Carbon and Water Footprints of Category 2 MBM Fertiliser
EFPRA Case Study 19
Category 2 Meat and Bone Meal (Cat 2 MBM) contains high levels of nitrogen and phosphorous, making it a suitable feedstock for fertiliser under European Animal By-products legislation. For use as fertiliser, it is blended with other organic materials to achieve the desired agronomic performance.
Fertiliser is the most sustainable use for Category 2 materials as they cannot return to the food chain directly — the alternative is to use them as a biomass fuel.
About the Report
A report by Mérieux NutriSciences | Blonk Consultants in collaboration with EFPRA analysed the carbon and water footprints of Category 2 MBM. The results show that these fertilisers could potentially offer environmental advantages compared to synthetic fertilisers with equivalent nutrient profiles.
Fertiliser with a lower carbon and water footprint can help farmers achieve net zero and other sustainability targets.
Carbon & Water Footprint
Quantified data now available for Cat 2 MBM fertiliser production
Optimum Reuse
Fertiliser is the most sustainable use for Category 2 materials
Positive Comparison
Favourable environmental profile versus synthetic fertiliser equivalents
Net Zero Support
Could help farmers reach net zero and other sustainability targets
Carbon Footprint (Global Warming Contribution)
Figure 1: Global Warming Contribution Analysis for Category 2 MBM Fertiliser
279 kg CO₂ eq. are emitted per tonne of Cat 2 MBM produced. Heat use accounts for 70% of the total climate change impact. Around 95% of heat generated is from natural gas, the remainder is from animal fat which has an insignificant contribution to climate change. Inbound logistics and electricity make up the other contributions.
279
kg CO₂ eq/tonne
Total carbon footprint of Cat 2 MBM fertiliser production
70%
Heat contribution
Natural gas & animal fat — the dominant emissions source
95%
Natural gas share
Of heat generated; animal fat remainder is near-negligible
Water Footprint (Water Use)
Figure 2: Water Use Contribution Analysis for Category 2 MBM Fertiliser
2.33 m³ of water is used per tonne of Cat 2 MBM produced. The rendering-only contribution is 1.48 m³/tonne and the rest is water used for energy production.
Water is sourced from tap, surface and ground water in various proportions at each production site. Assuming that tap water comprises 65% ground water and 35% surface water, and using the primary water use data from EFPRA members, the study found that about 85% of water use comes from ground water aquifers and 15% from surface water.
The study also used the ReCiPe LCA impact assessment method. Based on this approach, the study found that the water consumption is only 2.12 m³/tonne Category 2 MBM produced.
85%
Ground water
Share of total water use sourced from ground water aquifers
15%
Surface water
Remainder sourced from surface water
Comparison With Synthetic Fertiliser
The comparison shows that Category 2 MBM fertiliser has a 35% lower global warming impact and 17% lower water consumption impact than a macronutrient equivalent synthetic fertiliser at the point of production.
The Category 2 MBM fertiliser impacts were compared to a synthetic fertiliser, at the production point (excluding usage), based on macronutrient equivalency for nitrogen (N) and phosphorous (P) content. The MBM average content was calculated as 9.6% N and 5.2% P at 98% dry matter content. A synthetic equivalent fertiliser was derived based on commonly used conventional N and P fertilisers (mixes of ammoniacal N compounds and phosphoric acid).
Figure 3: Global Warming Contribution / tonne fertiliser production
Figure 4: Water Use / tonne fertiliser production
35% Lower Carbon Impact
Cat 2 MBM fertiliser emits 279 kg CO₂ eq/tonne versus 428 kg CO₂ eq/tonne for synthetic fertiliser — a significant reduction in global warming contribution at the point of production.
17% Lower Water Consumption
Cat 2 MBM fertiliser uses 2.33 m³/tonne versus 2.82 m³/tonne for synthetic fertiliser — a meaningful reduction in water use impact across the production process.
Limitations to Note
The most significant agricultural emissions — from fertiliser application and soil chemical interactions — are excluded from this study. The synthetic fertiliser comparison relies on secondary data from a commercial LCA database and serves only as a benchmark indication, not a full life cycle conclusion.
Methodology
Following positive results from the LCA of Category 3 rendered products (see Case Study 3), EFPRA extended the study to the carbon and water footprints of fertiliser produced from Category 2 MBM.
Scope & Allocation
The impact of Category 2 derived products is attributed to transportation from slaughterhouse to rendering facility, and rendering operations. Category 2 ABPs are "residual material" of zero value at the production point, being inappropriate for human or animal consumption. Upstream animal farming and slaughterhouse activities are excluded.
Category 2 rendering produces MBM and fat; the rendering impact was allocated to both co-products based on their ex-works prices, for both dry and wet rendering lines. The economic allocation approach shifts more weight to fat production at a share of approximately 20% MBM : 80% fat. Only the MBM fertiliser impact was reported in this study.
Data Sources
EFPRA members from France, the Netherlands, Spain, Finland and Italy provided data from seven production sites for three consecutive years of operation, 2020–2022. This included:
Mass balances of raw material inputs and product outputs
Inbound logistics from slaughterhouse to rendering
Processing energy requirements (thermal and electrical)
Water use requirements
Auxiliary material use
Wastewater treatment
For Category 2 raw material, mass balances at the slaughterhouse were based on production point prices to derive economic allocation factors. Prices for co-production of Category 2 MBM and fat were also collected.
The study followed a rigorous, primary-data-led approach across multiple European production sites, ensuring high-quality results that provide a reliable foundation for environmental benchmarking of Cat 2 MBM fertiliser.