DOI: 10.57755/jvg6-ft34
title: Elemental composition (C, H, N, S) of biowaste compost samples with controlled moisture levels

description: <p>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.</p><p>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.</p><p>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.</p><p>The study included three experimental variants differing in the initial moisture content of the biowaste:</p><ul><li>
<p>Reactors 1–4 correspond to biowaste with an initial dry matter content of 68.4% (denoted as M100 – representing the highest moisture level analyzed),</p>
</li><li>
<p>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),</p>
</li><li>
<p>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).</p>
</li></ul><p>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.</p><p>Sample codes follow the structure: <strong>M</strong> for Moisture level (100, 90, 80), <strong>D</strong> for Day (00, 07, 14), and <strong>R</strong> for Reactor number. For example, the sample coded <strong>M100D07R4</strong> represents material from day 7, collected from reactor 4, operating at the highest moisture level.</p>
description: <p>A model food waste (FW) mixture (potatoes, rice, pasta, onions, apples, bananas, tomatoes, lettuce, bread, cheese, and ham) was prepared based on the methodology described by Valta et al. (2019) (doi: 10.1177/0734242X18823943). The composted material consisted of a biowaste mixture: cherry tree branches cut into ~10 cm pieces, fresh grass clippings, and food waste, combined in a mass ratio of 4:1.5:1, respectively, to achieve an optimal carbon-to-nitrogen (C:N) ratio for composting.</p><p>After preparing the biowaste mixture, it was divided into three groups with varying moisture content:</p><ul><li>a mixture with an initial dry matter content of 68.4%,</li><li>a mixture with approximately 10 percentage points lower moisture content (dry matter content of 78.4%),</li><li>and a mixture with approximately 20 percentage points lower moisture content (dry matter content of 87.4%).</li></ul><p>The latter two mixtures were obtained by drying the biowaste in a laboratory dryer at 105°C for 30 minutes and 75 minutes, respectively.</p><p>Reactor assignment was as follows:</p><ul><li><p>Reactors 1–4 correspond to biowaste with an initial dry matter content of 68.4% (denoted as M100 – representing the highest moisture level analyzed),</p>
</li><li>
<p>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),</p>
</li><li>
<p>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).</p></li></ul><p>During the composting process, distilled water was applied every three days: 10 mL to reactors 1–4, 5 mL to reactors 5–8, while reactors 9–12 received no additional water. The distilled water was evenly distributed over the surface of the waste in each bioreactor using a diffuser.</p><p>The composting experiment was conducted over a 14-day period using 900 mL bioreactors. The bioreactors were placed in thermostatic chambers (ST3, POL-EKO, Wodzisław Śląski, Poland) maintained at a constant temperature of 45°C. Aeration was passive and achieved by opening the bioreactors for approximately 10 minutes daily.</p><p>The elemental composition (C, H, N, S) was assessed using a Perkin Elmer 2400 Series analyzer (Waltham, MA, USA) in accordance with the PN-EN ISO 16948:2015-07 standard in two replicates for each sample. The analysis was conducted for reactors R1-R3, R5-R7, R9-11. 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).</p>