A study of odour intensity in a closed breeding facility equipped with a catalyst filter system for Shiba goat

Abstract

Experiments were carried out to monitor behavior of odour intensity, by means of odour sensor, in a closed breeding facility with internal dimension of 850°1550°1850 (Height) for a Shiba goat equipped with a catalyst filter system for the purpose of biological contaminant elimination for CELSS. A response value of odour sensor at 23 hours in a blank test without the filter system was 322 point and that in an elimination test with the catalyst filter system was 116 point. Author's subjective evaluation of this difference in these response values concluded that the catalyst filter system performed significant reduction of odour intensity. No correlation was observed between behavior of response values and excretion pattern of Shiba goat, and also between behavior of response values and methane production. Drastic fermentation of excreta remained in excreta separator was not observed at the end of the each test. Steep increasing of the response values was recorded during 30 minutes period after feeding in the tests. Shiba goat was particularly busy in taking bait, and a quite few excreta and lively metabolism were observed and recorded in this period. It was, hence, suggested that contaminants via expiration and body odour were rather dominant than excrete in terms of odour intensity in the tests. GC Mass analysis showed that any contaminant desorbed from the catalyst filter operated in the elimination test was not detected at 25°C, which meant no adsorption equilibrium on the catalyst filter occurred during the elimination test. A reason why the response values was kept around 100 point since 2 hours after feeding in the elimination test was due to that the odour sensor was located in downstream between Shiba goat and the catalyst filter, and detecting fresh odour coming from Shiba goat. Though chloric compounds as a typical contaminant disturbing responsibility of the odour sensor were not detected in this study, an effect of contaminants on responsibility of the odour sensor might be a subject for further research.