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A life cycle assessment of anaerobic-treated palm oil mill effluent (POME) was conducted to assess the environmental performance on two integrated treatment processes: the typical hollow fiber membrane ultrafiltration module coupled with adsorption and electro-oxidation as pretreatment. The analysis was undertaken using the ReCiPe 2016 method and SimaPro v9 software was employed using a ‘cradle-to-gate’ approach. The results showed that hollow fiber membrane from the adsorption integrated membrane impacted significantly at 42% to 99% across all impact categories for both processes. Overall, the electro-oxidation integrated membrane was discovered to have a lesser environmental impact, particularly on the ozone formation (human health) (HOFP) at 0.38 kg NOx-eq in comparison to the adsorption integrated membrane at 0.66 kg NOx-eq. The total characterization factor of the endpoint category for human health is 8.61 × 10−4 DALY (adsorption integrated membrane) and 8.45 × 10−4 DALY (electro-oxidation integrated membrane). As membrane treatment is closely linked to energy consumption, the environmental impact with different sources of energy was evaluated for both processes with the impacts decreasing in the following order: Grid > Biogas > Grid/Solar. Future research should concentrate on determining the overall ‘cradle-to-grave’ environmental impact of treating POME, as well as other scenarios involving membrane treatment energy utilization using LCA. This study can help decision-makers in identifying an environmentally sustainable POME treatment and management, especially in Malaysia.

There is an increasing interest in reducing production and emissions of greenhouse gases to combat global warming. Greenhouse gases can be produced through animal production operations. One of the major sources of greenhouse gases emitted from the animal farming is dairy cattle barns. This study measured the CH4 and CO2 emissions from dairy cattle manure decomposition trapped inside the static chambers through anaerobic digestion process by bacteria and at regular intervals by focusing on animal age and manure storage method. Samples were analyzed using gas chromatography for the estimation of CH4 and CO2 emissions. Four Friesian cows were used representing two stages of cow age (3 and 10 years old) and 1 kg of fresh manure samples were collected (feces and mixture of feces with urine). It was found that CH4 and CO2 emissions produced by cattle at the age of 3 years were higher than age of 10 years. In addition, gases emitted from fresh slurry feces were higher than liquid manure for both ages (3 and 10 years). This is due to the fact that the organic matter degradation in the feces and amount of fresh slurry feces is twice the amount of fresh slurry feces used in the liquid manure, as well as the organic matter in the manure mass for the age of 3 years is higher than for the age of 10 years. The findings from this study can provide information for improving manure management practices in animal farms.

This paper provides a brief review on wastewater treatment system and the application of life cycle assessment (LCA) for assessing its environmental performance. An extensive review regarding the geographical relevance of LCA for WWTPs, and the evaluation of sustainable wastewater treatment by LCA in both developed and developing countries are also discussed. The objective of the review is to identify knowledge gap, for the improvement of the LCA application and methodology to WWTPs. A total of 35 published articles related to wastewater treatment (WWT) and LCA from international scientific journals were studied thoroughly and summarised from 2006 to 2022. This review found that there is lack of studies concerning LCA of WWTPs that consider specific local criteria especially in the developing countries. Thus, it is important to: (1) assess the influence of seasonality (i.e., dry and wet seasons) on the environmental impact of WWT, (2) investigate environmental impacts from WWTPs in developing countries focusing on the site-specific inventory data, and (3) evaluate environmental sustainability of different processes for upgrading the wastewater treatment system. The environmental impact and cost assessment aspects are crucial for the sustainable development of WWTP. Therefore, environmental impacts must be thoroughly assessed to provide recommendation for future policy and for the water industry in determining environmental trade-offs toward sustainable development.

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