Elemental composition (C, H, N, S) of biowaste compost samples with controlled moisture levels

The dataset contains information on the elemental composition (carbon, hydrogen, nitrogen, sulfur) of biowaste compost samples obtained during laboratory-scale composting over a 14-day process. The C, H, N, and S contents are presented as percentages for substrate samples collected at the start of the process (day 0), after 7 days (day 7), and at the end of the process (day 14), for each reactor, in two replicates. The composted material consisted of a biowaste mixture composed of cherry tree branches, fresh grass cuttings, and model food waste prepared according to Valta et al. (2019) (doi: 10.1177/0734242X18823943), in a mass ratio of 4:1.5:1, respectively. Composting was carried out at 45°C. The study included three experimental variants differing in the initial moisture content of the biowaste: Reactors 1–4 correspond to biowaste with an initial dry matter content of 68.4% (denoted as M100 – representing the highest moisture level analyzed), Reactors 5–8 correspond to biowaste with an initial dry matter content of 78.4% (denoted as M90 – representing a moisture level 10 percentage points lower than the highest), Reactors 9–12 correspond to biowaste with an initial dry matter content of 87.4% (denoted as M80 – representing a moisture level 20 percentage points lower than the highest). During the composting process, distilled water was added every three days as follows: 10 mL to reactors 1–4, 5 mL to reactors 5–8, while reactors 9–12 were incubated without any water addition throughout the process. Sample codes follow the structure: M for Moisture level (100, 90, 80), D for Day (00, 07, 14), and R for Reactor number. For example, the sample coded M100D07R4 represents material from day 7, collected from reactor 4, operating at the highest moisture level.