Biofiltration of composting gases using different municipal solid waste-pruning residue composts: Monitoring by using an electronic nose

► We assayed four compost biofilter beds for treating air from kitchen waste composting. ► Biofilter composts, of different particle sizes, were made from MSW with and without pruning waste. ► VOC removal efficiencies were greater than 90% for all composts. ► An electronic nose detected qualitative differences due to compost type. ► Data sets from electronic nose can be correlated to those of photoionization detector. The concentration of volatile organic compounds (VOCs) during the composting of kitchen waste and pruning residues, and the abatement of VOCs by different compost biofilters was studied. VOCs removal efficiencies greater than 90% were obtained using composts of municipal solid waste (MSW) or MSW-pruning residue as biofilter material. An electronic nose identified qualitative differences among the biofilter output gases at very low concentrations of VOCs. These differences were related to compost constituents, compost particle size (2–7 or 7–20mm), and a combination of both factors. The total concentration of VOCs determined by a photoionization analyser and inferred from electronic nose data sets were correlated over an ample range of concentrations of VOCs, showing that these techniques could be specially adapted for the monitoring of these processes.