Scientific Paper describing research work done using our designs of VOC analysers and electronic noses

Evaluating the potential of an electronic nose for detecting the onset of anearobic conditions during composting

Bioprocessing of Solid Waste & Sludge

Figuerido S.A.B and Stentiford E.I. School of Civil Engineering, University of Leeds, UK.


Most bad odours in composting plants are formed under anaerobic conditions and often they could be avoided if detected early enough. In this project an electronic nose was used to evaluate the odours produced during a composting process at bench scale. The electronic nose consists of an array of electronic chemical sensors with partial specificity and an appropriate pattern recognition system capable of recognising simple or complex odours. Their advantage is their rapid response rate and simplicity of operation. Closed reactors were set up in water baths in the laboratory to enable their operating temperature to be changed. In the experiment described in this paper the temperature was kept at 40C and the waste used was the vegetable fraction of food waste. Each reactor was fitted with an aeration system which could maintain aerobic conditions inside the reactors when needed. Samples of the headspace gas were analysed and the odour was assessed during the biodegradiation process. Oxygen was measured in the headspace gas, and parameters such as the oxidation reduction potential (redox) were measured in the solid material. The reactors were initially operated aerobically and then the air was turned off. The changes in headspace gases and redox were then monitored as the conditions became anaerobic and the results compared to those of the electronic nose. The initial results from the trials indicate that the electronic nose can detect an early transition from aerobic to anaerobic conditions, but at this stage more work is needed in the laboratory. Further trials are taking place in the field.