As the world moves toward a circular economy, understanding material purity and the true impacts of recycling and downcycling becomes increasingly important. Life Cycle Assessment (LCA) supports this transition by tracking environmental impacts across entire value chains. One of the main databases used in LCA, ecoinvent, represents industrial activities as processes with defined inputs, outputs, and impacts.

However, ecoinvent’s current process descriptions mainly focus on linkages and environmental flows, not on material composition or mass balance. Beyond carbon and water, information on material quality, composition, and conservation of elements is often missing. Studies have shown that mass and elemental balances are not always respected, raising questions about missing flows, incomplete waste coverage, and incorrect product links.

To address this, we introduce a rebalancing algorithm based on Material Flow Analysis (MFA) principles. The algorithm estimates the composition of all products and elementary flows in ecoinvent, ensuring full compliance with mass and element conservation. The method minimizes deviations from available data while respecting physical constraints such as mass balance, elemental conservation, and reasonable composition limits.

This approach not only estimates missing data but can also detect inconsistencies, disaggregate heterogeneous flows, and identify potential errors. Key challenges include scarce data, algorithm design, and the need to handle different types of activities. Once complete, the resulting database will enable detailed circular economy assessments and will be shared as open-source software for the research community.