Anaerobic digestion (AD) is one of the most energy-efficient waste treatment technologies for biodegradable wastes. Owing to the increasing trend of metallic nanoparticle applications in industry, they are ubiquitous to the waste streams, which may lead to remarkable impacts on the performance of the AD process. This review addresses the knowledge gaps and summarises the findings from the academic articles published from 2010 to 2019 focusing on the influences on both AD processes of biochemical hydrogen-generation and methane-production from selected metallic nano-materials. Both qualitative and quantitative analyses were conducted with selected indicators to evaluate the metallic nanoparticles' influences on the AD process. The selected metallic nanoparticles were grouped in the view of their chemical formulations aiming to point out the possible mechanisms behind their effects on AD processes. In summary, most metallic nanoparticles with trace-element-base (e.g. iron, cobalt, nickel) have positive effects on both AD hydrogen-generation and methane-production processes in terms of gas production, effluent quality, as well as process optimisation. Within an optimum concentration, they serve as key nutrients providers, aid key enzymes and co-enzymes synthesis, and thus stimulate anaerobic microorganism activities. As for the nano-additives without trace-element base, their positive influences are relied on providing active sites for the microorganism, as well as absorbing inhibitory factors. Moreover, comparisons of these nano-additives’ impacts on the two gas-production phases were conducted, while methane-production phases are found to be more sensitive to additions of these nanoparticles then hydrogen-production phase. Research perspectives and research gaps in this area are discussed.

Purpose LCA tools are increasingly used to support decision making. However, the current generation of tools is mainly targeted at users with significant background in industrial and environmental processes. This paper presents a novel process of developing the LCA Calculator with inputs from community members embedded in a co-design process. It demonstrates how engineering tools can be developed by considering end-user perspectives and used to communicate systems thinking in infrastructure co-design. Methods The process of the LCA Calculator development was informed by the outcomes of community engagement through the co-design process. The method consists of four parts including horizon scanning of suitable technology options, LCA modelling, development of the LCA Calculator and pilot testing of the Calculator with residents from the selected case study community. The case study community are residents of a social housing estate in central London. The estate has a total of 123 flats arranged in three low-rise blocks with shared gardens and courtyards. Three technology options—wormery composting, rainwater harvesting and urban food growing—were used to illustrate the LCA methods and test the Calculator development. Results and discussion The Calculator developed in this project pushes the boundaries beyond expert users to develop a new generation of LCA tools for a wider range of decision makers. The LCA results were communicated using the LCA Calculator in a workshop as part of the co-design process. The communication process was supported by the visual language of the Calculator, information sheets of the technology options and community members’ involvement in the process of the Calculator development. The Calculator provided a solid base on which sustainable design discussions could happen. It provided to the participants valuable insights into the scale of material flow given different design choices—such as the amount of waste generated over a month or the irrigation requirements of a raised bed—and environmental impacts of these options. Conclusions A prototype version of an LCA Calculator software tool has been developed to enable rapid assessment of conceptual design of engineering systems. The LCA Calculator was successfully tested at a community workshop, enabling clear engagement between engineering design choices and resource and environmental impacts. The Calculator facilitated a two-way exchange between community members and infrastructure designers that embeds end-user perspectives in the design and implementation of the infrastructure they use, taking into account lifecycle impacts of technology and material options.

In his 2018 Stockholm prize winner lecture, Goldstein highlighted the need for Problem-Oriented Policing to be not only effective but also fair. Contributing to the development of POP, this study examines how a wider perspective on problem-solving generally, and scoping in particular, can be adopted to address some of the growing challenges in 21st century policing. We demonstrate that the concept of 'problem' was too narrowly defined and that, as a result, many problem-solving models found in criminology are ill-structured to minimise the negative side-effects of interventions and deliver broader benefits. Problem-solving concepts and models are compared across disciplines and recommendations are made to improve problem oriented policing, drawing on examples in architecture, conservation science, industrial ecology and ethics.

For the water sector to cope with rising populations and the anticipated impacts of climate change, increasing amounts of construction output are needed to build water-related infrastructure. Amidst emerging operational energy efficiencies and gradual grid decarbonisation, the relative impact and extent of embodied carbon dioxide equivalent (embodied CO2e) effected from the construction and maintenance of water sector infrastructure is likely to rise. For practitioners in the water and construction sectors, there is a growing need to be able to understand and account for embodied CO2e. However, the contribution of embodied CO2e as part of the whole life cycle impacts of water related infrastructure is disputed in the current literature, and with only a handful of studies suggesting it is important its significance is not established. This work aims to explore this issue, and provide clarity. This paper shows the calculations involved to measure the embodied and operational CO2e of Old Ford Water Recycling Plant, a small blackwater recycling treatment facility producing 574 m³/day of reclaimed water. For the analyses, embodied carbon dioxide coefficients (ECCs) are used that were provided by the water operator Thames Water Utilities Ltd (TWU), and based on its supply chain, and datasets from Ecoinvent v3.1, a commercially available assessment tool. The final aggregated carbon footprint values calculated are 1.430 kgCO2e (TWU in-house analysis) and 1.566 kgCO2e (Ecoinvent) per cubic metre of recycled water. The results show that the contribution of embodied CO2e is significant, making up 50.7% (TWU) and 77.3% (Ecoinvent) of the total carbon footprint value in each analysis. The research identified that assessments could be improved if there was higher-quality data provided by manufacturers and suppliers on the embodied CO2e content of materials, components, and equipment. This paper further illustrates differences between calculations using generic data (Ecoinvent) and supply chain data, and the difficulties involved in producing functionally equivalent life cycle inventories.