The Effectiveness of Gas Recovery Systems for Managing Odour from Conventional Effluent Treatment Ponds in Palm Oil Mills in Malaysia

Gas recovery systems at palm oil mills enable the curtailment of uncontrolled greenhouse gas emissions from open anaerobic pond, but can also reduce odour, an aspect which has not yet been substantiated. The objective of this study is to evaluate the odour emission from palm oil mill effluent and the effectiveness of covers and tank digester in reducing odour emission from the open lagoons. Odour samples were obtained from the cooling ponds in conjunction with in-field odour assessment performed on site. Results demonstrated that odour released from open ponding or covered lagoon were almost comparable, ranging from 33,150 – 162,000 OU/m³, and 68,705 – 102,000 OU/m³, respectively. In contrast, odour emission from cooling pond which used tank digester system seemed markedly lower, ranging between 13,000 – 76,000 OU/m³. In fact, the analysis of ambient air close to anaerobic tank digesters proved a reduction of odour emission to the surroundings (with 3.5 OU/m³, weak intensity) compared to open pond (with 2700 OU/m³, strong intensity) or covered lagoon (with 111 OU/m³, distinct intensity). In conclusion, gas recovery systems at palm oil mills should be promoted not only towards the management of greenhouse gaseous, but also as an odour impact management strategy.