed for a 1-in-50-year storm, with pipes of at least 200 mm diameter, normally no more than 25 m apart.
- The leachate head on the drainage layer must not exceed 0.30 m, measured at the lowest point.
- Where leachate is drained by gravity, extra monitoring of the pipe welds where the pipe passes through the second barrier is strongly recommended.
- Leachate may not be discharged unless it meets the discharge criteria, proven by an accredited laboratory.
Request a quotation for your landfill cell
Send us the application, approximate area, liner specification and site location, and we'll come back to you with a scope and price.