Energy production and development have impacts on non-energy sector concerns including food security, water security, and sustainable land-use. Biofuel pathways differ in the tradeoffs they present within this “energy-water-food nexus” (EWFN). In this study, we focus on algal systems in the context of these interrelated challenges. We present areas of key consideration within the EWFN for large-scale algal system planning and commercialization, consider key resource inputs and outputs in the context of traditional biofuels compared with algal biofuels, provide examples of current global practices and EWFN impacts pertaining to liquid biofuels, and discuss potential opportunities and tradeoffs in applications of algal systems to EWFN challenges. The work described here could be used as a guide for future analysis that could quantitatively evaluate algal system feasibility in terms of economic viability, spatially and temporally explicit environmental impacts and production levels, and cross-sectorial impacts.

The recovery of resources from waste streams including food production plants can improve the overall sustainability of such processes from both economic and environmental points of view. This is because resource recovery solutions will be instrumental in overcoming the grand societal challenges in relation to the Water-Energy-Food (WEF) nexus in one of many aspects. Identification, development and implementation of resource recovery solutions in an industrial setting is a challenge that requires careful assessment of environmental impacts, technology readiness level (TRL), economics as well as other implementation aspects. This manuscript will first introduce these multi-disciplinary concepts followed by four case studies that are each at a different level of technological maturity and have a unique economic value proposition. The technologies demonstrated in these case studies directly convert either food waste, waste energy or wastewater into valuable raw materials. Using the case study experience as a basis, a roadmap to commercialisation is discussed where the focus is on understanding industrial needs, the role of industrial symbiosis and the current challenges that must be overcome. To this end, the objective of this manuscript is to go beyond the purely single-faceted technical discussion and provide an insight into the multi-faceted aspects of commercialising resource recovery technology development, which would be a key pillar in realising the future circular economy in line with UN’s sustainable development goals.

The goals of ensuring energy, water, food, and climate security can often conflict. Microalgae (algae) are being pursued as a feedstock for both food and fuels—primarily due to algae's high areal yield and ability to grow on non-arable land, thus avoiding common bioenergy-food tradeoffs. However, algal cultivation requires significant energy inputs that may limit potential emission reductions. We examine the tradeoffs associated with producing fuel and food from algae at the energy–food–water–climate nexus. We use the GCAM integrated assessment model to demonstrate that algal food production can promote reductions in land-use change emissions through the offset of conventional agriculture. However, fuel production, either via co-production of algal food and fuel or complete biomass conversion to fuel, is necessary to ensure long-term emission reductions, due to the high energy costs of cultivation. Cultivation of salt–water algae for food products may lead to substantial freshwater savings; but, nutrients for algae cultivation will need to be sourced from waste streams to ensure sustainability. By reducing the land demand of food production, while simultaneously enhancing food and energy security, algae can further enable the development of terrestrial bioenergy technologies including those utilizing carbon capture and storage. Our results demonstrate that large-scale algae research and commercialization efforts should focus on developing both food and energy products to achieve environmental goals.

Pesticide and agrochemical residues in food and water are among hazardous chemicals that are associated with adverse health effects. Consequently, technologies for pesticide abatement in food and water remain in focus. Cold plasma is an emerging decontamination technology, that is being increasingly explored for the abatement of agrochemical and pesticide residue in food and water. In some cases, rapid and complete degradation of pesticide residues has come to light. Such promising results encourage exploring scale-up and commercialization. To achieve this, unraveling mechanisms involved in plasma decontamination and the nature of degradation products is needed. The present review identifies the mechanisms involved in plasma- assisted removal of pesticide residues from food and water, draws parallels with mechanism of ozone and ultraviolet technologies, investigates the chemistry of the intermediates and degradates, and identifies some future research needs. The review recognizes that mechanisms involved in plasma processes have overlapping similarities to those identified for ozone and ultraviolet light, involving oxidation by hydroxyl radical and photo-oxidation. The toxicity of intermediates and degradates in plasma processing have not received much attention. The safety aspects of end products form plasma led degradation of pesticides should be considered for practical exploitation. Identification of intermediates and degradation products, recognition of most potent plasma species, understanding the influence of co-existing entities, the energy efficiency of plasma reactors, and the process economics deserve research focus.

Supporting agriculture is crucial if food security and poverty alleviation are to be assured. In that regard two crucial aspects - water and land are central to supporting smallholder farmers. This is especially true for the Eastern Cape Province of South Africa with its high rates of poverty and food insecurity. However, attention is seldom given to the fundamental factors of farm production. Access to land for food production in the Eastern Cape is problematic, as is the water situation. It is among the driest provinces in the country, enduring extended drought conditions with resultant water scarcity challenges. This is compounded by poor adaptation strategies deployed by smallholder farmers. This study investigated the relationship between water, land and food security with respect to smallholder farmers in the Eastern Cape. It found that while both food security and incomes could be improved for these smallholder farmers if they had more access to land and water, these two factors alone are insufficient. These farmers also need access to agricultural extension services, markets, cost-effective transport and capital. Although the commercialization of these farmers is a way to improve rural livelihoods, the prevailing conditions in the province significantly inhibit this.