The use of composting technologies to treat food waste (FW) now represents an environmentally friendly form of waste treatment, in which organic matter can decompose biologically. However, the damaging emissions of composting technologies for FW treatment vary, thus a life cycle assessment (LCA) approach is often used to certify the quality of the decision-making process. This study quantifies and compares the environmental impact of two scenarios in Malaysia: windrow and hybrid composting (windrow integrated with a landfill) technologies.  The scenario modeling was performed via GaBi v6.0 software using 1 ton of pre-treated FW as a functional unit, with the analysis based on the ReCiPe (H) v1.07 characterization method. The midpoint results revealed that windrow composting technology has a lower environmental impact and is an environmentally friendly option compared to hybrid technology. Treating FW in a windrow scenario has relatively low power requirements for operation with the added advantageous properties of compost production, and a substantial reduction in the distances transferred by the road. The hybrid scenario had the largest negative environmental impact in all categories, such as climate change (1.45E+03 kg CO2 eq), and ozone depletion (4.39E-09kg CFC-11 eq) because of the energy-intensive waste collection and treatment activities it needs, and with no landfill gas filtration. Finally, based on the single score synthesis, windrow is considered as an appropriate treatment with the avoidance of Resource Depletion (6.61E+02 Pt).

The activities related to agri-food production and the disposal of its waste account for a large number of greenhouse gas emissions. In many cases, food waste (FW) management is established by making a single assessment for its sustainability based on economical or environmental impacts. However, social impact assessments on stakeholders are often incomplete or missing, and its efficiency is seldom measured. Decision-making in waste management strategies, such as the acquisition of appropriate waste treatment sites or methods used, frequently involves multiple stakeholders such as government, municipalities, industries, experts, or public sectors. Due to the complication of differing criteria and alternatives in FW management technology, a multi-criteria decision-making (MCDM) methodology is recommended to certify the quality of the decision-making process. This paper reviews the use of MCDM as decision supporting techniques in modelling and analysing decision making in situations with multiple stakeholders for FW management. The synthesis results obtained through the MCDM tool will be more reliable when requesting confirmation from stakeholders based on a recommended minimum range of criteria for each sustainability dimension in the FW issues. Finally, potential studies in this area have been proposed.

Anaerobic digestion (AD) is especially useful in the treatment of organic waste sources, such as food waste (FW) since AD can support the generation of clean energy while preventing the hazards of uncontrolled GHG pollution originating from landfills. However, the potential environmental impacts of dry AD and integrated wet AD treatment are largely unknown, particularly in Malaysia. Thus, this study aimed to compare the potential environmental impacts of four FW treatment technologies in Malaysia: landfill (Sc0), dry anaerobic digestion (Sc1), wet anaerobic digestion combined with windrow composting (Sc2), and wet anaerobic digestion combined with windrow composting and landfill (Sc3). The scenario modelling was performed via GaBi v6.0 software using 1 ton of pre-treated FW as a functional unit, with the analysis of environmental impact scores being based on the ReCiPe (H) v1.07 characterization method. At the midpoint assessment, the Sc1 produced extensive improvements in 12 mid-point impact categories, being the most environmentally favoured FW treatment method compared to the other options in critical categories such as global warming, depletion of fossils and agricultural land occupation. The Sc1 mesophilic conducting reactor in this study used less energy for heating, without generating waste water while requiring a small operating area. Sc3 had the lowest environmental performance since the emissions into the air from windrow composting and landfill were discharged completely without any form of treatment like capturing or flaring. Finally, through the single score analysis, Sc1 was regarded as an appropriate FW treatment technology with the least damaging impact on resource depletion, human health, and ecosystems in comparison to all scenarios. This was accomplished through relatively low power demands for the operation, shorter road transport distances, and a substantial reduction in the amount of waste and electricity generation. These analyses provide a useful framework for understanding the important characteristics of anaerobic treatment despite the divergent challenges faced by the different processes.

The integrated models specifically designed to help decision-making in food waste (FW) composting management through the analysis of previous research studies are reviewed. The integrated models are built predominantly within three decision-supporting tools, which include life-cycle assessment (LCA), life cycle costing (LCC), and multi-criteria decision-making (MCDM). Different integrated models were discussed and their strengths, limitations, and crucial problems as well as their potential integration were evaluated. Apparently, there has been no in-depth analysis of its approaches and potentialities of combining harmonically the LCA, LCC, and MCDM analysis tools in the FW composting management which taking into consideration multiple stakeholders. Thus, the combined LCA, LCC and MCDM with cluster analysis (CA) is suggested. The concepts underlying the sustainable FW composting management model can be divided into several aspects in terms of environmental friendliness, financial profitability, and social acceptance. This gives an insight and facilitates to waste management sectors to decide on a preferable FW composting management.

Wet anaerobic digestion (AD) is one of the most widely implemented systems that valorize food waste (FW) for biogas production. Despite the undeniable AD benefits, the environmental impact of AD could differ depending on the biogas systems used. This article examines the hotspots on environmental impact of FW management such as global warming and ozone depletion based on integrated wet AD by utilizing a life cycle assessment approach. The integrated wet AD scenario in this study is a technology that combines wet AD, aerobic windrow composting and a landfill. The scenario modelling was accomplished by applying GaBi v6.0 software with 1 ton of pre-treated FW as a functional unit, and the analysis was based on the ReCiPe (H) v1.07 characterization technique. At the midpoint level, it was observed that the integrated wet AD presented the most significant environmental impact in terms of ionizing radiation (1.4×100 kg U235-eq), followed by water depletion (1.11×103 m3-eq), global warming (6.27×102 kg CO2-eq), fossil depletion (2.18×102 kg oil-eq) and human toxicity (2.89×101 kg 1,4-DB-eq). The disadvantages of the integrated wet AD in global warming were associated with CO2, CH4, and N2O emissions from the energy used for process treatment and fossil fuels during transportation, primarily in landfill activities, followed by wet AD and aerobic windrow composting stages. Regarding single-score indicators, integrated wet AD presented the most resource damaging impact (3.50×103 Pt), mainly due to fossil depletion. This study emphasizes the necessity of reducing the life cycle consequences related to CH4, N2O and NH3 emissions throughout the decomposition process in integrated wet AD, particularly landfill activities.