An environmental evaluation of food waste downstream management options: a hybrid LCA approach

Food waste treatment methods have been typically analysed using current energy generation conditions. To correctly evaluate treatment methods, they must be compared under existing and potential decarbonisation scenarios. This paper holistically quantifies the environmental impacts of three food waste downstream management options—incineration, composting, and anaerobic digestion (AD). Methods The assessment was carried out using a novel hybrid input–output-based life cycle assessment method (LCA), for 2014, and in a future decarbonised economy. The method introduces expanded system boundaries which reduced the level of incompleteness, a previous limitation of process-based LCA. Results Using the 2014 UK energy mix, composting achieved the best score for seven of 14 environmental impacts, while AD scored second best for ten. Incineration had the highest environmental burdens in six impacts. Uncertainties in the LCA data made it difficult determine best treatment option. There was significant environmental impact from capital goods, meaning current treatment facilities should be used for their full lifespan. Hybrid IO LCA’s included additional processes and reduced truncation error increasing overall captured environmental impacts of composting, AD, and incineration by 26, 10 and 26%, respectively. Sensitivity and Monte Carlo analysis evaluate the methods robustness and illustrate the uncertainty of current LCA methods. Major implication: hybrid IO-LCA approaches must become the new norm for LCA. Conclusion This study provided a deeper insight of the overall environmental performance of downstream food waste treatment options including ecological burdens associated with capital goods. Keywords Anaerobic digestion Incineration Composting Food waste Hybrid life cycle assessment Capital good

Potential use of the organic fraction of municipal solid waste in anaerobic co-digestion with wastewater in submerged anaerobic membrane technology

Food waste was characterized for its potential use as substrate for anaerobic co-digestion in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater (WW). 90% of the particles had sizes under 0.5 mm after grinding the food waste in a commercial food waste disposer. COD, nitrogen and phosphorus concentrations were 100, 2 and 20 times higher in food waste than their average concentrations in WW, but the relative flow contribution of both streams made COD the only pollutant that increased significantly when both substrates were mixed. As sulphate concentration in food waste was in the same range as WW, co-digestion of both substrates would increase the COD/SO4-S ratio and favour methanogenic activity in anaerobic treatments. The average methane potential of the food waste was 421 +/- 15 mL CH4 g(-1) VS, achieving 73% anaerobic biodegradability. The anaerobic co-digestion of food waste with WW is expected to increase methane production 2.9-fold. The settleable solids tests and the particle size distribution analyses confirmed that both treatment lines of a conventional WWTP (water and sludge lines) would be clearly impacted,by the incorporation of food waste into its influent. Anaerobic processes are therefore preferred over their aerobic counterparts due to their ability to valorise the high COD content to produce biogas (a renewable energy) instead of increasing the energetic costs associated with the aeration process for aerobic COD oxidation. (C) 2016 Elsevier Ltd. All rights reserved.This research work was possible thanks to financial support from the Generalitat Valenciana (project PROMETEO/2012/029) which is gratefully acknowledged.Moñino Amorós, P.; Jiménez Douglas, E.; Barat Baviera, R.; Aguado García, D.; Seco Torrecillas, A.; Ferrer, J. (2016). Potential use of the organic fraction of municipal solid waste in anaerobic co-digestion with wastewater in submerged anaerobic membrane technology. Waste Management. 56:158-165. https://doi.org/10.1016/j.wasman.2016.07.021S1581655

A multi-criteria sustainability assessment framework: development and application in comparing two food waste management options using a UK region as a case study

This is a post-peer-review, pre-copyedit version of an article published in Environmental Science and Pollution Research. The final authenticated version is available online at: https://doi.org/10.1007/s11356-018-2479-

Co-composting: An Opportunity to Produce Compost with Designated Tailor-Made Properties

AbstractCo-composting is a technique that allows the aerobic degradation of organic waste mixtures, primarily aiming at obtaining compost that can be used as fertiliser or soil amendment. As compared to the typical composting activity, the main difference is not merely the use of more than one feedstock to start and sustain the biodegradation process, but also the possibility of combining various kinds of waste to obtain 'tailored' products with designed properties, or to reclaim and valorise natural resources, such as degraded soils or polluted soils and sediments. Set up of appropriate co-composting protocols can be a way to optimise the management of waste produced by different sectors of agriculture and industry and also from human settlements. Different formulations can not only optimise the biodegradation process through the adjustment of nutrient ratios, but also lead to the formation of products with innovative properties. Moreover, co-composting can be a technique of choice for the reclamation of soils degraded by intensive agriculture or contaminated soils and sediments. In fact, an appropriate mix of organic waste and soils can restore the soil structure and induce fertility in nutrient-depleted soils, and also remediate polluted soils and sediments through degradation of organic pollutants and stabilisation of heavy metals. While the selection of different mixes of organic waste may lead to the design of composts with specific properties and the potential valorisation of selected waste materials, there are still several factors that hamper the development of co-composting platforms, mainly insufficient knowledge of some chemical and microbiological processes, but also some legislative aspects. This chapter illustrates the progress achieved in co-composting technology worldwide, some key legislative aspects related to the co-composting process, the main scientific and technical aspects that deserve research attention to further develop co-composting technology, and successful applications of co-composting for the reclamation of soils and sediments, allowing their use for cultivation or as growing media in plant nurseries. A specific case study of the production of fertile plant-growing media from sediment co-composting with green waste is also illustrated

Metrics for optimising the multi-dimensional value of resources recovered from waste in a circular economy: A critical review

© 2017 The Authors - Established assessment methods focusing on resource recovery from waste within a circular economy context consider few or even a single domain/s of value, i.e. environmental, economic, social and technical domains. This partial approach often delivers misleading messages for policy- and decision-makers. It fails to accurately represent systems complexity, and obscures impacts, trade-offs and problem shifting that resource recovery processes or systems intended to promote circular economy may cause. Here, we challenge such partial approaches by critically reviewing the existing suite of environmental, economic, social and technical metrics that have been regularly observed and used in waste management and resource recovery systems' assessment studies, upstream and downstream of the point where waste is generated. We assess the potential of those metrics to evaluate ‘complex value’ of materials, components and products, i.e., the holistic sum of their environmental, economic, social and technical benefits and impacts across the system. Findings suggest that the way resource recovery systems are assessed and evaluated require simplicity, yet must retain a suitable minimum level of detail across all domains of value, which is pivotal for enabling sound decision-making processes. Criteria for defining a suitable set of metrics for assessing resource recovery from waste require them to be simple, transparent and easy to measure, and be both system- and stakeholder-specific. Future developments must focus on providing a framework for the selection of metrics that accurately describe (or at least reliably proxy for) benefits and impacts across all domains of value, enabling effective and transparent analysis of resource recovery form waste in circular economy systems.We gratefully acknowledge support of the UK Natural Environ-ment Research Council (NERC) and the UK Economic and SocialResearch Council (ESRC) who funded this work in the context of‘Complex Value Optimisation for Resource Recovery’(CVORR)project (Grant No. NE/L014149/1)