Analysis of digestate quality
WESSLING is your partner for assessing the quality of your digestate and verifying its compliance with legislative requirements. Manage your digestate quality with our personalised advice and experience.
The digestate is the residual product of anaerobic digestion, composed of organic matter that is not readily biodegradable, mineral matter and water. It can be used in various ways: composting, spreading, recirculation, etc. Its quality must be exemplary, especially when it is applied as a fertiliser on crops for human consumption.
Digestate quality - our services in detail
Digestate quality - our services in detail
Agronomic value
Agronomic value and mandatory digestate checks
Digestates are applied to land because they rich in the minerals and organic constituents needed to fertilise soil. But before any land application or organic soil improvement, physicochemical laboratory tests are mandatory. WESSLING will help you to test the quality of your batches and feedstocks.
An analysis of the digestate before it is applied tells you whether it will provide the necessary amount of nutrients to your crop and ensures that organic soil improvement will not affect the quality of the soil or water table.
To determine the agronomic value of the digestate and calculate the amount of fertiliser to add to the land, we analyse:
- carbon (C and TOC) and nitrogen (N and TKN) in different forms, as they are an integral part of organic matter
- mineral elements such as phosphorus (P and P2O5), potassium (K and K2O), calcium (Ca and CaO) and magnesium (Mg and MgO), which are necessary for good plant development.
To avoid any environmental pollution, we look for pollutants in the digestate such as:
- heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, Zn)
- plastics
- metals
- glass
The analysis programs generally used are often similar to those for compost since they include the primary NPK (nitrogen, phosphorus, potassium) nutrients, which are a basis for comparison between different substrates.
Digestate quality - our services in detail
Chemical and microbiological conformity
Chemical and microbiological conformity of the digestate
To apply health safety and environmental standards, the legislator imposes tests on the physicochemical, biological and microbiological parameters of the digestate.
The substances to be tested include heavy metals (metallic trace elements or MTEs) (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, Zn), which can be found in substrates from water treatment plants.
We also test for harmful organic substances such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), associated mainly with industrial activities.
Finally, the safety of the product is ensured by testing for Escherichia coli (E. coli), Enterococci and Salmonella to confirm the bacteriological quality of the digestate.
WESSLING will help you test your digestates and fertilising materials. We also offer our expertise in the characterisation of special substrates – for example, substrates from research units, pilot plants or new-generation plants.
The decree of 13 June 2017 lays the foundations for the marketing and use of digestates from anaerobic digestion as fertilisers, but it only applies to units that use exclusively agricultural products. For digestates of different origins, monitoring of the digestate quality must be adapted.
Our teams have the necessary experience to advise you on what components to monitor and, above all, to carry out the various downstream tests and analyses.
Your contact for digestate
We will be happy to support you.
- Pauline Castillazuelo
- +33 6 13 51 29 59
- pauline.castillazuelo@wessling.fr
