The dataset presented here consists of raw data on the quality of influent greywater generated from residential buildings (100 PE) and the effluent quality of greywater after treatment using a constructed wetland that was built in 2001. A total of 15 samples of influent and effluent samples were taken between February 2023 and Jan 2024, in different months to assess seasonal variations. This 2023-2024 data was compared with the few existing effluent quality data from 2001-2014. 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.

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.

This study evaluated a 23-year-old hybrid treatment wetland (HTW) treating greywater from a residential building in Norway using historic monitoring (2001–2014) and recent sampling campaigns (2023–2024), representing one of the longest documented systems operating in a cold-climate setting. The system consisted of an aerobic vertical flow filter with Filtralite®, and an anaerobic horizontal flow filter with Filtralite®P for enhanced phosphorus removal. Recent findings (2023–2024) show improved organic matter removal, with >98% BOD reduction and effluent BOD consistently <2 mg/L. However, nutrient removal declined over time, with effluent total nitrogen of 3.3–5.6 mg/L (59–74%). Total phosphorus increased from 0.02–0.08 mg/L (2001–2008) to 0.15–0.45 mg/L (2014–2024), indicating partial exhaustion of the Filtralite®P media. The HTW achieved effective log reductions of 1.6–3.4 for E. coli, 2.1–3.4 for enterococci, 1.6–3.1 for Clostridium perfringens, and 2.0 for Pseudomonas aeruginosa. Legionella spp. remained below detection limits, and Campylobacter was not detected. A quantitative microbial risk assessment (QMRA) showed the annual risk of infection was <10⁻⁴ for E. coli and Clostridium perfringens. The HTW met Norwegian discharge standards of BOD <20 mg/L, phosphorus <1 mg/L, E. coli <100 MPN/100 mL, and complied with EU standards for agricultural water reuse.

This study investigated the performance of the vertECO® green wall system with lightweight expanded clay aggregate (LECA) and biochar-pumice media in treating greywater from an urban city district (1000 residents) under Scandinavian climate conditions. Over one year, the system effectively removed organic matter, achieving 90–97 % of biological oxygen demand (BOD) reduction and 56–94 % for total suspended solids (TSS). However, nitrogen and phosphorus removal were inconsistent and low. Significant reductions of up to 5.1 Log₁₀ of Escherichia coli (E. coli), 4.0 Log10 of enterococci, 4.5 Log10 of Pseudomonas aeruginosa, and 2.7 Log10 of Clostridium perfringens were observed, while Legionella and Campylobacter were not detected. Cold temperatures (<5 °C) and vegetation had a minimal impact on the treatment performance. Among 17 plant species, Carex nigra, Armeria maritima, Lythrum salicaria, and Menyanthes trifoliata, Comarum palustre, Caltha palustris, and Iris sibirica showed high resilience. Despite the effective treatment of organic matter and pathogenic microorganisms, the average effluent quality did not meet the European Commission's Class A requirement (≤10 mg/L for BOD and TSS, ≤5 NTU for turbidity, and ≤ 10 CFU/100 mL for E. coli) for the reuse of reclaimed water in agriculture. Moreover, the microbial quality of the effluent indicated the necessity of a hygienisation step and protective measures to reduce infection risks if such a green wall system is placed in a public setting. 

Greywater originates from kitchen sinks, dishwashers, handbasins, showers, and laundry. Greywater can account for 70–90% of the domestic wastewater volume and contains organics, nutrients, pathogenic microorganisms, micropollutants, and microplastics. Effective treatment can unlock the potential of greywater for non-potable reuse purposes like urban landscaping or irrigation. The overall aim of this thesis was to investigate on-site greywater treatment systems which included on-site systems, two green walls, and a treatment wetland, and investigate the treatment in terms of organic matter, nitrogen (N), phosphorus (P), pathogenic microorganisms and microplastics (MPs), including the potential resource recovery and safe reuse of greywater.

Among the eight on-site systems (1–5 persons) investigated, commercial systems included three type A, two type B, and C system. Type D was a conventional sand filter. After the pre-treatment septic tanks, the treatment unit of type A consisted of a geotextile-fitted trickling filter over a sand bed, type B contained a mineral wool filter, and type C had fine-meshed plastic filters. The two green wall studies were conducted at a testbed facility, RecoLab, which received greywater from a newly developed urban city district (ca 1000 people). The treatment of an indoor vertical flow (VF) green wall with five filter materials (pumice, biochar, hemp fiber, spent coffee grounds, and composted fiber soil (a paper industry byproduct)) was investigated with the flow rates of 4.5, 9, and 18 L/d. The outdoor horizontal flow (HF) green wall with four levels filled with biochar, pumice, and LECA as filter material was investigated for one year, using a subsurface horizontal flow of 430 L/d. A long-term evaluation of the performance of a constructed wetland for treating greywater from a residential building (ca 100 people) in Norway was conducted, using data from the period 2001–2024. The constructed wetland consisted of a biofilter with Filtralite® material and a horizontal subsurface filter with Filtralite®P, for enhanced phosphorus removal.

The treatment efficiency of the systems was highly influenced by the filter material and flow rates, while seasonal temperature changes had a low impact. All the systems demonstrated effective treatment of greywater and met the local discharge guideline of 80% BOD reduction and <3mg/L of P in the effluent. However, only the VF green wall and constructed wetland could produce an effluent with <1 mg P/L, a limit for facilities located in sensitive areas. Among the studied filter materials, sand, biochar, and Filtralite® were the most efficient (log10 reduction up to 4) in the bacteria Escherichia coli, enterococci, Clostridium perfringens, Pseudomonas aeruginosa, Legionella spp., and met the European Commission’s guideline for reuse of reclaimed water in agriculture. The quantitative microbial risk assessment (QMRA) on effluent greywater from the constructed wetland, for multiple exposure scenarios (16 exposures/year) of accidental ingestion of 1 mL, indicated safe reuse in a water cascade during the summer season with regard to E. coli and C. perfringens. In addition, using TED-/Py-GC/MS, high variability of MPs was observed in greywater from the different sources of generation, while all the filter material of the respective treatment systems effectively retained the MPs, except for mineral wool and hemp.

The findings of this thesis could contribute to the development of a more resource-efficient wastewater management and Water-Food-Energy nexus by demonstrating the potential of decentralized greywater treatment systems.

Minireningsverk blir ett alltmer populärt alternativ för behandling av källsorterat BDT-vatten. Vi utvärderade prestandan hos åtta BDT-vattenanläggningar (tre olika typer av minireningsverk och en markbädd) med avseende på rening av organiskt material, näringsämnen, mikroorganismer och mikroplaster. Den mest effektiva behandlingen visade sig vara i markbädden. De flesta minireningsverk uppnådde >80% BOD-reduktion, vilket är reningskravet för BDT-vatten enligt Havs- och vattenmyndigheten. Dock var reningseffektiviteten för E. coli och enterokocker låg, vilket tyder på att det eventuellt behövs ett desinfektionssteg i fall BDT-vattnet ska återanvändas.

Eight on-site greywater treatment facilities of four different types (A, B, C and D) were investigated. Three were commercially available package plants (A–C) and one was a conventional sand filter (D). The treatment unit of Type A consisted of a geotextile-fitted trickling filter and a sand filter bottom layer, the Type B consisted of packs of fibrous mineral wool filter materials, and the Type C consisted of a fine-meshed plastic filter. The treatment systems were assessed in terms of their removal efficiency for organic matter (e.g. BOD, COD, TOC), nutrients (nitrogen and phosphorus), surfactants, indicator bacteria (E. coli and enterococci) as well as microplastics. Systems A and D effectively reduced organic matter by >96% BOD, >94% COD and >90% TOC. Their effluent BOD was <29 mg/l. The BOD reduction in the treatment facilities of types B and C was in the range of 70–95%. Removal of anionic surfactants was >90% with effluent concentration <1 mg/l in all facilities. In general, the treatment systems were ineffective in removing E. coli and enterococci; the most efficient was the sand filter (type D), achieving 1.4–3.8 log10 for E. coli and 2.3–3.3 log10 for enterococci. Due to the high E. coli in the effluents, all the on-site systems were classified as Poor (score: 0–44) according to the water quality index (WQI) assessment. In two of the studied facilities, nine microplastic polymers were targeted (i.e. PVC, PS, PET, PE, PC, NG, PMMA, PP and PA6) and analyzed using the thermal extraction desorption gas chromatography-mass spectrometry (TED-GCMS) technique. PVC, PS, PET and PA6 were commonly detected in the influent and effluent. The effluent quality from type A and D systems was found to comply with the European Commission’s guideline for the reuse of reclaimed water except for the indicator bacteria concentration.

Green walls in urban environments can be both an aesthetic feature and be of practical use in greywater treatment. This study evaluates the effect of different loading rates (4.5 l/d, 9 l/d, and 18 l/d) on the efficiency of treating actual greywater from a city district in a pilot-scale green wall with five different filter materials as substrates (biochar, pumice, hemp fiber, spent coffee grounds (SCG), and composted fiber soil (CFS)). Three cool climate plant species, Carex nigra, Juncus compressus, and Myosotis scorpioides, were chosen for the green wall. The following parameters were evaluated: biological oxygen demand (BOD), fractions of organic carbon, nutrients, indicator bacteria, surfactants, and salt. Three of the five materials investigated – biochar, pumice, and CFS - showed promising treatment efficiencies. The respective overall reduction efficiencies of BOD, total nitrogen (TN) and total phosphorus (TP) were 99%, 75%, and 57% for biochar; 96%, 58%, and 61% for pumice; and 99%, 82% and 85% for CFS. BOD was stable in the biochar filter material with effluent concentrations of 2 mg/l across all investigated loading rates. However, higher loading rates had a significantly negative effect on hemp and pumice for BOD. Interestingly, the highest loading rate (18 l/d) flowing over pumice removed the highest levels of TN (80%) and TP (86%). Biochar was the most effective material in removing indicator bacteria, with a 2.2–4.0 Log10 reduction for E. coli and enterococci. SCG was the least efficient material, giving a higher BOD in the effluent than in the influent. Therefore, this study presents the potential of natural and waste-derived filter materials to treat greywater effectively and the results can contribute to the future development of nature-based greywater treatment and management practices in urban areas.

The dataset presented here consists of raw data on the quality of influent and effluent greywater from eight on-site greywater treatment systems situated in Södertälje municipality, Sweden. These on-site treatment systems included three types of commercially available package plants and one sand filter. The influent and effluent samples were taken as grab samples between August 2020 and December 2021 and analysed for organic material, nutrients, pathogens, anionic surfactants, salt and (for two of the eight on-site systems) microplastics. Supporting parameters, e.g. suspended solids and pH, are also included. Further, for microplastics, results from blank samples are included.

This dataset was used to evaluate the treatment efficiency of the on-site greywater treatment systems and to assess the suitability of the treated water for reuse.

Datasammanställningen som presenteras här innehåller rådata från provtagningar som utfördes vid åtta enskilda anläggningar för behandling av bad-, disk- och tvättvatten (BDT) i Södertälje kommun. Prover togs från tre typer av minireningsverk och en markbädd för BDT rening. Stickprover togs från inkommande och utgående vatten mellan augusti 2020 och december 2021 och analyserades på organisk substans, näringsämnen, indikatorbakterier, anjoniska tensider, salt och (för två av anläggningar) mikroplast. Mätningar på andra parametrar såsom pH och suspenderat material är inkluderade. För mikroplast inkluderas dessutom resultat på blankprover.

Detta dataset har använts för att utvärdera reningseffektiviteten av de enskilda BDT-vattenanläggningarna och för att bedöma om det renade vattnet skulle kunna återanvändas.