Carbon Monoxide Formation during Aerobic Biostabilization of the Organic Fraction of Municipal Solid Waste: The Influence of Technical Parameters in a Full-Scale Treatment System

Sylwia Stegenta-Dąbrowska,Peter F Randerson,Andrzej Białowiec,Sarah R Christofides

doi:10.3390/en13215624

Sylwia Stegenta-Dąbrowska, Peter F Randerson + Show 2 more

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https://doi.org/10.3390/en13215624

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Abstract

The present study sought to investigate the formation of carbon monoxide (CO) during aerobic biostabilization (AB) of the organic fraction of municipal solid waste (OFMSW) in forced aerated piles. Understanding the factors influencing CO formation may be important not only for safety, but also for environmental and technical reasons. The objective of the study was to determine the effect of the technical parameters of the piles on the concentration of CO in the process gas during AB of the OFMSW in a full-scale waste treatment system: rate of waste aeration (from 3365 to 12,744 m3∙Mg−1), waste mass loads in the pile (from 391 to 702 Mg), thermal conditions, application of sidewalls as an element of pile bioreactor construction, concentration of O2 and CO2 in the waste piles and the duration of the process from 6 to 9 weeks. The temperature and concentration of O2, CO2, CO, CH4 were measured in each pile at weekly intervals. All six reactors provide stable thermal and aerobic conditions, but the presence of CO was observed, ranging from a few to over 2000 ppm, which demonstrated that ensuring optimum conditions for the process is not sufficient for CO to be eliminated. A moderate, non-linear rise in CO concentration was observed along with a rise in the temperature inside the reactors. Concentrations of CO were not highly correlated with those of O2 or CO2. An increase in waste mass loads increased the CO concentration in waste piles, while application of sidewalls decreased CO concentration. Increasing aeration rate had an influence on CO production, and the highest CO concentrations were noted under air flow rate 5.3 m3·Mg−1·h−1.

Highlights

Carbon monoxide (CO) emissions arising from the composting of green waste [1], organic waste [2]and the organic fraction of municipal solid waste (OFMSW) [3,4], may be a hazard in the work environment, with the risk of intoxication and even death [3]
Some researchers pursue the hypothesis that carbon monoxide is of physico-chemical and thermo-chemical origin [3,11] and that these two types of CO production pathways can co-exist in material at the same time
The composition of material used in aerobic biostabilization (AB) influences the changing properties of the waste during the process

Summary

Introduction

Carbon monoxide (CO) emissions arising from the composting of green waste [1], organic waste [2]and the organic fraction of municipal solid waste (OFMSW) [3,4], may be a hazard in the work environment, with the risk of intoxication and even death [3]. Carbon monoxide (CO) emissions arising from the composting of green waste [1], organic waste [2]. OFMSW is stabilized in mechanical and biological treatment (MBT) plants [5]. Due to the increasing number of MBT plants in Poland [6], and in Europe more generally (490 facilities [7]), research on the influence of technological parameters on CO formation during the biological stabilization of OFMSW is both important and novel. The knowledge on CO formation during waste composting or aerobic biostabilization (AB) of OFMSW is relatively poor, considering the importance of limiting workers’ exposure to CO. There are several studies attempting to explain the origin of carbon monoxide from biological processes. Haarstad et al [2] noted much larger concentrations of carbon monoxide during aerobic than in anaerobic processes, and Hellebrand and Kalk [13] linked CO release directly to the availability of oxygen

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