Purpose Bio-based recycling systems and agricultural production using recycled materials are often evaluated separately. This study performs an environmental and socio-economic life cycle assessment (LCA) of a food waste treatment and spinach farming system in Japan. The environmental and economic tradeoffs of introducing a recycling system and the net environmental benefit of the substitution of market fertilizer considering operation changes are also examined. Methods Three scenarios were developed and compared. In the conventional (CV) scenario, food waste is collected, incinerated, and disposed of in landfill, and the farmer uses market organic fertilizer. The on-site composting (OC) scenario processes food waste using an on-site garbage disposer and transports compost to a nearby spinach farmer. Food waste in the centralized composting (CC) scenario is transported to a centralized composting facility and resultant compost is sent to the farm. Primary data were obtained from field experiments and interviews. Non-greenhouse gas (GHG) emissions from the field and nitrogen leaching to water systems were simulated using the denitrification-decomposition (DNDC) model. The environmental LCA targeted climate change, eutrophication, and waste landfill. An input-output analysis estimated socio-economic indicators, namely gross added value and employment inducement effect.
Results and discussionThe scenario with the lowest impact is the CC scenario. Climate change and eutrophication impacts are highest in the OC scenario and waste landfill impacts are most significant in the CV scenario. The weighted impact by LIME2 can be reduced by 47% in the CC scenario and 17% in the OC scenario due to the recycling of food waste instead of dumping in the landfill. The difference in socio-economic indicators between the scenarios was relatively small, although the CV scenario encouraged more employment. The substitution effect of composting, as well as the environmental impact reduction of replacing market organic fertilizer with compost, will result in 28.7% of the avoided impacts in GHG emissions. Conclusions Both composting scenarios are feasible from an environmental and socio-economic perspective when compared with conventional organic production, although there is a tradeoff between waste landfill and GHG emissions for the on-site composting system. However, the OC scenario needs to save electricity to improve its environmental competitiveness with the CV scenario. When considering the substitution effect of composting, it is recommended to take into account that agricultural operation also changes.
The shortage of labor is one of the major challenges facing agriculture in Japan. Technological innovations are required to overcome the limitations of the workload per worker. One such innovation is smart agriculture, which utilizes advanced technologies such as robots, AI, and IoT. This study aimed to provide data on the workload and pest control costs for the development of sustainable agriculture. The cost of pest control was compared between a boom sprayer, power sprayer, and unmanned aerial vehicles (UAVs) for two model rice farmers. The Ovako Working Posture Analysis System (OWAS) and metabolic equivalent (METs) were used to measure workloads while using UAVs. The labor cost was reduced to half with the usage of UAVs compared with conventional machines. The resulting METs, or physical activity during pest-control work using UAVs, could be lower than those when using pest control machines. Through OWAS, 63.86% of the total jobs using UAVs were identified as having a low risk of musculoskeletal injury. The results suggest that UAVs could compensate for the shortage of workers, and these are effective tools to support the expansion of the agricultural area.
Existing research shows that lifestyle changes and sustainable consumption play an important role in global warming mitigation. One way to alter consumer behavior and make it more environmentally responsible is to enhance communication between all stakeholders, that is, producers, retailers, and consumers. This paper evaluates the GHG reduction potential of changing daily shopping behavior through behavioral transformation. Behaviorally transformative actions in this context cover select foods and daily necessities, and are analyzed here from a life cycle assessment perspective. We developed multiple product selection scenarios to evaluate GHG emissions related to the purchase of daily commodities. Based on life cycle assessment, we estimated GHG emissions from production and distribution both in terms of current product selection and possible improved selection. Among other results, our study shows that due to seasonal consumption and energy conversion, greenhouse fruits and vegetables have high potential to reduce GHG emission. The GHG reduction potential of each individual commodity is not high because daily commodities consist of a number of goods. However, combinations of various actions can achieve a high reduction potential.
Sustainable consumption plays an important role in the mitigation of global warming and the conservation of energy. Promoting more environmentally responsible consumer behavior, especially through open communication between stakeholders, is one way to achieve low-carbon consumption. This study evaluates the potential for reducing greenhouse gas (GHG) emissions through behavioral transformation of consumers in terms of their daily shopping habits. In this context, the behavioral transformative actions pertain to certain foods and daily necessities, and are analyzed from a life cycle assessment perspective. We developed multiple product-selection scenarios to evaluate GHG emissions related to the daily purchase of commodities. Based on the life cycle assessment, we estimated the GHG emissions that result from the production and distribution of these commodities, pertaining to both the current product selection and to a possibly improved selection. The results of our study show that because of seasonal consumption patterns and energy conversion, there is a substantial potential to reduce GHG emissions resulting from outof-season produce cultivation. The GHG reduction potential is not high for each individual commodity because diverse commodities are needed on a daily basis. However, various actions in combination could have substantial potential for reducing emissions.
Environmental impact assessments for wastewater treatment plants (WWTPs) have evaluated many endpoints including emissions of greenhouse gases, discharges of nutrients and discharges of toxic substances. The primary objective of this study was the development of an integrated environmental impact assessment model for wastewater treatment processes. The assessment model was based on an impact assessment methodology used in Japan for life cycle assessments. Specifically, eutrophication was taken into account in the model along with the impacts of free ammonia, because this chemical was known to have toxic effects on aquatic ecosystems. The model developed was then applied to an actual WWTP operating under two different conditions (case 1, without nitrification; case 2, with nitrification), and the best operating conditions were evaluated based on nitrogen emissions. The results showed that the main contributor to the environmental impacts of the WWTP in case 1 was ecotoxicity from discharges of NH 4 -N. In case 2, the main contributor was eutrophication from discharges of total nitrogen. These results demonstrated that the overall environmental impacts of WWTPs should decrease when nitrification is employed because this will reduce the impacts associated with the ecotoxicity of NH 4 -N.
Synopsis: This study evaluated the lifecycle reduction potential and the payback time of CO 2 originated from general detached household electricity consumption by introducing the DC LED lighting system utilizing photovoltaic power generation and storage battery. Among various DC LED lighting systems, the system with storage battery capacity adjusted to night lighting power demand showed relatively high CO 2 reduction potential. In the system with storage battery capacity extended to whole daytime surplus power generation, shortening of battery lifetime caused by repeated complete discharge should affect lifecycle CO 2 increase of the system. The CO 2 payback time of DC LED lighting system varied between 1.5 and 2 years according as several regional characteristics such as electrical grid CO 2 emission factor, photovoltaic power condition and storage battery lifetime related to the required capacity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.