Editorial

In March, I had the opportunity to attend the WateReuse Association's annual Symposium, held in Atlanta, Georgia, USA. As an academic who primarily works on the research side of research and development, but who also collaborates with people trying to get our best ideas out of the lab and into the world, this is my favourite kind of meeting: one with very few other academics! I mean no disrespect to my academic colleagues; I just know from experience that getting out of our offices and laboratories and talking with practitioners, implementors, regulators and potential customers is critical for understanding how what we do in water and environmental research can lead to real impact in the world. Indeed, keynote speaker A-P Hurd (founder of SkipStone, Seattle, Washington, USA) made this point in her address: that the greatest innovations come from connections and communication among the most dissimilar people. In a session on projects funded by the US Environmental Protection Agency's Small Business Innovation Research (SBIR) programme, we heard from three very different small businesses working on innovative technical solutions to enable water reuse, including recapture and reuse of condensate from cooling towers, industrial onsite treatment and reuse, and treatment for non-potable reuse at the single household level. (By way of disclosure, that last panellist is a close collaborator of mine.) What stayed with me about that session, however, was not the presentations of innovative technologies themselves, but the discussion that followed. A meeting focused on water reuse is going to skew towards an audience already sold on the concept, but I was struck by how representatives from a wide variety of places were all eager for the opportunity to host pilot systems, including urban Los Angeles, rural Tennessee, Hawaii and indigenous communities in Alaska. There is a clear demand for new and innovative technologies that enable us to use our limited (and in many cases, dwindling) water resources more efficiently. And yet, the other clear theme that emerged across these discussions is that no one seems quite sure how to make this happen. The technical challenges are not trivial, and the economic challenges loom large, but the obstacle that seems most challenging is the lack of a consistent and coherent regulatory framework to enable safe and widespread implementation of new technologies. For example, when one looks at household-level systems, the relevant authorities may depend on where the system resides and where the outputs are discharged. In some states in the United States, if the final effluent is discharged underground it may fall under the jurisdiction of the health department, but if discharged above ground, the department of environmental quality. Self-contained units that reside within the structure of the house and do not discharge anything (e.g., under-sink reuse systems) may fall under building code enforcement. Other countries have similarly complex situations, and the resulting heterogeneity can represent a significant impediment to widespread adoption. Alignment of requirements and regulations is crucial. Any such alignment must be based not only on consensus, but on the most rigorous science and the most evidence-based engineering practice. WEJ is a journal that is ‘focused at the interface between academia and industry’, where we aim to not only disseminate the highest quality research but also help accelerate its implementation, enhancing the practice of water management. In this issue, Arous et al. (2022) demonstrate the potential application of a novel trickling filter designed to treat high strength wastewaters to sufficient quality as to enable their reuse in irrigation, and to do so with a minimum input of energy. This system and others like it show great promise for enabling safe reuse of domestic wastewater in agricultural applications, and this is especially important in rural areas of developing countries that may lack both safely managed sanitation services and reliably clean and abundant water. Another approach to sourcing water for irrigation can be found in Mklimia's (2022) work, which assesses the potential of ‘pseudo-natural’ wetlands to serve as treatment systems, enabling waters polluted by poorly managed onsite sanitation in urban and peri-urban areas to also be reused in irrigation. Of course, water management entails not only the management of scarcity but also that of (unwanted) abundance. Elsewhere in this issue, Junqueria et al. (2022) present a new modelling approach to evaluating the cost-effectiveness of green infrastructure on stormwater runoff management. Importantly, their model shows the dependence of projected cost on both the specific spatial contexts and climate change projections and in doing so provides a tool for decision makers to prioritize their investments. I hope you enjoy this issue of Water and Environment Journal.