Wastewater-based surveillance (WBS) allows the analysis of pathogens, chemicals or other biomarkers in wastewater to derive unbiased epidemiological information at population scale. After re-gaining attention during the SARS-CoV-2 pandemic, the field holds promise as a surveillance and early warning system by tracking emerging pathogens with pandemic potential. Expanding the current toolbox of analytical techniques for wastewater analysis, we explored the use of Hyperplex PCR (hpPCR) to analyse SARS-CoV-2 mutations in wastewater samples collected weekly in up to 22 sites across Sweden between October 2022 and December 2023. The samples were tested using a probe panel ranging from 10- to 18-plex, continuously adapted within 1–2 weeks to quantify relevant mutations of concern over time. For cross-validation, the samples were simultaneously analysed with commonly used methods including quantitative PCR (qPCR) and next-generation sequencing (NGS). hpPCR is demonstrated herein to provide (1) systematic single nucleotide specificity with a straightforward probe design, (2) high multiplexity with minimal panel re-optimization requirements and (3) 4–5-week earlier mutation detection relative to NGS with comparable performance of mutation frequency quantification (Pearson r = 0.88, n = 50). Hence, hpPCR is shown to be a powerful complementary tool to the current workflow involving NGS and qPCR by facilitating the assembly of dynamic high-plex panels compatible with high-frequency monitoring of multiple key pathogens and/or variants in WBS.

Volatile fatty acids (VFAs) are platform chemicals with a higher value with wide applications. The feasibility of producing high-purity VFAs from source-separated wastewater using mixed-culture fermentation and membrane techniques was investigated. Batch studies were conducted for VFA production from blackwater and food waste under acidic and alkaline conditions. The VFA production from blackwater was higher at initial pH 9 with yield of up to 0.82 ± 0.03 gCOD/gCOD_fed due to higher buffer capacity, homogeneity, and biodegradability. The highest VFA yield from food waste was 0.36 ± 0.02 gCOD/gCOD_fed at initial pH 5. VFAs from the blackwater were dominated by acetic acid (up to 93 %), regardless of pH VFAs from the food waste were dominated by butyric acid (up to 76 %) and propionic acid (up to 52 %) at pH 5 and 9, respectively. Both the substrate types and pH influenced the microbial communities of the fermentation reactors. Bacteroides (up to 40 %) and Atopostipes (up to 51 %) were dominant genii for blackwater at initial pH 5 and 9, while Clostridium_sensu_stricto clusters (up to 58 %) and Romboutsia (up to 37 %) dominated food waste fermentation microbial communities at pH 5 and 9, respectively. VFAs were separated and purified with nanofiltration (NF) and reverse osmosis (RO). NF produced high-purity, but low-concentration permeate (900 −1500 mgCOD/L) at 50 % permeate recovery (with up to 42 % of acetic acid permeating the NF membrane). A higher concentration of pure VFAs (3x higher) was achieved with a subsequent step of RO. The study highlights the feasibility of the recovery of functional chemicals from waste.

Wastewater monitoring is highly efficient in SARS-CoV-2 surveillance for tracking virus spread through travel, surpassing traditional airport passenger testing. This study explored the links between SARS-CoV-2 contents and variants from aircraft to city, assessing the impact of detected variants from international travellers versus the local population. A total of 969 variants using next-generation sequencing (NGS) were examined to understand the links between—aircraft, Arlanda airport, wastewater treatment plants (WWTPs), and Stockholm city—and compared these to variants detected in Stockholm hospitals from January to May 2023. SARS-CoV-2 contents in WWTPs reflected local infection rates, requiring analysis from multiple plants for an accurate city-wide infection assessment. Variants initially detected in aircraft arriving from China did not spread widely during the study period. RT-qPCR is adequate for the detection of specific variants in wastewater, including Variants Under Monitoring. However, NGS remains a powerful method for identifying novel variants. Wastewater monitoring was more effective than clinical testing in the early detection of specific variants, with notable delays observed in clinical surveillance. Furthermore, a broad range of variants are detected in wastewater that surpasses clinical tests. This underscores the vital role of wastewater-based epidemiology in managing future outbreaks and enhancing global health security.

Global usage of pharmaceuticals has led to the proliferation of bacteria that are resistant to antimicrobial treatments, creating a substantial public health challenge. Here, we investigate the emergence of sulfonamide resistance genes in groundwater and surface water in Patna, a rapidly developing city in Bihar, India. We report the first quantification of three sulfonamide resistance genes (sulI, sulII and sulIII) in groundwater (12-107 m in depth) in India. The mean relative abundance of gene copies was found to be sulI (2.4 x 10(-2) copies/16S rRNA gene) > sulII (5.4 x 10(-3) copies/16S rRNA gene) > sulIII (2.4 x 10(-3) copies/16S rRNA gene) in groundwater (n = 15) and surface water (n = 3). A comparison between antimicrobial resistance (AMR) genes and wastewater indicators, particularly tryptophan:fulvic-like fluorescence, suggests that wastewater was associated with AMR gene prevalence. Urban drainage channels, containing hospital and domestic wastes, are likely a substantial source of antimicrobial resistance in groundwater and surface water, including the Ganges (Ganga) River. This study is a reference point for decision-makers in the fight against antimicrobial resistance because it quantifies and determines potential sources of AMR genes in Indian groundwater.

This study investigated the efficiency of the treatment processes of wastewater treatment plants (WWTPs) to remove severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and pepper mild mottle virus (PMMoV) from the wastewater and sewage sludge, as well as the influence of the mode of operation on the quality of the treated wastewater. SARS-CoV-2 and PMMoV were detected and quantified at different stages of the wastewater and sludge treatment process of three major WWTPs in Stockholm, Sweden. The results showed that primary, biological, and advanced membrane treatment processes are effective in removing SARS-CoV-2 from the wastewater with removal efficiencies of 99–100 % for all WWTPs, while the virus was accumulated in the primary and waste-activated sludges due to higher affinity to biosolids. Operation strategies such as bypass reintroduced the virus into the treated wastewater. The WWTPs achieved relatively low PMMoV removal efficiencies (63–87 %) most probably due to the robust capsid structure of the virus. Anaerobic digestion could not completely remove SARS-CoV-2 and PMMoV from the sludge leading to increased levels of SARS-CoV-2 and PMMoV in dewatered sludge. The study gives an overview of WWTPs’ role in tackling pathogen spread in society in the event of a pandemic and disease breakout.

Shifting the concept of municipal wastewater treatment to recover resources is one of the key factors contributing to a sustainable society. A novel concept based on research is proposed to recover four main bio-based products from mu-nicipal wastewater while reaching the necessary regulatory standards. The main resource recovery units of the pro-posed system include upflow anaerobic sludge blanket reactor for the recovery of biogas (as product 1) from mainstream municipal wastewater after primary sedimentation. Sewage sludge is co-fermented with external organic waste such as food waste for volatile fatty acids (VFAs) production as precursors for other bio-based production. A por-tion of the VFA mixture (product 2) is used as carbon sources in the denitrification step of the nitrification/denitrifica-ti on process as an alternative for nitrogen removal. The other alternative for nitrogen removal is the partial nitrification/anammx process. The VFA mixture is separated with nanofiltration/reverse osmosis membrane technol-ogy into low-carbon VFAs and high-carbon VFAs. Polyhydroxyalkanoate (as product 3) is produced from the low -carbon VFAs. Using membrane contactor-based processes and ion-exchange techniques, high-carbon VFAs are recovered as one-type VFA (pure VFA) and in ester forms (product 4). The nutrient-rich fermented and dewatered bio-solid is applied as a fertilizer. The proposed units are seen as individual resource recovery systems as well as a concept of an integrated system. A qualitative environmental assessment of the proposed resource recovery units confirms the positive environmental impacts of the proposed system.

Volatile fatty acids (VFAs) production is attracting interest as a sustainable approach to maximize resource recovery from organic wastes. This study explored the interlink between long-term system resilience of VFA production from primary sludge (PS) and external organic waste (OW) without pH control and the microbial community dynamics as well as the effect of substrate variability. The study elucidated the practicality of using VFA-rich effluent as a carbon source for wastewater denitrification. A 15 L bench-scale semi-continuous reactor was operated for 315 days with a feed of 70% v/v PS and 30% v/v OW and scaled up to a 2 m3 pilot-scale continuous reactor operated for 264 days. In the bench-scale study, the system was resilient with VFA production of up to 24,700 +/- 400 mg COD/L and a yield of 506 +/- 25 mg COD/g VSfed. The VFA composition was dominated by caproic acid up to 62% w/w. In the pilot-scale reactor, substrate variability influenced VFA production with a concentration of up to 21,500 +/- 500 mg COD/L. The system was shown to be economically viable. The microbial community was dominated by Lachnospiraceae, Streptococcaceae and Comamonadaceae. The relative abundance of Lachnospiraceae gave a strong positive statistical correlation with caproic acid concentrations. The VFA-rich effluent exhibited a higher specific denitrification rate than methanol and acetate. Moreover, a continuous denitrification experiment with real nitrified wastewater resulted in a high nitrate removal efficiency with a maximum of 98%. The study demonstrates the production of bio-based products from organic wastes as alternatives to fossil-based products.

Prospective life cycle assessment (LCA) studies are widely used for evaluating emerging resource recovery systems. Simulations, engineering-based process calculations and stoichiometric methods are frequently used methods to generate life cycle inventory (LCI) in prospective LCAs. The engineering-based upscaling calculation is an efficient method for LCI generation requiring fewer resources than simulations. This study aims to test an engineering-based upscaling method for LCI generation and adapt it to biochemical resource recovery processes. The method's validity for biochemical resource recovery processes was tested using data for biogas generation by anaerobic digestion in laboratory, pilot, and full scales, and using a combination of lab-scale data and kinetic equations. Biogas generation was chosen for two reasons: (1) there are several emerging technologies based on anaerobic digestion with products other than biogas, and (2) data is available for different scales. The results showed, a substantial difference between the methane production amount in actual and conceptual plants, is an important cause of the variation in impact category results. Different estimations of fugitive emissions have an important impact on the global warming potential results. Combination of lab-scale data and kinetic equations approximates best with the actual plant for the abiotic depletion, eutrophication, freshwater aquatic ecotoxicity, global warming and photochemical ozone creation potentials. The results are sensitive to biogas generation amount in several categories.

Resource recovery from waste contributes to the transition to a sustainable society. Municipal organic wastes have enormous potential for resource recovery due to the inherent organic content which makes it possible to obtain bio-based chemicals and bioenergy. In view of this, the focus of the current study was on the bio-based recovery of carbon from municipal organic wastes by exploring process optimization and microbial community dynamics of existing and new technologies for the recovery of bio-based products. The study involved two parts: 1) biogas production through direct anaerobic granule-based treatment of mainstream municipal wastewater; and 2) production of bio-based platform chemicals in the form of volatile fatty acids (VFAs) from sewage sludge and other municipal organic wastes through mixed microbiome co-fermentation. This Ph.D. project demonstrated a waste-to-value approach to shifting wastewater treatment plants to biorefineries for recovering valuable carbon resources through both direct anaerobic treatment of municipal wastewater and co-fermentation of municipal organic waste. The application of VFAs for other processes could lead to a bio-based production platform as an alternative to fossil-based processes.

Resursåtervinning från avfall bidrar till omställningen till ett hållbart samhälle. Kommunalt organiskt avfall har en enorm potential för resursåtervinning på grund av det inneboende organiska innehållet som gör det möjligt att få fram biobaserade kemikalier och bioenergi. Med tanke på detta låg fokus för den aktuella studien på biobaserad återvinning av kol från kommunalt organiskt avfall genom att utforska processoptimering och dynamik hos mikrobiella samhällen hos befintliga och nya teknologier för återvinning av biobaserade produkter. Studien omfattade två delar: 1) biogasproduktion genom direkt anaerob granulatbaserad rening av kommunalt avloppsvatten; och 2) produktion av nya plattformskemikalier i form av flyktiga fettsyror (VFA) från avloppsslam och annat kommunalt organiskt avfall genom samfermentering av blandad mikrobiom. Detta Ph.D. projekt visade på ett avfall till värde synsätt på att förvandla avloppsreningsverk till bioraffinaderier för att återvinna värdefulla kolresurser genom både direkt anaerob behandling av kommunalt avloppsvatten och samjäsning med kommunalt organiskt avfall. Tillämpningen av VFA för andra processer skulle kunna leda till en biobaserad produktionsplattform som ett alternativ till fossilbaserade processer.

Alkaline co-fermentation of primary sludge and external organic waste (OW) was studied to elucidate the influence of substrate ratios and long-term system robustness and microbial community dynamics using batch and semi-continuous reactors. Volatile fatty acid (VFA) production increased with increasing OW fraction in the substrate due to synergistic effects of co-degradation. VFA production at pH 10 increased up to 30,300 mgCOD/L (yield of 630 mg COD/gVS_fed) but reduced over time to ≈10,000 mgCOD/L. Lowering pH to 9 led to the restoration of VFA production with a maximum of 32,000 mg COD/L (676 mg COD/g VSfed) due to changes in microbial structure. VFA was composed mainly of acetic acid, but propionic acid increased at pH 9. The microbial community was dominated by Bacillaceae (34 ± 10%) and Proteinivoracales_uncultured (16 ± 11%) at pH 10, while Dysgonomonadaceae (52 ± 8%) was enriched at pH 9. The study demonstrated a zero-waste strategy that turns organic wastes into bio-based products.