Odour Intensity Assessment at Different Area of a Palm Oil Mill Using Olfactometry Method

Malaysia is one of the world’s largest palm oil exporters, amounting to 39 % of world palm oil production and 44 % of world exports [1]. Palm oil mill usually engaged with odour problem that came from the wastewater treatment pond that released odourous compounds such as ammonia, volatile organic acids, and sulfides. This study was done to investigate odour nuisance from palm oil mill operations and odour emission rate at United Oil Palm (UOP) Mill, Nibong Tebal, Penang, Malaysia. Odour assessment was done on-site at four points and odour sample was taken from four anaerobic treatment ponds. Flux hood method was used and the samples were analysed by using the olfactometry method with six panels. It was found that in the UOP mill, the highest odour emission is from the anaerobic pond 2 with the average specific odour emission rate of 10.88 OUE/sm2, follow by cooling pond, acid pond and anaerobic pond 1. Besides knowing the main source of the odour, this study was run to find the intensity and offensiveness of the palm oil mill odour. A simple questionnaire was asked to the six panels about the odour intensity and odour offensiveness, and the average for both was at 5 (very strong odour) and 3 (definitely offensive odour). Higher level of offensiveness and intensity will increase the odour complaints, but by knowing those levels, it will help in deciding the limit of odour concentration that can be released and the threshold of odour that can be accepted by humans.