ANALYSIS OF EMISSIONS FROM LAB-SCALE COMPOSTING EQUIPMENT: DATA FOR A SUSTAINABILITY CHALLENGE

The increase of global environmental consciousness is pushing more and more towardssustainable systems for the management of cities and agricultural area. Organic waste can beconverted into good soil amendments by composting, which is therefore recognized as an ecofriendly process.Recently, CNR-ISAFOM developed a simplified static composting method easy to be carried outat farm level for olive mill waste recycling; in order to analyze and model the impacts of such amethod, a highly air-forced automated apparatus including two 35-liters bioreactors has beendesigned and developed. The system is able to analyze in real time the emissions derived fromthe respiration activity of the in situ microbiota.The air flow is managed by means of mass flow controller able to keep the oxygenconcentration in the exhausted air within a pre-fixed optimal aerobic value. An accuratemonitoring of temperature in the biomass, as well as in the inlet and outlet airflow, is carried outall along the composting trials. In addition, the apparatus records the progressive weight loss ofthe two bio-reactors while the concentrations of oxygen, carbon dioxide, ammonia andhydrogen sulfide are gathered in the exhausted air by means of separate specific detectors.The equipment is managed by custom NI LabVIEW software: parameters under control arerecorded every fifteen minutes and promptly displayed in tables, graphs and spreadsheets.The apparatus has been tested by composting olive mill waste with hygroscopic additives, suchas straw and waste wool.Monitoring at a Lab-scale the amount of emissions from composting may led to optimize thoseparameters which influence the release of greenhouse gases (GHG) emissions. This may helpcomposting companies in comply the even more restrictive rules imposed by Regulators forreducing its environmental impacts.