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In the light of a circular economy, the Nijhuis Ammonia Recovery system (AECO-NAR) was developed to not only remove nitrogen from wastewater streams, but also produce ammonium sulfate (AS), used as fertilizer, in a single plant. The goal of this paper was to quantify the environmental impacts of side stream ammonia recovery with the AECO-NAR system and compares them with the impacts of side stream nitrogen removal combined SHARON (partly nitrification)-anammox plant. For this, an environmental life cycle assessment was performed with a functional unit (FU) of the treatment of 1 kg of total dissolved nitrogen inflow. Since AS obtained by the AECO-NAR is a by-product of the ammonia removal process, allocation was based on system expansion. Foreground inventory data were obtained from a full-scale plant. ReCiPe2016 was used to determine human health and biodiversity impacts. Results show that due to the production of AS in an integrated water treatment and production system, the AECO-NAR avoids impacts of current AS production, leading to negative impact scores. Impacts per FU decrease with increasing inflow concentrations of ammonia. Main improvement options are the use of renewable energy and the replacement of the cleaning chemical citric acid with a sustainable alternative. Total impacts of the AECO-NAR system diminish when comparing the system to the biological SHARON-Anammox system, due to production of AS fertilizer product. Due to the fertilizer production step being integrated in the side stream treatment, the complete system is beneficial over ammonia recovery and wastewater treatment as separate systems. K E Y W O R D S allocation, ammonia, ammonium sulfate, circular economy, fertilizer, nutrient recovery 1 INTRODUCTION (Inter)national policies currently aim to advance a circular economy (CE), including efforts to take the bio-based economy a step further by focusing on recycling and reuse of products and materials to minimize waste and resource use (e.g., EC, 2015, 2019; Rijksoverheid, 2019). As part of the European Union action plan toward a CE, nutrient recycling and water-efficiency measures are addressed (EC, 2015). Globally, an increase in wastewater emissions of nitrogen (N) is predicted, at least a doubling from 2000 to 2050 (Van Drecht, Bouwman, Harrison, & Knoop, 2009). Nutrient over-enrichment, that is, eutrophication, may lead to aquatic ecosystem degradation due to algal blooms, the growth of macrophytes, and aquatic hypoxia and anoxia (as summarized by Van Drecht et al., 2009). Several countries have set nitrogen discharge limits applicable to wastewater treatment plants (WWTPs), such as the ones by the European Water Framework Directive (2000/60/EC) that calls for the implementation of the Urban Waste Water Directive (92/271/EEC) and sets discharge This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Our study provides an integrated analysis of the variability of greenhouse gas (GHG) footprints of field-grown tomatoes for processing. The global farm-specific data set of 890 observations across 14 countries over a three-year period (2013–2015) was obtained from farms grown under Unilever’s sustainable agricultural code. It represents on average 3% of the annual global production of processing tomatoes: insights can be used to help inform corporate sourcing strategies and certification schemes. The median GHG footprint ranged from 18 in Chile to 61 kg CO2-equiv per tonne of tomatoes in India, lower than results reported in other studies. We found that footprints are more consistent within countries than between them. Using linear mixed effect models, we quantified the relative influence of environmental conditions and farm management factors. Key variables were area of production and the method of fertilizer application. GHG footprints decreased with increasing area of production to a threshold of 17.4 ha. Farms using single fertilizer application methods in general had a larger GHG footprint than those using a combination of methods. We conclude that farm management factors should be prioritized for future data collection, and more stringent guidance on acceptable practices is required if greater comparability of outcomes is needed either within a scheme, such as the Unilever’s sustainable agriculture code, or between schemes.

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This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in the International Journal of Life Cycle assessment. To access the final edited and published work see