Bionic µSoil – Organic Biofertiliser from the NRU Two-Stage Process

µSoil is not a conventional compost. It is the end product of a complete two-stage organic nitrogen refinery. Biomass and organic residues pass first through anaerobic digestion under the NRU protocol with Bionic µChar, then through a controlled aerobic composting process, to produce a standardised solid biofertiliser. The result is a CE-eligible product under the EU Fertilising Products Regulation (EU FPR) with defined NPK specification, stable soil carbon and a controlled nitrogen release profile.

The Two-Stage Process

Stage 1 – Anaerobic Digestion with Bionic µChar (NRU Protocol)

Bionic µChar is added to the biogas reactor. The high adsorption capacity and pH-buffering effect of µChar (documented in BLG GmbH process analytics and NRU White Paper v11) produce three simultaneous effects in the reactor: ammonium nitrogen is directly adsorbed onto the µChar surface and carried through the process as a slow-release carrier; pH stabilisation prevents the formation of inhibitory free ammonia and retains the large majority of total nitrogen through the digestion stage; and methane yield is increased in parallel.

The digestate leaving Stage 1 is not a fertiliser for direct field application. It is a concentrated, hygienised intermediate — the optimal feedstock for Stage 2.

Stage 2 – µSoil Composting

The nitrogen-loaded digestate is combined with co-substrates (e.g. poultry dry matter, cattle manure, straw) and a fresh µChar top-up, then composted under thermophilic conditions. The high cation exchange capacity of µChar prevents ammonia volatilisation during the hot composting phase — precisely the conditions under which unbound ammonium would otherwise escape most aggressively. Nitrogen retention through the two-stage process substantially exceeds conventional digestate or composting routes according to NRU White Paper v11 and BLG GmbH process modelling (literature comparison; project-specific field validation pending).

µSoil Product Properties

Slow-Release Nitrogen: the Agronomic Advantage

The nitrogen in µSoil is not free ammonium. It exists in two stabilised forms: char-adsorbed and humus-complexed. Both forms release nitrogen in a demand-driven profile controlled by root exudate chemistry and microbial activity — not by uncontrolled ammonia volatilisation. The release profile is qualitatively comparable to coated urea products (laboratory batches; no independent field studies) and corresponds to the release profile of EU FPR category PFC 1(C)(II) (slow-release fertiliser); formal conformity assessment is part of ongoing project development.

Why µSoil Is Superior to Liquid Digestate

Liquid digestate application loses a substantial fraction of ammoniacal nitrogen shortly after spreading through ammonia volatilisation — thermodynamically determined, not fully avoidable operationally. The concentrated nitrogen pulse also generates climate-relevant nitrous oxide emissions in the soil. µSoil eliminates these loss mechanisms at source: the stable, char-bound nitrogen leaves the process as a solid and reaches the soil in an agronomically superior form.

Regulatory Classification

µSoil is designed as a CE-eligible product under EU Fertilising Products Regulation (EU) 2019/1009. µChar qualifies as a component material under CMC 14 (pyrolysis and gasification materials). Full conformity assessment is part of ongoing project development. The stable carbon in µSoil is in principle eligible for CRCF certification; the final crediting methodology is under development.

Further Technical Documentation