Future scenarios provide challenging, plausible and relevant stories about how the future could unfold. Urban Futures (UF) research has identified a substantial set (>450) of seemingly disparate scenarios published over the period 1997–2011 and within this research, a sub-set of >160 scenarios has been identified (and categorized) based on their narratives according to the structure first proposed by the Global Scenario Group (GSG) in 1997; three world types (Business as Usual, Barbarization, and Great Transitions) and six scenarios, two for each world type (Policy Reform—PR, Market Forces—MF, Breakdown—B, Fortress World—FW, Eco-Communalism—EC and New Sustainability Paradigm—NSP). It is suggested that four of these scenario archetypes (MF, PR, NSP and FW) are sufficiently distinct to facilitate active stakeholder engagement in futures thinking. Moreover they are accompanied by a well-established, internally consistent set of narratives that provide a deeper understanding of the key fundamental drivers (e.g., STEEP—Social, Technological, Economic, Environmental and Political) that could bring about realistic world changes through a push or a pull effect. This is testament to the original concept of the GSG scenarios and their development and refinement over a 16 year period.

The challenge of feeding nine billion people by 2050, in a context of constrained resources and growing environmental pressures posed by current food production methods on one side, and changing lifestyles and consequent shifts in dietary patterns on the other, exacerbated by the effects of climate change, has been defined as one of the biggest challenges of the 21st century. The first step to achieve food security is to find a balance between the growing demand for food, and the limited production capacity. In order to do this three main pathways have been identified: employing sustainable production methods in agriculture, changing diets, and reducing waste in all stages of the food chain. The application of an energy, water and food nexus (EWFN) approach, which takes into account the interactions and connections between these three resources, and the synergies and trade-offs that arise from the way they are managed, is a prerequisite for the correct application of these pathways. This work discusses how Life Cycle Assessment (LCA) might be applicable for creating the evidence-base to foster such desired shifts in food production and consumption patterns.

The water industry is becoming increasingly aware of the risks associated with urban supplies not meeting demands by 2050. Greywater (GW) recycling for non-potable uses (e.g., urinal and toilet flushing) provides an urban water management strategy to help alleviate this risk by reducing main water demands. This paper proposes an innovative cross connected system that collects GW from residential buildings and recycles it for toilet/urinal flushing in both residential and office buildings. The capital cost (CAPEX), operational cost (OPEX) and water saving potential are calculated for individual and shared residential and office buildings in an urban mixed-use regeneration area in the UK, assuming two different treatment processes; a membrane bioreactor (MBR) and a vertical flow constructed wetland (VFCW). The Net Present Value (NPV) method was used to compare the financial performance of each considered scenario, from where it was found that a shared GW recycling system (MBR) was the most economically viable option. The sensitivity of this financial model was assessed, considering four parameters (i.e., water supply and sewerage charges, discount rate(s), service life and improved technological efficiency, e.g., low flush toilets, low shower heads, etc.), from where it was found that shared GW systems performed best in the long-term.

Electrokinetic (EK) dewatering involves the application of a (direct current) voltage across sewage sludge, driving water under an electrical gradient from the positive electrode (anode) to the negative electrode (cathode). Researchers have shown the technique to be efficient means of driving off water from the sludge, thus improving strength and reducing volume. This paper presents an integrating framework for EK dewatering under constant voltage and constant current conditions, founded on the mathematics of simple electrical circuits and demonstrated by laboratory experimentation. The derived equations and experimental results showed that electroosmotic flow rate decreases with time when dewatering with constant voltage and is constant when constant current conditions are maintained. Having a linear relationship between flow and time, EK dewatering with constant current not only enhances the sludge dewatering efficiency, but also has the advantage of simplifying design procedures.

The national demand for water in the UK is predicted to increase, exacerbated by a growing UK population, and home-grown demands for energy and food. When set against the context of overstretched existing supply sources vulnerable to droughts, particularly in increasingly dense city centres, the delicate balance of matching minimal demands with resource secure supplies becomes critical. When making changes to "internal" demands the role of technological efficiency and user behaviour cannot be ignored, yet existing benchmarking systems traditionally do not consider the latter. This paper investigates the practicalities of adopting a domestic benchmarking system (using a band rating) that allows individual users to assess their current water use performance against what is possible. The benchmarking system allows users to achieve higher benchmarks through any approach that reduces water consumption. The sensitivity of water use benchmarks are investigated by making changes to user behaviour and technology. The impact of adopting localised supplies (i.e., Rainwater harvesting—RWH and Grey water—GW) and including "external" gardening demands are investigated. This includes the impacts (in isolation and combination) of the following: occupancy rates (1 to 4); roof size (12.5 m2 to 100 m2); garden size (25 m2 to 100 m2) and geographical location (North West, Midlands and South East, UK) with yearly temporal effects (i.e., rainfall and temperature). Lessons learnt from analysis of the proposed benchmarking system are made throughout this paper, in particular its compatibility with the existing Code for Sustainable Homes (CSH) accreditation system. Conclusions are subsequently drawn for the robustness of the proposed system.