The dataset presented here consists of raw data on the quality of influent greywater generated from an urban city district (1000 persons approx.) in Helsingborg, Sweden and the effluent quality of greywater after treatment using an outdoor green wall. A total of 8 samples of influent and effluent greywater were taken between October 2023 and June 2024, in different months to assess seasonal variations. The analyzed parameters include organic matter (e.g. TSS, BOD, COD, TOC), total nitrogen, total phosphorus, salt, and microorganisms (E. coli, enterococci, Clostridium perfringens, Legionella spp, Pseudomonas aeruginosa, and Campylobacter). Supporting parameters e.g. turbidity, pH, and conductivity are also included in the dataset.

Human excreta contains most of the nutrients consumed in diets, making its recovery essential for sustainable sanitation. Separately collecting blackwater (faeces and urine) enables efficient nutrient and energy recovery. After anaerobic digestion, blackwater produces a nutrient-rich liquid that requires transportation and sanitation for use as fertiliser; concentrating this liquid reduces transport costs and environmental impact. This study investigates nutrient concentration in blackwater digestate using a pilot-scale evaporator designed to operate with waste heat as its primary energy source. Experiments were conducted under two pH conditions (6 and 2.8). The evaporator operated at 60 °C with enhanced heat transfer and gravity-based separation, achieving volume reduction factors of 87 (pH 6) and 85 (pH 2.8). pH strongly influenced nutrient solubility (phosphorus, magnesium, calcium) and equipment leaching. Pharmaceutical residues persisted in concentrates, indicating a need for additional treatment. Final concentrates contained NPK up to 6.7%, 1.5%, and 1.2%, respectively. The specific energy consumption (SEC) increased with concentration, ranging from 0.56 kWh to 1.1 kWh at 60 °C, approximately 1.4–2.8 times higher than the theoretical value. Equipment modifications for low pH and improved material selection could enhance efficiency and regulatory compliance. Future designs may also integrate heat recovery systems to reduce energy demand and improve sustainability.

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

This paper focuses on decentralized wastewater treatment in Sweden,reviewing the current regulatory framework, treatment technologies, andnutrient recovery approaches for wastewater treatment plants (WWTPs) upto 2 000 population equivalents (PE). Sweden applies rather strictenvironmental protection standards, with phosphorus removal required evenin the smallest systems and site-specific permits governing plants above 200PE. Decentralised systems employ a wide range of technologies, fromcompact biological and chemical treatment plants to infiltration systems.Constructed wetlands are still uncommon in practice but remain an activearea of research and development. Source-separating systems andphosphorus filters enable nutrient recovery and reuse, but large-scaleimplementation remains limited. Key challenges include staff shortages, highinfiltration and inflow to ageing sewer networks, high investment demand,and the lack of organised nutrient recycling systems. Addressing thesechallenges will be crucial for strengthening the role of decentralisedtreatment in a circular and resource-efficient Swedish wastewater sector.

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.

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.

This paper provides a Panarctic review of the regulations, loads, and treatment of wastewater (WW) discharged in the Arctic region. WW regulation principles and practices vary across the Arctic nations, being based either on effluent quality criteria (Canada, Sweden and Cruise ships), recipient-based criteria (Greenland, Norway), or a combination of the two (Alaska, Faroe Islands, Finland, Iceland, Russia). Conventional centralized treatment, ranging from preliminary screening to advanced/tertiary treatment, is applied to 59% of Arctic WW. Natural centralized systems, including ponds, lagoons, wetlands, and infiltration systems, are used for the treatment of 5% of the WW in the region, while 16% is treated on-site, mostly using septic tanks, sometimes affiliated with drain fields, but small package plants and infiltration systems are also in use. Between 14–20% of Arctic WW is discharged without any treatment in line with the global regions with the highest WWT service levels. However, Arctic treatment systems frequently fail to meet regulations or have reduced requirements, and secondary treatment level or higher is accomplished for only 19% of the total WW in the Arctic region, compared to 86% in Europe and North America overall. Where treatment is absent or deficient, discharge of WW may contribute to the environmental degradation of receiving waters and pose the risk of exposure of local fauna and humans to chemical contaminants and pathogens. Ecosystem impacts have been described for communities with above 2000 inhabitants; however, more studies are needed. Most sludge in the Arctic region is landfilled or used as landfill coverage, also leaving risk of exposure. It is recommended to establish cross-regional collaboration to exchange knowledge and experience on solutions and practice, and to introduce an aligned legislation and monitoring framework to reduce the environmental footprint and the risk of exposure of WW in the region.

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.