Overview
EN ISO 11465:2025 - Sludge and solid environmental matrices - specifies standardized methods to determine dry residue, water content, and the dry matter fraction (mass basis) for sludge, treated biowaste, soil and waste. The standard supports reporting analytical results on a dry-matter basis and applies to samples containing more than 1% dry residue or more than 1% water (mass fraction). It defines two principal approaches: Method A - drying at 105 °C (dry residue) and Method B - direct Karl Fischer titration (water content), and clarifies when each method is appropriate.
Key Topics
- Scope and applicability: Solid matrices (sludge, sludge products, treated biowaste, soil, solid waste) and liquid waste where volatiles may be present. Applies to samples >1% dry residue or water.
- Method A - Drying at 105 °C: Determination of dry residue by drying to constant mass; intended for solids and samples that become solid on drying. Notes on interferences, hazards, apparatus and sample preparation are included.
- Method B - Karl Fischer titration: Direct volumetric or coulometric determination of water content for liquid wastes and samples suspected to contain volatile organics (excluding water). Procedure covers reagents, apparatus, equivalence factor determination and analysis of liquid/solid samples.
- Calculations and expression of results: Conversion of measured dry residue or water content into the dry matter fraction (mass basis); options for field-moist or dry-residue reporting are defined.
- Quality and performance: Precision, repeatability and reproducibility data (Annex A) and general requirements/recommendations (Annex B) support method validation and laboratory QA/QC.
- Safety and laboratory competence: Emphasis that tests must be performed by suitably qualified staff and that users must follow appropriate safety practices.
Applications
- Environmental and analytical laboratories reporting contaminant concentrations on a dry-matter basis.
- Wastewater treatment plants and sludge management facilities needing standardized dry matter and moisture determinations for process control, stabilization and disposal classification.
- Soil testing and remediation projects requiring dry-matter–referenced chemical analyses.
- Composting and biowaste facilities monitoring treatment progress and product specifications.
- Regulators and auditors referencing a harmonized method for compliance, permitting and waste characterization.
Who should use it: laboratory managers, environmental chemists, soil scientists, waste management professionals, regulators and certification bodies.
Related Standards
- EN 12880 and EN 15934 - content harmonized/merged where appropriate into this edition.
- EN 15002 - referenced for phase separation procedures when multiphase samples cannot be homogenized.
- ISO/TC 190/SC 3 committee outputs on soil quality and physical/chemical characterization.
Keywords: EN ISO 11465:2025, dry matter fraction, dry residue, water content, Karl Fischer titration, drying at 105 °C, sludge, biowaste, soil, waste, environmental testing.
