Regional circular economy implications of composting seasonal municipal biowaste for resource recovery and peat replacement

Separately collected municipal biowaste is central to regional circular economy implementation under the revised Waste Framework Directive, yet system design and planning are still often based on annual averages that obscure month-resolved constraints and opportunities. This study developed a month-resolved workflow that integrates daily inflow records with repeated reception sampling, manual fraction sorting and laboratory characterisation over one full year at a regional treatment hub in North Rhine-Westphalia, Germany, and translates these data into operational and market-relevant indicators for composting systems. Daily inflow included non-operating days and reached 352 t wet d ^− 1 , while monthly inflow ranged from 3,007 to 5,648 t wet. Composition varied strongly, with food waste ranging from 1.45 to 34.84% and garden-related fractions from 2.30 to 94.02%, while non-organic material ranged from 0 to 32.03%, indicating episodic contamination events. On a total solids basis, carbon ranged from 31.79 to 42.11% and nitrogen from 1.38 to 1.83%, with an annual mean carbon to nitrogen ratio of 22.6. Scenario translations expressed monthly outputs as humus carbon potential and as market-facing volumes, with growing media support of 5,269 to 10,686 m ³ month ^− 1 and peat displacement of 2,160 to 4,381 m³ month ^− 1 , supporting coordinated regional planning across collection design, facility capacity and market linkages. By translating biowaste variability into market-relevant volumes and substitution potentials, the study supports economic decision making for regional value chains, including compost utilisation in growing media and partial replacement of fossil peat.