A methodology to evaluate odours emitted by zootechnic breeding waste

Emissions from zootechnic breedings waste may cause great annoyance to exposed people, even though they are not associated to toxicology impact problem; it is however important to evaluate the presence of the olfactory substances in order to identify the sources and to minimize the spreading of odours. The substances contained in the biosolid waste which cause odours belong to several different chemical compounds classes: fat volatile acids, mixture of nitrogen, mixtures of organic and inorganic sulphur, aromatic mixtures, aldehydes. The high number of chemical compounds causing olfactory sensations, the very low perceptive threshold and the minimum concentration in air of most of them, make extremely difficult to evaluate the olfactory impact of a breeding through measurements. The paper presents a new technique to identify and evaluate odours from breedings waste, using a technology able to identify odours “in situ” using a peculiar dynamic sensor: the gascromatographer with mass spectrometer. Its probe is able to evaluate concentrations in real time. The research focused on the development of a methodology to identify the main compounds in zootechnic breedings; beyond the description of the methodology implemented in the Lab, the results of the first “in situ” experimental campaign are presented.