Makespaces: From Redistributed Manufacturing to a Circular Economy

Redistributed manufacturing is an emerging concept which captures the anticipated reshoring and localisation of production from large scale mass manufacturing plants to smaller-scale localised, customisable production units, largely driven by new digital production technologies. Critically, community-based digital fabrication workshops, or makespaces, are anticipated to be one hothouse for this new era of localised production and as such are key to future sustainable design and manufacturing practices. In parallel, the concept of the circular economy conceptualises the move from a linear economy of take-make-waste to a closed loop system, through repair, remanufacturing, and recycling to ultimately extend the value of products and materials. Despite the clear interplay between redistributed manufacturing and circular economy, there is limited research exploring this relationship. In light of these interconnected developments, the aim of this paper is to explore the role of makespaces in contributing to a circular economy through redistributed manufacturing activities. This is achieved through six semi-structured interviews with thought leaders on these topics. The research findings identify barriers and opportunities to both circular economy and redistributed manufacturing, uncover overlaps between circular economy and redistributed manufacturing, and identify a range of future research directions that can support the coming together of these areas. The research contributes to a wider conversation on embedding circular practices within makespaces and their role in redistributed manufacturing

Phosphorus removal from eutrophic waters with an aluminium hybrid nanocomposite

An excess of phosphorus (P) is the most common cause of eutrophication of freshwater bodies. Thus, it is imperative to reduce the concentration of P to prevent harmful algal blooms. Moreover, recovery of P has been gaining importance because its natural source will be exhausted in the near future. Therefore, the present work investigated the removal and recovery of phosphate from water using a newly developed hybrid nanocomposite containing aluminium nanoparticles (HPN). The HPN-Pr removes 0.80 ± 0.01 mg P/g in a pH interval between 2.0 and 6.5. The adsorption mechanism was described by a Freundlich adsorption model. The material presented good selectivity for phosphate and can be regenerated using an HCl dilute solution. The factors that contribute most to the attractiveness of HPN-Pr as a phosphate sorbent are its moderate removal capacity, feasible production at industrial scale, reuse after regeneration and recovery of phosphate.The authors acknowledge the Foundation for Science and Technology (FCT) Project SFRH/BD/39085/2007 for the financial support

Guiding principles for the development and application of solid-phase phosphorus adsorbents for freshwater ecosystems

While a diverse array of phosphorus (P)-adsorbent materials is currently available for application to freshwater aquatic systems, selection of the most appropriate P-adsorbents remains problematic. In particular, there has to be a close correspondence between attributes of the P-adsorbent, its field performance, and the management goals for treatment. These management goals may vary from a rapid reduction in dissolved P to address seasonal enrichments from internal loading, targeting external fluxes due to anthropogenic sources, or long term inactivation of internal P inventories contained within bottom sediments. It also remains a challenge to develop new methods and materials that are ecologically benign and cost-effective. We draw on evidence in the literature and the authors’ personal experiences in the field, to summarise the attributes of a range of P-adsorbent materials. We offer 'guiding principles' to support practical use of existing materials and outline key development needs for new materials

Phosphate and ammonium removal by constructed wetlands with horizontal subsurface flow, using shale as a substrate

The objective was to investigate the performance of constructed wetlands with horizontal subsurface flow, using shale as a substrate, in removal of phosphate (P) and ammonium (N) from sewage. Shale was selected on the basis of its physico-chemical properties and its potential for P removal, investigated in an earlier study. A laboratory-scale constructed wetland system (CWS) employing horizontal subsurface flow was set up in a greenhouse, with and without Phragmites australis (reeds), and its capacity for simultaneous phosphate and ammonium removal from a synthetic sewage was monitored over a period of ten months. Both the planted and unplanted systems showed an extremely high P removal of 98–100% over the whole period of investigation. Ammonium N was also completely removed in the planted tanks, whereas in the unplanted ones the rates of removal varied between 40 and 75%; removal of nitrate N varied between 85 and 95% in planted and between 45 and 75% in unplanted tanks. pH, Eh and temperature did not differ significantly among planted and unplanted tanks, but the inlet Eh was correlated with P removal (r2 = 0.73; p &amp;lt; 0.05). The presence of Phragmites australis contributed significantly (p &amp;lt; 0.05) to P and N removal. In addition the plants showed excellent growth (up to 2 m in the first year), with good root and rhizome development, and showed potential for heavy metal removal. It was concluded that the shale-based system (which uses a readily available material) shows promise as a substrate for constructed wetland systems.</jats:p