DOI: 10.57755/v1gj-p540
title: Dataset on process gas concentrations during composting of biowaste mixtures with controlled moisture levels

description: <p>The dataset contains information on the concentrations of process gases in the headspace of bioreactors during laboratory-scale biowaste composting (individual bioreactor volume &#61; 0.9 L): methane (CH₄, %), carbon dioxide (CO₂, %), oxygen (O₂, %), hydrogen sulfide (H₂S, ppm), and carbon monoxide (CO, ppm).</p><p>The composted material consisted of a mixture of biowaste: cherry tree branches, fresh grass cuttings, and model food waste prepared based on Valta et al. (2019) (doi: 10.1177/0734242X18823943), in a mass ratio of 4:1.5:1, respectively. Composting was conducted at 45°C.</p><p>Gas concentration values were recorded over a 14-day composting period, with one measurement taken per day (resulting in 14 measurements per replicate). The dataset includes the exact dates and times of all measurements.</p><p>Concentration values are provided for three experimental variants differing in the initial moisture content of the biowaste:</p><p>Reactors 1–4 correspond to measurements for biowaste with an initial dry matter content of 68.4%,</p><p>Reactors 5–8 – biowaste with an initial dry matter content of 78.4%,</p><p>Reactors 9–12 – biowaste with an initial dry matter content of 87.4%.</p><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>
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% lower moisture content (dry matter content of 78.4%),</li><li>and a mixture with approximately 20% 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>Reactors 1–4 contained the 68.4% dry matter mixture,</li><li>Reactors 5–8 contained the 78.4% dry matter mixture,</li><li>Reactors 9–12 contained the 87.4% dry matter mixture.</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>Each bioreactor was sealed with a metal cap equipped with two connectors and silicone tubing. One connector remained closed throughout the experiment, while the other was controlled using a Hoffmann clamp to allow periodic connection to a portable gas analyzer (DP-28, Nanosens, Wysogotowo, Poland). Measurements of gas concentrations—methane (CH₄, %), carbon dioxide (CO₂, %), oxygen (O₂, %), hydrogen sulfide (H₂S, ppm), and carbon monoxide (CO, ppm)—were conducted once daily at 10:00 AM.</p>