The rise in production and consumption has significantly increased urban and agro-food industry waste, posing complex environmental management challenges. Materials such as agricultural residues, garden waste, paper, domestic solid waste, and sewage sludge are often disposed of in the environment, potentially causing pollution. However, their richness in organic matter offers opportunities for agricultural soil improvement and nutrient recycling.
Determining
Total Nitrogen (TN) in sludge and biowaste like compost is thus associated with the need for nutrient and organic matter recycling, and represents a valuable element of study for soil reinforcement with organic amendment. In addition, carbon speciation is equally important for environmental characterization, and a primary distinction arises between
Total Inorganic Carbon (TIC) and
Total Organic Carbon (TOC):
- TIC, found as carbonates released as CO₂ by acid treatment, is generally harmless and common in most soils, with minimal environmental impact.
- TOC encompasses all carbon forms in organic matter, including readily microbiological degradable fractions and stable compounds like hydrocarbons.
The Importance of Total Organic Carbon (TOC) Determination in Environmental Samples
The Total Organic Carbon (TOC) can be present in large quantities in environmental samples and it represents:
- A good indicator to evaluate soil quality in agriculture.
- A pollution assessment method for ecological risk evaluation of organic contaminants.
- A classification metric for waste disposal in landfills.
TOC is determined in agreement with international regulations such as ISO 10694 or EN 15936, between the different procedures the so-called “direct method” can be applied to any kind of sample matrix, providing reliable and accurate results. In this procedure, the TIC present in the samples is previously eliminated by treating the sample with acid, then the remaining organic carbon is measured directly after dry combustion, expressed in % TOC in relation to the dry mass.
➡️ THIS APPLICATION NOTE ⬅️ illustrates the sample preparation procedure and the fast, reliable, and routine determination of TN and TOC of environmental samples with the CN 802 Elemental Analyser to cover an extremely wide carbon and nitrogen concentration range. To this purpose, the analysis is applied to various sample types, including:
- Soils,
- Sludge from sewage plants treating domestic or urban waste waters,
- Biowaste derived from biodegradable fractions of municipal waste,
- Solid waste of diverse origins.
Discover how routine TN and TOC determination with our cutting-edge analytical solutions can support environmental protection and agricultural enhancement. Contact us to learn more: our experts are here to support your laboratory's needs!
Reference methods
- EN 15936:2022 - Soil, waste, treated biowaste, and sludge - Determination of total organic carbon (TOC) by dry combustion.
- EN 16168:2012 - Sludge, treated biowaste and soil - Determination of total nitrogen using dry combustion method.
- ISO 10694:1995 - Soil quality - Determination of organic and total carbon after dry combustion (elementary analysis)
- ISO 13878:1998 - Soil quality - Determination of total nitrogen content by dry combustion (elemental analysis).