Climate change and urbanization have caused increased surface runoff and reduced infiltration, which together exacerbates urban flooding. The hypothesis in this study is that green engineering from renewable marine biomass is a resource-efficient approach that utilize the intrinsic properties of brown seaweed for material development and optimization to achieve functional properties with potential for stormwater management. The study focuses on understanding the structure-property relationship for material development, while making use of the entire seaweed as a resource for a 100 % yield combined with non-toxic processing. The stipes, byproducts of seaweed harvesting, were fibrillated directly without using any chemicals, at an energy consumption of 2 kWh/kg, resulting in a green paste that was subsequently diluted to set concentrations and freeze dried to obtain a porous structure. CaCl2 crosslinking of the structures was optimized to achieve a porous biomaterial with porosities between 80 % and 94 % that kept its structural integrity upon absorption via a post-crosslinking approach. The drying process was optimized to achieve dimension stability wherein a second freeze-drying cycle and solvent method resulted in structures with dimension stability, compared to the uneven shapes that was obtained for materials dried directly at room temperature. The developed porous biomaterial displayed prominent absorption capacity with deionized water and stormwater absorption capacities around 3500 % and 4000 %, respectively. The cyclic water absorption studies also confirmed that the material can withstand during multiple cycles of absorption-drying with excellent structural integrity.

Changes in stormwater, snowmelt and copper roof runoff quality on circulation through seven different pipe materials (polyvinyl chloride (PVC), polypropylene (PP), glassliner (GL), feltliner (FL), galvanized steel (GS), new concrete (NC) and old concrete (OC)) are explored for a range of parameters including total, dissolved and truly dissolved metals. Circulation through all pipe materials led to increases in pH, with levels of other basic physico-chemical parameters relatively unaffected. Both increases and decreases in all Cu, Pb and Zn fractions were observed for PVC, PP, FL and GL pipes whilst circulation through GS increased total, dissolved and truly dissolved Zn. In contrast, circulation through NC and OC led to decreases in all metal fractions (with some exceptions for dissolved and truly dissolved Cu). Overall, results indicate that contact with pipe materials can impact stormwater pollutant concentrations, and thus has implications for achieving compliance with the EU Water Framework Directive.

Exterior building materials contribute to stormwater runoff pollution but knowledge of how ecological impacts may vary between different types of building materials remains limited. This study combined chemical analyses of runoff from seven different building surface materials with toxicological response analyses as a contribution to addressing this knowledge gap. Results indicate a range of inorganic (e.g. copper, zinc) and organic substances (e.g. diisononyl phthalate, DINP, and nonylphenol) are mobilised by runoff, with concentrations varying between differing materials and rain events by up to three orders of magnitude. Toxicological analysis involving algae, daphnids and fish embryos, indicated that acute and chronic effects also varied between building materials and events, as well as species. For example, copper sheet runoff (maximum concentration 2900 µg/L) exhibited the strongest acute toxic effect on all three test organisms (≥80 % effect irrespective of event and species). Chronic reproductive effects were reported for Daphnia magna on exposure to PVC and bitumen felt roof runoff. Results show that runoff from several building surface materials commonly found in urban areas can cause acute and chronic effects on aquatic organisms. Findings could support users to identify environmentally sustainable building materials as a contribution to reducing pollution emissions from cities to receiving waters.

Urban runoff is an important conveyor of microplastics (MPs) and tyre wear particles (TWP) to receiving waters. However, knowledge of contributions by surfaces within land use type/activities is currently limited. To address this knowledge gap, runoff samples were collected simultaneously during three rainfall events in October and November 2020 at three locations in Luleå, Sweden, with different urban surfaces (parking lot, road and roof). The occurrence of MPs (by number and estimated mass) and TWP (mass) were determined using μ-FTIR and Pyr-GC/MS, respectively. MPs and TWP were found at all sites in all events, with large variations between events and sites. The highest concentrations of MPs (number) and TWP were found in road runoff followed by parking lot runoff and roof runoff. The mass concentrations of MPs did not follow the same pattern and were generally highest at the parking lot, highlighting the importance of reporting data as both mass and particle numbers to derive a complete overview of MPs and TWP behaviour. Polypropylene, polyethylene, and polyester accounted, on average, for 99 % of MP polymers (by mass and number) at all sites with common sources, including traffic (vehicle wear and tear) and littering. MPs in the <75 μm fraction contributed >50 % of the total number of MPs in parking lot runoff, >58 % in roof runoff and > 90 % in road runoff.

Enhancing sediment accumulation monitoring techniques in sewers will enable a better understanding of the build-up processes to develop improved cleaning strategies. Thermal sensors provide a solution to sediment depth estimation by passively monitoring temperature fluctuations in the wastewater and sediment beds, which allows evaluation of the heat-transfer processes in sewer pipes. This study analyses the influence of the flow conditions on heat-transfer processes at the water-sediment interface during dry weather flow conditions. For this purpose, an experimental campaign was performed by establishing different flow, temperature patterns, and sediment depth conditions in an annular flume, which ensured stable flow and room-temperature conditions. Numerical simulations were also performed to assess the impact of flow conditions on the relationships between sediment depth and harmonic parameters derived from wastewater and sediment-bed temperature patterns. Results show that heat transfer between water and sediment occurred instantaneously for velocities greater than 0.1 m/s, and that sediment depth estimations using temperature-based systems were barely sensitive to velocities between 0.1 and 0.4 m/s. A depth estimation accuracy of +/- 7 mm was achieved. This confirms the ability of using temperature sensors to monitor sediment build-up in sewers under dry weather conditions, without the need for flow monitoring.

Gully pots (GPs) are an integral urban drainage component, transferring surface runoff into piped systems and reducing sediment and contaminant load on downstream sewers and receiving waters. Sediment build-up in GPs impairs their hydraulic performance, necessitating maintenance for hydraulic function recovery. The variations in sediment accumulation rates between GPs suggested by earlier studies challenge the effectiveness of adopting a generalised maintenance frequency. This study addresses the knowledge gap regarding how various factors influence sediment contamination in GPs. The impacts of seasonal activities and traffic conditions on the contamination of sediments in 27 GPs in areas with varying traffic intensities and street features (roundabouts, intersections, and straight roads) were examined. Over one year, GPs were emptied twice, with sediments collected for winter-spring and summer-autumn accumulation periods. These sediments were analysed for 84 substances, including metal(loid)s, hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), alkylphenols, phthalates, per- and polyfluoroalkyl substances and organotins. Significant temporal changes were identified in key parameters such as electrical conductivity, total organic carbons, tungsten (W), heavy-molecular-weight PAHs (PAH-H) and diisodecyl phthalate (DIDP) in GP sediments, influenced by winter road safety measures and autumn leaf abscissions. Significantly higher concentrations of 4-tert-octylphenol, DIDP, diisononyl phthalate, antimony and W were identified in GP sediments from roundabouts compared to those at the other two street features, exclusively during the winter-spring period. This is attributed to the synergistic effect of winter road safety measures and stop-and-go traffic patterns at roundabouts. No consistent spatial and temporal patterns were identified for substance concentration and mass accumulation rates. Results underscore the potential to develop a prioritisation-based maintenance strategy as an opportunity to enhance the efficiency of GP maintenance operations, ensuring better resource allocation and reduced environmental impact.

With the global concerns on antibiotic resistance (AR) as a public health issue, it is pivotal to have data exchange platforms for studies on antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the environment. For this purpose, the NORMAN Association is hosting the NORMAN ARB&ARG database, which was developed within the European project ANSWER. The present article provides an overview on the database functionalities, the extraction and the contribution of data to the database. In this study, AR data from three studies from China and Nepal were extracted and imported into the NORMAN ARB&ARG in addition to the existing AR data from 11 studies (mainly European studies) on the database. This feasibility study demonstrates how the scientific community can share their data on AR to generate an international evidence base to inform AR mitigation strategies. The open and FAIR data are of high potential relevance for regulatory applications, including the development of emission limit values / environmental quality standards in relation to AR. The growth in sharing of data and analytical methods will foster collaboration on risk management of AR worldwide, and facilitate the harmonization in the effort for identification and surveillance of critical hotspots of AR. The NORMAN ARB&ARG database is publicly available at: https://www.norman-network.com/nds/bacteria/.