🌿 Waste leaching test (L/S=10)
Single-stage waste leaching test at liquid-to-solid ratio 10 L/kg. Basic test for waste classification regarding acceptability for disposal at different landfill types.
Overview
The leaching test according to PN-EN 12457-4 is a key test in waste management, used to assess the potential for pollutant release from waste under water influence. Results are compared with acceptance criteria for disposal at landfills: inert, non-hazardous, and hazardous (2015 Polish regulation).
The test involves contacting crushed waste with deionized water at L/S ratio = 10 L/kg for 24 hours on a shaker. The eluate is filtered through a 0.45 µm filter and analyzed for pH, conductivity, heavy metals, chlorides, sulfates, fluorides, DOC, TDS, and other parameters.
The method is required when obtaining landfill disposal permits, assessing waste from industrial processes (slags, ashes, sludges), and in landfill environmental impact assessment.
Method principle
The waste sample (<4 mm or <10 mm) is mixed with deionized water at L/S ratio = 10 L/kg (i.e., 100 g waste + 1000 mL water) and shaken on an end-over-end shaker (5–10 rpm) for 24 ± 0.5 h. After completion, the suspension is left to settle (15 min), then filtered through a 0.45 µm membrane filter. Chemical parameters are determined in the eluate and compared with acceptance criteria for the appropriate landfill type.
Applications
- Waste classification for landfill disposal acceptability
- Assessment of waste from combustion processes (fly ash, slags)
- Testing electroplating and industrial sludges
- Assessment of construction rubble for recycling
- Landfill monitoring
- Assessment of mining waste
Key parameters
| Parameter | Value |
|---|---|
| L/S ratio | 10 L/kg (±2%) |
| Leaching time | 24 ± 0.5 h |
| Waste particle size | <4 mm (part 4) or <10 mm |
| Temperature | 20 ± 5°C |
| Filtration | 0.45 µm (membrane) |
Standard
- Standard number
- PN-EN 12457-4:2006
- Title (PL)
- Charakteryzowanie odpadów — Wymywanie — Badanie zgodności wymywania ziarnistych materiałów odpadowych i osadów — Część 4: Jednostopniowe badanie porcjowe przy stosunku cieczy do fazy stałej 10 l/kg
- Title (EN)
- Characterisation of waste — Leaching — Compliance test for leaching of granular waste materials and sludges — Part 4: One stage batch test at a liquid to solid ratio of 10 l/kg
Step-by-step procedure
1. Sample preparation
Crush waste to <4 mm (or <10 mm) particle size. Determine moisture (drying 105°C). Weigh 90–100 g (dry mass basis).
2. Leaching
Transfer waste to 2 L PE bottle. Add deionized water at L/S = 10 ratio. Close tightly. Place on shaker.
3. Shaking
Shake for 24 ± 0.5 h at 5–10 rpm (end-over-end). Temperature 20 ± 5°C.
4. Sedimentation
Leave bottle in vertical position for 15 ± 5 min. Decant supernatant.
5. Filtration
Filter eluate through 0.45 µm filter under vacuum. Collect filtrate. Measure pH and conductivity.
6. Eluate analysis
Analyze eluate: metals (ICP-OES), chlorides (IC), sulfates, fluorides, DOC, TDS. Compare with acceptance criteria.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| End-over-end shaker | Heidolph Reax 20, GFL 3040, Edmund Bühler KS 15 | 5,000–15,000 PLN |
| PE bottles 2 L | HDPE bottles with cap, for shaking | 10–30 PLN/pc. |
| Vacuum filtration system | Merck Millipore, 0.45 µm cellulose filters | 2,000–5,000 PLN |
| Laboratory balance (1 g) | Radwag WLC 6/A2, Kern PCB 6000 | 1,000–3,000 PLN |
| Grinder or crusher | Retsch SM 300, IKA MF 10 basic (to <4 mm) | 10,000–30,000 PLN |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Deionized water | — | Conductivity <0.5 mS/m, for leaching |
| Nitric acid HNO₃ 65% | 7697-37-2 | For eluate sample acidification (metal analysis) |
| Membrane filters 0.45 µm | — | Cellulose or PVDF, ø 47 mm |
Health and safety (OHS)
- Waste may contain hazardous substances — gloves, goggles, apron
- Dust from waste crushing — FFP2 dust mask
- HNO₃ — corrosive, use in fume hood
- Eluates from hazardous waste — collect as laboratory waste