As urbanization accelerates, stormwater management in cities has shifted from focusing strictly on water quantity to addressing water quality. Traditionally implemented systems, such as stormwater ponds, while offering effective solutions, often require large land areas to implement, making them impractical for dense urban environments. Underground stormwater systems, like EcoVault, offer a more compact solution; however, they lack scientific studies under real-world conditions to prove their effectiveness in treating pollutants. This study evaluates the treatment performance of two parallel EcoVault systems with the same design, consisting of a sedimentation step and a filtration step. These facilities were retrofitted into two different stormwater sewer networks draining two urban catchments. The systems were assessed for their ability to treat total suspended solids, metals, nutrients, and organic pollutants from urban runoff. Over 15 rain events, the average total suspended solids (TSS) removal rate was 40% for EcoVault A and 46% for EcoVault B. The removal rates for metals varied, with EcoVault B showing better performance for average metal treatment (53% for Cu and 58% for Zn). However, neither EcoVault system removed dissolved metals, often with an increase of dissolved metal concentration in the effluent. The filtration step did not contribute to pollutant treatment, likely due to clogging and high hydraulic loading rates. The study highlighted the potential of underground stormwater treatment in areas with limited space availability, while identifying challenges such as treatment of dissolved pollutants.

This study investigates the occurrence, attenuation, and ecological risks of phthalates and pharmaceuticals in a long-operating wastewater soil infiltration system in northern Sweden. Concentrations of 15 phthalates, 67 pharmaceuticals, caffeine, and acesulfame K were measured in influent wastewater, groundwater, soil, and a downgradient pond across multiple seasons. Results showed that most micropollutant removal occurred in the unsaturated soil zone prior to groundwater recharge, possibly due to processes such as biodegradation and sorption. Substantial reductions were observed for caffeine (>99 %), carbamazepine (>96 %), losartan (>99 %), and phthalates (51 ± 72 % and 92 ± 5 %), with the higher attenuation for phthalates comparable to conventional activated sludge treatment. In contrast, compounds such as metoprolol exhibited moderate reductions (>71 %), while others showed low or even negative attenuation, including diclofenac (46 % and −180 %) and ibuprofen (33 % and −11 %). After groundwater recharge, only ibuprofen showed attenuation beyond dilution, although the mechanisms for this remains unknown. Several pharmaceuticals, including metoprolol, irbesartan, and metformin, were detected in soil samples, though it is unclear whether they were sorbed to the soil matrix or present in porewater. In downgradient surface water, diclofenac and ibuprofen exceeded risk quotient thresholds, while oxazepam surpassed the lowest predicted no-effect concentration (PNEC) in one sample, indicating ecological risks. Overall, the findings highlight both the strengths and limitations of soil infiltration systems in mitigating micropollutant contamination, emphasizing the importance of vadose zone processes while underscoring uncertainties in sorption and degradation mechanisms

A curtained stormwater storage and treatment facility was constructed in Lake Storsjön (Sweden) to treat urban stormwater runoff discharges. Over two and a half years, sediments were sampled four times across four facility zones (from inlet to outlet) in two depths to inform facility operation and polluted sediment management. Sediments were analysed for particle size distribution, metals, polycyclic aromatic hydrocarbons, and organic matter content to assess the spatial distribution of deposited sediment characteristics. Finer sediments (<0.016 mm) prevailed near the outlet, with a higher presence of fine particles in the deeper layer (10–20 cm). Substantial variations in chemical concentrations were observed, differing by up to three orders of magnitude. Higher concentrations were consistently found in the inlet zone and deeper layers (10–20 cm depth) throughout the sampling program. Combined horizontal and vertical distributions of sediment characteristics indicated a predominance of historical deposits in the sediments collected. Frequent exceedances of Predicted No-Effect Concentrations of chemicals, particularly in the inlet zone, highlighted potential risks to the aquatic environment that would result from dredging activities. This underscores the importance of considering broad mitigation strategies, including the capping of contaminated sediment, to control the environmental impacts of contaminated sediments on the lake ecosystem.

Global questions such as population growth, climate change, eutrophication or resource scarcity challenge the existing wastewater management systems. The centralized wastewater management paradigm is based on a linear model with strong lock-ins where wastewater is collected, treated and disposed. Decentralized and/or alternative local sanitation solutions with focus on resource recovery, such as urine or blackwater separation, could be considered in peri‑urban areas and small communities to increase the recovery of resources and address some of these challenges. This study explores the heuristics in the Swedish wastewater sector, examining the factors influencing municipal decisions when planning or improving sanitation services. Interviews with municipal representatives, along with official statistics and literature, revealed a dominant trend of centralizing systems by decommissioning smaller treatment plants and upgrading larger ones, motivated by system robustness, operational simplicity, cost efficiencies and environmental protection. However, decentralized or resource-recovery systems occasionally arise, driven by strong leadership, sustainability goals and constraints like limited resources. Barriers to these alternatives include economic, legislative factors (lack of requirements), technical (immature technologies, uncertainties), and organizational (lack of initiative, competence and experience) challenges, alongside sectoral inertia and a lack of clear incentives.The findings highlight the dominance of centralization heuristics, possibly because the current conditions do not yet give the practitioners the knowledge, confidence or incentives to make the change, and emphasize the importance of incorporating alternative options into early planning stages. Shared visions, strong drivers and robust leadership can foster a transition toward coexisting centralized and decentralized systems that better address emerging global challenges.

Denna artikel baseras på resultat från två studier som har undersökt hur VA-organisationer kan ta sig ur den så kallade “data-loopen” – en situation där bristfälliga data gör det svårt att använda modeller och beslutsstöd, vilket i sin tur gör att man tvekar att investera i bättre datainsamling. Artikeln presenterar ett praktiskt ramverk som visar hur man kan komma igång med datadrivet arbete i tillgångsförvaltning av VA-infrastruktur och sedan stegvis bygga vidare och skala upp. Studierna visar också att VA-organisationer faktiskt kan skapa nytta redan från början, även med ofullständiga eller osäkra data samtidigt som de kan lägga grunden för en mer mogen, datadriven tillgångsförvaltning på längre sikt.

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.

I takt med en accelererande urbanisering har dagvattenhantering i städer gått från att enbart fokusera på vattenkvantitet till att även ta hänsyn till vattenkvalitet. Traditionellt implementerade system som dagvattendammar erbjuder effektiva reningslösningar, men kräver ofta stora markområden för att implementeras vilket är en utmaning i täta stadsmiljöer. Underjordiska dagvattensystem kan erbjuda mer kompakta lösningar. Dock sakas det vetenskapliga studier som undersöker deras effektivitet när det gäller att rena dagvatten. Denna studie utvärderar reningsprestandan hos två parallella EcoVault®-system som är ett exempel på sådana prefabricerade underjordiska anläggningar. De parallella systemen har samma design och består av ett sedimenteringssteg och ett filtersteg. Anläggningar implementerades i två olika dagvattenledningsnät som avvattnar två urbana avrinningsområden i Sundvall. Systemen utvärderades med avseende på deras förmåga att rena dagvatten från suspenderade ämnen, metaller, näringsämnen och organiska föroreningar. Under 15 regntillfällen var den genomsnittliga avskiljningsgraden för totalt suspenderat material (TSS) 40% respektive 46% för de två systemem. Avskiljningsgraden för metaller varierade, där den ena anläggningen visade bättre prestanda i genomsnittlig metallrening (53% för Cu och 58% för Zn). Inget av EcoVault®-systemen renade dock lösta metaller. I stället observerades ofta en ökning av koncentrationen av lösta metaller i utflödet. Filtersteget bidrog inte till reningen av föroreningar, vilket sannolikt berodde på igensättning och den höga hydrauliska belastningen av filtret. Vattnet kom till stor del inte i kontakt med filtermaterialet utan bräddades över filtret redan vid låga (bas-)flöden. Studien visade på potentialen i underjordisk dagvattenrening i områden med begränsad tillgång till utrymme, samtidigt som den identifierade utmaningar främst gällande rening av lösta föroreningar. Dessutom visar studie att filtren sätter igen snabbt och kräver mycket underhåll vilket gör sådana underjordiska system till en ganska dyr reningsteknik.

Projektet har utvärderat avancerade tekniker för dagvattenrening som kan komplettera och införlivas i etablerade lösningar och bebyggda områden för att skapa mer yteffektiva dagvattenreningssystem. Tekniker som har undersökts är zeolitfilter, membranrening, kemisk fällning och en rasterstruktur för dammar. Avskiljning av föroreningar har varit i fokus, men projektet har även belyst aspekter som rening över tid, implementering och utvecklingsbehov.

The project has evaluated advanced stormwater treatment techniques that can complement and be integrated into established solutions and urban areas to create more space-efficient stormwater treatment systems. Zeolite filters, membrane filtration, chemical precipitation and grid structures for ponds have been investigated. For all components, treatment of stormwater pollutants has been in focus, but other aspects such as treatment over time, implementation and further need of research have been discussed.