DOI: 10.57755/s1b5-cm63
title: Concentrations of process gases in the headspace of bioreactors during laboratory-scale food waste composting under different temperatures, oxygenation, and organic matter content

description: <p class="">The dataset contains data on the concentrations of process gases in the headspace of bioreactors during laboratory-scale food waste 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 class="">Concentration values are provided for three different process temperatures (45, 60, and 70°C; files: &#39;Variant 45C&#39;, &#39;Variant 60C&#39;, and &#39;Variant 70C&#39;, respectively). Within each temperature variant, results are further categorized according to varying food waste (FW) to mineral material (gravelite, G) ratios: 1:0, 1:1, 1:2, and 0:1 (sheets: &#39;1;0&#39;, &#39;1;1&#39;, &#39;1;2&#39;, &#39;0;1&#39;, respectively).</p><p class="">For each temperature and FW:G ratio, process gas concentrations are presented under four aeration variants, defined by oxygen supplied at a flow rate of 1 L/min for durations of 0, 0.5, 1, and 1.5 minutes.</p><p class="">Gas concentration values are reported over a 7-day process period for each variant, with two measurements taken per day (resulting in 14 measurements per replicate). The dataset includes the exact dates and times of all measurements.</p>
description: <p><span style="font-size:12.04px">A model food waste (FW) mixture (potatoes, rice, pasta, onions, apples, bananas, tomatoes, lettuce, bread, cheese, and ham) was composted.</span></p><p><span style="font-size:12.04px">To adjust the organic matter content (OMC) within the bioreactors, the FW was mixed with a mineral bulking material, gravelite (G), at volumetric ratios of 1:0, 1:1, and 1:2 (FW:G). These mixtures corresponded to dry organic matter content values of approximately 95%, 40%, and 20%, respectively. In addition, a control variant containing gravelite only (ratio 0:1, representing 0% OMC) was also included in the study.</span></p><p><span style="font-size:12.04px">The total mass of the material placed in each bioreactor varied depending on the FW:G ratio and ranged from approximately 130 g to 170 g.</span></p><p><span style="font-size:12.04px">The composting experiment was carried out over a period of 7 days in 900 mL bioreactors equipped with forced aeration. The bioreactors were placed in thermostatic chambers (ST3, POL-EKO, Wodzisław Śląski, Poland) set to constant temperatures of 45°C, 60°C, and 70°C. Each unit was sealed with a metal cap fitted with two connectors and silicone tubing. One connector remained closed throughout the experiment, while the other was operated with a Hoffmann clamp to allow intermittent connection to a portable gas analyzer (DP-28, Nanosens, Wysogotowo, Poland).</span></p><p><span style="font-size:12.04px">Measurements of gas concentrations: </span>methane (CH₄, %), carbon dioxide (CO₂, %), oxygen (O₂, %), hydrogen sulfide (H₂S, ppm), and carbon monoxide (CO, ppm)<span style="font-size:12.04px">, were performed twice daily at 9:00 AM and 4:00 PM. Each measurement session lasted approximately 2 minutes, continuing until stable readings were obtained. Following each session, the analyzer was temporarily disconnected to allow the internal sensors to return to baseline values (CO ~0 ppm, CO₂ ~0%, O₂ ~20.2%) before subsequent use.</span></p><p><span style="font-size:12.04px">Aeration was administered once daily using an oxygen concentrator (OxyFlow-10, GESS, Poland), operating at a flow rate of 10 dm³∙min⁻¹ for 0, 0.5, 1 or 1.5 minutes.</span></p>