Stormwater can have environmental impacts because it causes various pollutants to be released into the environment during precipitation events. This study quantifies the flow of different metals through an ultrafiltration membrane unit during stormwater treatment and investigates the possibility of reusing treated stormwater both as non-potable and potable purposes and of metal recovery from the backwash water obtained from membrane cleaning. The stormwater used for the ultrafiltration experiments was sampled in three catchments during different rain events. The results indicate that the permeate quality complied with most of the parameters for potable water as stipulated by the Swedish Food Agency, except in respect of manganese, nitrate and ammonia concentrations from permeate from stormwater samples originating from road runoff. The backwash water from the membrane cleaning contained metals in high concentrations, e.g. average copper concentrations were 5.2 times higher in the backwash than in the feed. Recovering metals like Cu, Ni, and Zn from backwash water could be a sustainable process, as stormwater transports 0.03 %, 0.01 %, and 0.04 % of their annual production in high-extraction countries, provided operational costs and logistics are feasible.

After energy recovery from blackwater via anaerobic digestion, technologies such as struvite precipitation and ammonia stripping can be used to enhance nutrient recovery. However, the presence of suspended solids, organics and metals, can negatively impact the nutrient recovery processes. This study examined the treatment of digested blackwater, applying either a ceramic microfiltration membrane or a drum filter, operating in parallel in a source-separated wastewater plant. The digestate as well as the permeates from the membrane and drum filter were sampled regularly and evaluated. In general, the ceramic membrane proved to be more efficient in improving the quality of digested blackwater in comparison to the drum filter. The ceramic membrane reduced total suspended solids to below the detection limit, while the drum filter achieved 74 % removal. The membrane removed 74 %, 85 % and 76 % of TOC, BOD7 and COD-Cr, respectively, higher than the corresponding treatment with the drum filter, which removed 41 %, 42 % and 34 %, respectively. No significant differences in phosphate and ammonium concentrations (P-value = 0.05), before and after both treatment methods were observed. The membrane removed particulate-bound metals (As, Cd, Cr, Cu, Ni, Pb and Zn) up to 25 %, 95 %, 87 %, 95 %, 66 %, 90 % and 98 %, respectively. The drum filter achieved lower removal for particulate-bound As, Cd, Ni, Pb and Zn for 25 %, 79 %, 44 %, 56 % and 86 %, respectively. The removal of metals is critical to maintain struvite purity and prevent the struvite contamination due to co-precipitate of these metals.

This study involved a survey of Swedish water utilities to evaluate their pipe-network data-collection objectives, usage, storage, and exchange routines. Factors impacting data integration (and the associated benefits) were also identified. Results showed that current data storage and exchange routines can be augmented to support commonly identified objectives and data utilisation needs, especially in larger water utilities. Levels of awareness of the opportunities for and benefits gained through asset management processes and data integration varied between utilities. Further research on the benefits of data integration in pipe network asset management is required to develop an evidence base on benefits accrued in practice, especially considering metadata, the diversity of legacy systems still in operation, costs and policy use.

In this study, the spatial relationship between critical pipes identified using edge-based centrality measures and pipes with higher failure probability-based vulnerability indicators were analysed in sanitary sewer networks. By analysing two sub-networks, one residential and the other a central network, significant spatial associations between pipes with high centrality values and those exhibiting adverse conditions (poor CCTV grades, previous blockages, and low self-cleaning capabilities) were identified. Path-based centrality measures, particularly edge betweenness and K-path edge centrality were less influenced by weights when identifying critical pipes. In contrast, non-path-based measures like nearest neighbour edge centrality could identify localised spatial patterns between critical pipes and pipes in adverse conditions within the sewer networks investigated. The results showed that the spatial patterns between critical pipes and pipes in adverse conditions were not random and could support proactive maintenance planning and the development of more resilient networks. Additionally, the impact of network structure, connectivity, and differences in the composition of pipe attributes could contribute to variations in the strength of observable spatial associations.

A major challenge for the reuse of greywater is micropollutants. For identification and characterisation of organic pollutant levels and distribution in environmental matrices a variety of non-target screening strategies and methods(NTS) have been developed (Hollender et al., 2023). For greywater, NTS approaches were taken in only three previous studies. Eriksson et al. (2003) annotated 191 individual compounds using GC-MS in greywater from 38 people living in apartments. Gulyas et al. (2011) annotated 80 organic compounds in raw greywater using GCMS from 103 inhabitants from an eco-settlement. Gros et al. (2017) identified 31 micropollutants using UHPLC Orbitrap HRMS in greywater from small scale (>5 person) systems.In this study a qualitative NTS is performed on greywater from Helsingborg, Sweden, and Oslo, Norway. Solid phase extraction (SPE) was used as pretreatment for qualitative analysis using Ultra High Performance Liquid Chromatography with high-resolution Time-of-Flight Mass Spectrometry (UHPLC/MS/MS-QTOF). A first quantitative overview on the identified chemical profiles will be presented and discussed in the context of new sustainable techniques and strategies for greywater treatment and reuse. The results of this study will be used for design of high-sample throughput quantitative analysis of priority pollutants to monitor greywater micropollutant content. The overarching aim of this study and follow up studies is to create a shortlist of micropollutants relevant for long term monitoring in greywater treatment installations targeted for reuse of greywater. While this study is performed on relatively large systems, the resulting shortlist of micropollutants will be used to analyse micropollutant greywater quantity in small wastewater systems as well.