Biogas, a gaseous mixture produced during decomposition of organic matter, is a renewable, easily generated and common byproduct of anaerobic digestion at wastewater treatment plants (WWTP), landfills and agricultural operations. There is growing interest in researching and utilizing the energy potential associated with its combustion. Siloxanes, a family of volatile organic silicon compounds, pose large impediments to biogas usage due to the formation and precipitation of silicon dioxide within combustion devices. Removal of siloxanes prior to combustion is therefore a growing endeavor. Research was performed to synthesize a representative gas stream produced from anaerobic digesters within WWTP. Methane, carbon dioxide and hydrogen sulfide were combined with humidity and gaseous siloxane in levels characteristically seen exiting anaerobic digesters. A methanol impinger train was utilized to sample the biogas composite. Gas chromatography-mass spectrometry (GC-MS) was used to determine gas-phase siloxane concentrations in the gas stream effluent for the purposes of confirming the generation of a consistent and reproducible biogas stream. / Master of Science

Clean water and renewable energy are essential requirements to build resilience towards the adverse effects of climate change and global warming. Advanced wastewater treatment options may provide a unique opportunity to recover various useful resources such as energy (biogas), fertilizers, minerals, and metals embedded in the wastewater stream. However, considerable challenges remain when it comes to designing and planning sustainable wastewater treatment systems. This thesis focuses on the avenues of energy recovery from wastewater treatment plants (WWTP), by evaluating the potential for biogas recovery from wastewater and sewage sludge treatment in WWTPs. Various available technologies for biogas recovery are examined and evaluated to understand their viability in different applications and relative performance. Further, the methodologies and tools employed to assess such energy recovery systems are evaluated, covering the technical, economic, and environmental performance aspects. A sustainability assessment framework is then developed, using appropriate sustainability indicators to assess performance. The framework is applied to a case study of a WWTP in the emerging city of Tbilisi, Georgia. A spreadsheet tool is also developed to aid the sustainability (technoeconomic and environmental) assessments for the case study. The case study results reveal a significant biogas recovery potential, with annual energy generation potential of 130 GWh from combined heat and power (CHP) recovery, and a potential to avoid 28,200 tCO2eq emissions every year, when biogas is recovered only from the wastewater. The recovery potential increases when biogas is recovered from both wastewater and sewage sludge. Further, the contribution of overall resource (energy and nutrient) recovery in WWTPs to the Sustainable Development Goals is examined. By studying the linkage of various benefits to the different SDGs, the multilateral and cross-cutting nature of benefits from resource recovery is clearly illustrated. The thesis concludes with the discussion of possible future technologies and perspectives that can enhance the sustainability of WWTPs and help transform them into Wastewater Resource Recovery Facilities (WRRFs). / Rent vatten och förnybar energi är väsentliga krav för att bygga motståndskraft mot de negativa effekterna av klimatförändringar och global uppvärmning. Avancerade avloppsreningsalternativ kan ge en unik möjlighet att återvinna olika användbara resurser som energi (biogas), gödselmedel, mineraler och metaller inbäddade i avloppsvatten strömmen. Det finns emellertid stora utmaningar när det gäller att utforma och planera hållbara reningssystem. Denna avhandling fokuserar på möjligheterna till energiåtervinning från avloppsreningsverk (WWTP), genom att utvärdera potentialen för biogasåtervinning från avloppsvatten- och avloppssrening i WWTP. Olika tillgängliga tekniker för återvinning av biogas undersöks och utvärderas för att förstå deras livskraft i olika applikationer och relativa prestanda. Vidare utvärderas de metoder och verktyg som används för att utvärdera sådana system för energiåtervinning som täcker de tekniska, ekonomiska och miljömässiga aspekterna. En ram för hållbarhetsbedömning utvecklas sedan med hjälp av lämpliga hållbarhetsindikatorer för att bedöma prestanda. Ramverket tillämpas på en fallstudie av en WWTP i den framväxande staden Tbilisi, Georgien. Ett kalkylarkverktyg utvecklas också för att underlätta bedömningarna av hållbarhet (teknisk ekonomi och miljö) för fallstudien. Resultaten från fallstudien avslöjar en betydande återvinningspotential för biogas, med en årlig energiproduktions potential på 130 GWh från kombinerad värme och kraft (CHP), och en potential att undvika 28.200 ton CO2-utsläpp varje år, när biogas endast återvinns från avloppsvattnet. Återvinningspotentialen ökar när biogas utvinns från både avloppsvatten och avloppsslam. Vidare undersöks bidraget från den totala återhämtningen av energi (energi och näringsämnen) i WWTP till målen för hållbar utveckling. Genom att studera kopplingen mellan olika fördelar till de olika SDG: erna illustreras den multilaterala och tvärgående karaktären av fördelarna med resursåtervinning. Avhandlingen avslutas med diskussionen om möjliga framtida tekniker och perspektiv som kan förbättra WWTP: s hållbarhet och hjälpa till att omvandla dem till anläggning för återvinning av resurser från avloppsvatten.

Mikroplastik (MPs) Partikel die kleiner als 5 mm sind, werden weltweit als neu identifizierte Gefahr auf die Umwelt betrachtet. Um geeignete Minderungsstrategien entwickeln zu können, werden diese neuartigen Umweltschadstoff hinsichtlich möglicher Eintragsquellen und potentieller Transportwege in der Umwelt zunehmend diskutiert. Gründe für eine notwendige Reduzierung von MPs in der Umwelt gibt es viele. Es werden dabei insbesondere das Transportverhalten in der Umwelt sowie deren Toxizität auf das System Mensch und Umwelt als Schlüsselkomponenten angesehen. Die in den letzten zehn Jahren gestiegene Nachfrage an synthetischen Textilien und der daraus resultierenden Produktionssteigerung hat zur Folge, dass diese Textilien eine Hauptquelle der MP-Verschmutzung im aquatischen System darstellen. Jedoch fehlen aktuell spezifische Informationen über die Größe und den Verbleib von faserigen Mikroplastikpartikeln (FMP), die aus gewaschenen Textilien des täglichen Lebens freigesetzt werden, wenn sie die Kläranlagen passieren und schließlich in Ökosysteme gelangen. Ziel dieser Arbeit ist es, die prävalent vorkommenden Größenfraktionen aus Polyethylenterephthalat (PET) FMPs, die aus synthetischen Fleecejacken beim Waschen in einer kommerziellen Waschmaschine freigesetzt werden, zu identifizieren und anschließend zu quantifizieren. Dabei soll ihr Vorkommen und ihr Verbleib in konventionellen Kläranlagen unter Berücksichtigung verschiedener Behandlungsstufen untersucht werden. Um den potenziellen Einfluss der PET-Faserlänge auf das Transportverhalten in Kläranlagen zu untersuchen, wurden zwei unterschiedlichen Größenfraktionen (1500 – 500 µm und 150 – 50 µm) in Batchtests miteinander verglichen. Darüber hinaus wurde in dieser Studie die Wirksamkeit der Koagulation, einem etablierten Verfahren aus der chemischen Abwasserbehandlung, auf die Eliminierung von FMP-PET-Fasern aus Abwässern untersucht. Unter Verwendung eines aus einer städtischen Kläranlage stammenden Inokulums wurde die biologische Abbaubarkeit von FMPs (PET) im Labormaßstab im Vergleich zu natürlichen (Baumwolle), regenerierten (Viskose), PET/Baumwoll-Mischgewebe und oxo-abbaubaren PET-Fasern untersucht. Zusätzlich wurde der Einfluss verschiedener Ausrüstungsverfahren (z.B. Reaktivfarbstoffe, Weichmacher und antimikrobielle Zusätze) auf die biologische Abbaubarkeit von Viskosefasern getestet. Der Waschtest ergab, dass die höchste Freisetzung von FMPs beim ersten Waschen auftrat und mit einer schrittweisen Reduzierung der Faseremission in weiteren Versuchen einherging. Bei einer Gesamtverteilung der PET-Faserlänge zwischen >1500 - 5 µm deckte die am häufigsten vorkommende massenbezogene Größenfraktion einen Bereich von 500 µm bis 50 µm ab. In einer Kläranlage konnte festgestellt werden, dass die Mehrheit der PET-Fasern unabhängig von der Größenverteilung mit partikulären Feststoffen abgeschieden werden (>90 % für Belebtschlamm und >99 % für Primärschlamm). Es konnte jedoch beobachtet werden, dass ein erhöhter Anteil kleiner Fasern (150 – 50 μm) in der flüssigen Phase verbleiben, was darauf hindeutet, dass kleineren Fasern nicht durch Kläranlagen zurückgehalten werden und schließlich in die Gewässer gelangen. Darüber hinaus konnte gezeigt werden, dass die Zugabe einer Koagulationschemikalie die Entfernung von großen PET Fasern (1500 – 500 μm) aus Abwässern geringfügig verbessern könnte; der Effekt war jedoch nicht signifikant. Die biologische Abbaubarkeit von Fasern in aquatischen Matrices nahm mit folgender Reihenfolge ab: Baumwolle ≥ Viskose > PET/Baumwollmischung > oxo-abbaubares PET ≥ PET. Dabei wiesen mit bestimmten Ausrüstungsmitteln behandelte Fasern im Vergleich zu unbehandelten Fasern einen niedrigeren Mineralisierungsgrad auf. Dieses zentrale Ergebnis unterstreicht die Bedeutung zur Berücksichtigung der Textilausrüstung bei der Bewertung des Umweltverhaltens von FMP. Dies ist die erste Studie, in der sich in der Abwasserbehandlung ausschließlich auf das Verhalten von PET-Fasern als eins der am häufigsten verwendeten Materialien in der Bekleidungsindustrie konzentriert wurde. Es konnte gezeigt werden, dass das Verhalten von textilbasierten FMPs bei der Abwasserbehandlung größenabhängig sein kann. Darüber hinaus wurde beobachtet, dass die Textilveredelung, je nach Haltbarkeit und Art des verwendeten Additivs, die Halbwertszeit von Faserschuppen in der Umwelt verlängern kann. Beide Erkenntnisse sind von großer Bedeutung, um nachhaltige Textilprodukte mit einer deutlich geringeren FMP-Emission in die Umwelt und im Hinblick auf eine funktionierende Kreislaufwirtschaft zu entwerfen. / Microplastics (MPs), plastic particles <5 mm, have been considered as global emerging environmental contaminants, triggering discussions regarding their sources, transport pathways and possible mitigation strategies, while fate and toxicity are recognized as key issues, including their potential threats to human health. The increased production and use of synthetic clothes over the last decade have placed synthetic textiles as one of the main sources of MP pollution in aquatic environments. However, there is still lack of information specifically on the size and fate of Fibrous Microplastic Particles (FMPs) released from washed daily-life products when they pass through Wastewater Treatment Plants (WWTPs) and eventually end up in the ecosystems. This thesis aims to investigate the amount and the dominant size fractions of polyethylene terephthalate (PET) FMPs released from synthetic fleece jackets during washing and to understand their occurrence and fate in conventional WWTPs, by considering different treatment stages. The potential influence of fibre length on the removal of PET fibres in WWTP was also investigated in batch tests, with two size fractions being compared, i.e. 1500 – 500 μm and 150 – 50 μm. Additionally, this study examined the efficacy of the coagulation, an established process of chemical treatment, on the elimination of FMP PET fibres from wastewaters. Finally, the present study evaluated the biodegradability of FMPs (PET) compared to natural (cotton), regenerated (viscose), PET/cotton blend and oxo-degradable PET fibres under laboratory conditions, by using inoculum from a WWTP, as well as the influence of different finishing processes (i.e. reactive dyes, softener and antimicrobial agent) on the biodegradability of viscose fibres. The washing test revealed that the highest release of PET fibres occurred in the first wash, with a consequent reduction of fibres’ emissions in sequential trials. PET fibre sheds collected with the aid of a filter cascade ranged from >1500 – 5 μm, with the most dominant size fraction in terms of mass ranging from 500 μm to 50 μm. Microscopic and gravimetric analysis revealed that when present in a WWTP, the majority of PET fibres were found to be associated to solids (>90% for activated and >99% for primary sludge), irrespective of their size fraction. However, small fibres (150 – 50 μm) were demonstrated to be retained in the liquid phase to a higher extent, indicating the likelihood of smaller fibres to pass through the WWTPs, entering eventually the water bodies. Moreover, our results showed that the addition of the coagulant chemical could slightly enhance the removal of large PET fibres (1500 – 500 μm) from wastewater effluents; however the effect was not significant. The biodegradability of fibres in aquatic environments decreased with the following order: cotton ≥ viscose > PET/cotton blend > “oxo-degradable” PET ≥ PET, while fibres treated with certain finishing agents displayed a lower mineralization level compared to the untreated, highlighting the importance of considering the textile finish when assessing the environmental behavior of FMPs. This is the first study giving emphasis solely on the behavior of PET fibres, one of the most common materials used in apparel industry, demonstrating that the performance of FMPs originated from textiles in wastewater treatments may be size-dependent. Moreover, it was shown that textile finishing might prolong the environmental half-lives of fibre sheds, depending on the durability and type of additive applied. Both findings are important when aiming at designing sustainable textile products with respect to a circular economy and considerably less FMPs emissions in the environment.

Målet med den här studien är att förhindra effektivitetssänkningar i moderna biologiska reningsanläggningar för skogsindustriella avloppsvatten. Biologiska processer är vanligtvis effektiva när det gäller att reducera lättnedbrytbart organiskt material. Eftersom den utgörs av levande mikroorganismer (MO) är tekniken känslig. Toxiska ämnen kan döda en kultur av MO. Innan de har ökat i antal igen kommer reduktionseffektiviteten att vara påverkad för en ansenlig tid framöver. I ett pappers- och massabruk finns många typer av vätskor som oavsiktligt kan hamna i reningsanläggningen. I den här studien har svartluts inverkan på reduktionsgraden studerats. Biologiska reningsverk har använts under en lång tid. De har utvecklats från att vara generella reningsverk till att bli konceptanläggningar i flera steg, där varje steg har designats för sitt eget syfte med specifika MO. I det här arbetet har ett MultiBio-koncept vid Gruvön Bruk studerats. En anläggning i laboratorieskala har byggts för svartlutsförsöken. Resultatet har jämförts mot simulerade värden och värden från bruket. När ett spill av svartlut passerar genom en MultiBio späds det ut mellan varje steg. Halten av svartlut är hög i de första stegen vilka påverkas kraftigt. I de första stegen lever snabbväxande organismer som återhämtar sig på ett par dagar. De mer känsliga aktivslamstegen finns längre bak i reningsverket och är skyddade från toxiska koncentrationer av svartlut. Endast vid försök med 24-timmarstillsatser blev koncentrationen av svartlut så hög att den påverkade MO negativt. Den biologiska processen i ett reningsverk kan störas om MO förnekas något essentiellt behov. En biologisk process har ett flertal behov, bland annat behöver aeroba MO löst syre. Eftersom syresättning av vattnet är energikrävande och kostsamt är det inte problemfritt att skapa en omgivning som ger hög effektivitet samtidigt som man strävar efter att sänka energiförbrukningen. I avhandlingen beskrivs ett tillvägagångssätt för att studera energieffektiv syresättning. / The aim of this study is to prevent efficiency reduction in modern wastewater treatment plants for forest industry effluents. Biological processes are usually efficient in reducing biodegradable organic material. Since the technique depends on living microorganisms (MO) it is sensitive. Toxic substances can kill the population. It takes considerable time for the MOs to grow in number and the treatment efficiency will be affected accordingly. In a pulp and paper mill, a number of liquors are handled that can reach the treatment plant by accident. In this study the impact of black liquor spills on treatment efficiency has been studied. Biological treatment methods have been used for a long time. They have developed from general treatment plants to multiple stage concepts, where each stage is designed for its own purpose with specific MO cultures. In this thesis, a plant with the MultiBio concept, located at Gruvön Mill in Sweden has been studied. A laboratory scale MultiBio plant has been constructed for the trials in which efficiency during black liquor exposure has been measured. The measured laboratory results were evaluated by comparing them with simulated values and a mill case. When a shock of toxic black liquor passing through a MultiBio concept, the black liquor is diluted between the compartments. The first compartments that are exposed to high concentrations of black liquor are affected negatively. The MOs in the first compartment are fast growing and recover in a few days. The more sensitive activated sludge compartments are located further on in the plant. A toxic concentration is found in the activated sludge compartments only when the duration of the spill is 24 hours or more. Denying the MOs their needs can disturb biological treatments. Among many things, a biological process needs dissolved oxygen. Since aeration is energy consuming and expensive, there is a conflict between gaining high efficiency and, at the same time, decreasing the energy consumption. In this study, an approach to saving energy for aeration is initiated.

Anthropogenic activity has caused increased concentrations of greenhouse gases (GHGs) in the atmosphere which has resulted in global warming gaining momentum. GHG emission estimates up to date are insufficient and in order to mitigate GHG emissions of anthropogenic origin fluxes of GHGs need to be mapped. The application of low-cost sensors (LCSs) as an environmental monitoring tool has been seen as a pathway with the ability to provide GHG estimates that can help us to identify sources and sinks. However, questions have been highlighted regarding the accuracy of LCSs in targeting GHGs in comparison to alternative environmental monitoring approaches. A network of LCSs with the ability to target carbon dioxide (CO2) and methane (CH4), among other environmental parameters of interest, were deployed at a wastewater treatment plant (WWTP) in Linköping, Sweden. A cross-checking procedure where LCS data were compared with data from high-precision measuring instruments UltraPortable Greenhouse Gas Analyser (UGGA) and air samples analysed with gas chromatography (GC), enabled evaluation of LCSs as an environmental monitoring tool. Despite uncertainties regarding individual sensors´ behaviour, results from this study show that LCS systems have the capability to bring valuable estimates of GHGs to the environmental monitoring field, although not yet at the precise level of reference equipment. The low cost of the LCS systems studied in this work open a range of possibilities because of their ability to provide large amounts of data on both a spatial and temporal scale that are not attainable for high-precision reference instruments. From the long-term measurements it can be concluded that the CO2 concentrations at the dewatered sludge deposit, and especially inside the screw conveyor building, are higher than global average levels of CO2. / Mänsklig aktivitet har orsakat ökade koncentrationer av växthusgaser i atmosfären vilket i sin tur har resulterat i att den globala uppvärmningen har accelererat. Estimeringar av växthusgasutsläpp har hittills varit bristfälliga och för att kunna lindra antropogena växthusgasutsläpp kartläggning av växthusgasers utbyten efterfrågas. Applicering av lågkostnads-sensorer som en ett verktyg inom miljöövervakning har setts som en möjlig väg i att tillhandahålla estimeringar av växthusgaser som kan hjälpa oss att identifiera källor och sänkor. Dock har frågor om hur precisa lågkostnads-sensorer är i jämförelse med alternativa miljöövervakningsmetoder lyfts. Ett nätverk av låg kostnads-sensorer som kan känna av koldioxid (CO2) and metan (CH4) och en rad andra miljömässiga parametrar av intresse, placerades ut på ett reningsverk i Linköping, Sverige. En procedur där sensordata ställdes mot data insamlad från de högprecisa instrumenten Ultra-Portable Greenhouse Gas Analyser och luftprover analyserande med gas kromatografi öppnade upp för möjligheten att utvärdera sensorernas prestanda. Trots osäkerheter i data gällande individuella sensorers beteende, så visar resultat från den här studien att låg kostnads-sensorsystem har kapaciteten att bidra med berikande estimeringar av växthusgaser till miljöövervakning området, dock ännu inte med samma precishet som för referensinstrument. Den låga kostnaden för lågkostnads-sensorsystemen som studeras i det här arbetet öppnar upp för en rad möjligheter tack vare att de kan tillhandahålla stora mängder data på både en spatial och temporal skala som inte är inom räckhåll för högprecisa referensinstrument. Från långtidsmätningarna kan det konstateras att koncentrationerna av CO2 vid slamavvattningslagret, och särskilt inne i skruvpressbyggnaden, är högre än det globala genomsnittsvärden för CO2 nivåer.

Wastewater treatment plants (WWTPs) are originally not constructed to remove pharmaceuticals from the wastewater. Biological treatment technologies used in many WWTPs today, e.g., activated sludge, MBBR and trickling filters, can, however, remove some pharmaceuticals well. Advanced treatment technologies, like ozonation, can be used as a complement to biological treatment for an even better removal. Käppala WWTP is not required to remove pharmaceuticals today, but is obligated to follow the development of advanced treatment technologies and prepare to implement one in the future. Additionally, a new wastewater treatment directive is under development with stronger regulations of pharmaceutical removal. Because of this, it is important to gather information about removal efficiencies for different treatment technologies in Käppala and other WWTPs. In this project, direct injection-UHPLC-Orbitrap-MS/MS was used to analyze wastewater from seven different WWTPs, including Käppala, with the aim to detect as many pharmaceuticals as possible. The removal efficiencies for 59 identified compounds, most of them pharmaceuticals, were used to evaluate the WWTPs and their treatment technologies. 55 of these compounds were detected in Käppala WWTP while 48 were detected in all seven WWTPs. In Käppala WWTP, around half of all compounds were removed with less than 20 %, including most of the compounds that is proposed to be regulated in the new wastewater treatment directive. This highlights the need for Käppala WWTP to introduce new treatment technologies. Two Swiss plants with ozonation had a removal efficiency &gt; 80 % across the whole plant for 79 % and 67 % of the compounds respectively. In the WWTPs that lacked advanced treatment technologies only 12-33 % of the compounds had a removal &gt; 80 %. One compound, chlorothiazide, did however increase 30 times across the plants with ozonation treatment. The trickling filter in one WWTP barely removed any compound with more than 20 % and was thereby the biological treatment technology with lowest removal efficiency. Activated sludge without N-removal also had a slightly lower removal of pharmaceuticals compared to activated sludge with N-removal and MBBR, possibly due to a shorter hydraulic retention time (HRT) and sludge retention time (SRT).

The overuse and misuse of antibiotics to treat bacterial infections, the release of unmetabolized residuals into the sewer system, and the incomplete removal antibiotic residues by wastewater treatment plants (WWTPs) pose a severe threat to human health. The accumulation of antibiotic residue induces selective pressure on the bacterial population, resulting in the spread of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) in water. This study investigated the degradation of different types of ARGs in water matrices using a wide variety of treatment technologies. Real wastewater samples were collected from a WWTP in urban Philadelphia and the presence of single and multidrug-resistant bacteria and resistance genes were investigated using molecular-based techniques. Subsequently, an analytical method was developed and validated for the detection and quantification of the ARGs against a range of antibiotics, such as tetracycline (TCN), ciprofloxacin (CIP), and levofloxacin (LVX). Finally, to remove the ARGs from water matrices, different conventional and advanced oxidation processes were applied. At the very onset, conventional treatment processes such as chlorine treatment was used to inactivate the E.coli resistant strains. It was observed that chlorination can potentially deactivate the ARBs by applying a lower dose and contact time. However, the effectiveness of chlorine treatment in removing all types of ARGs from water matrices was limited. For instance, no significant degradation of extracellular ARGs (e-ARGs) was observed in DI water during chlorine treatment. Subsequently, a peracetic acid (PAA) based treatment process was used to degrade the genomic and plasmid-encoded ARGs from the water matrices. Similar to chlorine treatment, no significant changes were observed in the degradation of extracellular ARGs (e-ARGs) in DI and WW. Then, the degradation kinetics of ARGs across different types (gyrAR, tetAR, qnrSR) and forms (chromosomal, plasmids) were evaluated using the Ultraviolet (UV) disinfection process. Compared to chlorination and PAA, UV treatment showed better removal efficiencies for the degradation of different types of e-ARGs in DI water. The degradation profile of e-ARGs showed 1-4 log reductions at a UV fluence of 900 mj/cm2. The i-ARGs showed similar degradation rates as compared to e-ARGs in phosphate buffer saline (PBS) at the same UV dosage. On the other hand, the regrowth potential of ARBs at low UV dosage (60–180 mJ/cm2) showed the evidence of damage repairment after several hours of exposure to light (photoreactivation) and dark conditions, making it susceptible again to the resistance spread. To resolve this issue, process parameters were optimized, and no regrowth of the ARBs were found from the higher fluence from 300 to 600 mJ/ cm2. Later, UV/ H2O2 based AOP was applied to evaluate the degradation and deactivation of the same resistant genes. The addition of H2O2 during the UV treatment produces strongly reactive •OH radicals during the treatment and showed considerable improvements in e-ARGs degradation (1.2-5 logs) compared to UV treatment alone. However, this AOP showed minimal contribution to i-ARG degradation (1-2.4 logs), possibly due to the scavenging of •OH radicals by the cellular components in PBS. In contrast to PBS, the wastewater matrix moderately enhanced the gene degradation during the treatment. In terms of plasmid degradation, the conformational differences of the supercoiled structures showed 1.2-2.8 times slower degradation rates than chromosomal ARGs. In addition, the degradation kinetics of the free residual ARGs (f-ARGs) were assessed during the treatment to reduce the AMR dissemination risk from the treated sample. This study also examined the potential of ozone (O3) based oxidation process to degrade and deactivate the extracellular and intracellular ARGs, and MGE (plasmid, intl-1) from E.coli ARBs. The degradation kinetics of the ARGs across different sizes (118-454 bps) and types were evaluated in different water matrices (DI water, PBS, and WW), and showed a significantly higher removal for chromosomal, and plasmid encoded ARGs than other treatment technologies. For the e-ARGs in DI water, 3.8-5.2 logs removal was observed at ozone dosage of 2.0 × 10-2 M.s. i-ARGs in PBS and wastewater showed nearly similar degradation (3.8-5 logs) during O3, indicating the elimination of i-ARGs was not dependent on the cellular components and effluent organic matter. Moreover, an analysis of environmental DNA (eDNA) from wastewater was conducted to examine the degradation of DNA and ARGs for different storage periods and temperatures (-20°C, 0°C, 4°C, 22±0.87°C). Result indicated that water samples kept at -20°C and 0°C showed the best performance in preventing the DNA concentration and gene degradation over time. Additionally, the effectiveness of different preservatives (Longmire buffers: LB1 and LB2, benzalkonium chloride at 0.1%, 0.01%) were investigated in preserving the DNA integrity and the gene degradation at an ambient temperature. It was found that the Longmire buffer (LB1) exhibited lowest gene degradation during the three-week storage period. In summary, this research provided a comprehensive assessment on the degradation of e-ARGs, i-ARGs, and free ARGs from water using different treatment technologies (i.e., UV, UV/H2O2, O3, PAA, chlorine). Additionally, this study suggested valuable information on optimizing the process parameters of the selected methods and developed a comparative assessment of removing the ARGs from the water matrix (DI/PBS, WW). The estimation of Electrical Energy per Order (EEO, kWh/m3) during UV and ozone treatments provided a comparison of the energy consumption for ARGs degradation in the water. Overall, the findings of this study can be useful for evaluating different types and forms (chromosomal, plasmid) of ARG degradation from water matrices and can help to reduce the risk of AMR dissemination in the environment. / Civil Engineering

The study aims to investigate an appropriate wastewater treatment process to treat domestic wastewater in Hanoi City which contain low-strength for COD (120-200 mg/L) but high in nitrogen content (10-40 mg/L). A lab scale anoxic-oxic system with a hollow fiber-Membrane Separation Bioreactor was operated at a flow rate of 5-10 L/h over a period of 150 days. The reactor was operated at different sludge recirculation rates. The MBR maintained relatively constant transmembrane pressure. During 150 days of reactor operation, treated water quality have COD of around 20 mg/L, NH4-N of less than 1 mg/L, NO3-N of less than 5 mg/L. The system shows good and stable efficiency for organic matter and nitrogen removal without adding an external carbon source and coagulants. The results based on the study indicated that the proposed process configuration has potential to treat the low-strength wastewater in Hanoi. / Mục tiêu của nghiên cứu là đề xuất được một công nghệ hiệu quả và phù hợp để xử lý nước thải sinh họat ở các đô thị của Việt nam, là loại nước thải được thu gom từ hệ thống thoát nước chung có nồng độ chất hữu cơ thấp (COD 120-200 mg/l) nhưng hàm lượng chất dinh dưỡng như Nitơ, Phốt pho khá cao (T-N: 10-40 mg/L). Chúng tôi đã nghiên cứu và vận hành chạy thử mô hình xử lý sinh học yếm khí - kỵ khí (AO) kết hợp với màng vi lọc ở quy mô mô hình phòng thí nghiệm (công suất 5-10 L/h) ở các chế độ công suất bùn tuần hoàn khác nhau. Kết quả xử lý trong thời gian 5 tháng vận hành mô hình cho thấy chất lượng nước thải sau xử lý có hàm lượng COD nhỏ hơn 20 mg/L, NH4-N nhỏ hơn 1 mg/L, NO3-N nhỏ hơn 5 mg/L. Hiệu suất xử lý chất hữu cơ và chất dinh dưỡng rất ổn định và hệ thống không phải sử dụng các nguồn bổ sung chất hữu cơ hay các hóa chất trợ lắng như các công nghệ đang áp dụng. Kết quả cho thấy công nghệ AO kết hợp màng vi lọc có khả năng áp dụng thực tế, phù hợp với những nơi có quỹ đất nhỏ, chất lượng nước sau xử lý rất cao có thể phục vụ cho mục đích tái sử dụng.

This research demonstrates the use of two novel methodologies to evaluate energy autarky status of wastewater treatment plants (WWTPs) in two steps. Step I (analysis 1 and 2) focuses on overall energy performance evaluation of a conventional activated sludge process (CAS) using a quantitative mass balance model. Step II involves development of a dynamic model that simulates a future wastewater resource recovery facility (WRRF). The step I (analysis 1) focused on small WWTPs with treatment capacities less than 5 MGD. The results revealed that a CAS process can achieve energy autarky or energy-positive status when old technology equipment is replaced with new, high efficiency equipment to save 10-12% energy; aeration energy is reduced by installing nitritation/anammox nitrogen removal process; and energy production is enhanced with the addition of FOG for co-digestion. Analysis 2 of step I focusing on large plant capacities (i.e., > 20 MGD) evaluated the effect of influent wastewater strength (IWWS), primary treatment COD removal efficiency (PT-COD), and proper design of combined heat and power (CHP) systems on the overall energy performance. The results showed that energy autarky is feasible when PT-COD is 60% for low IWWS, 40% or greater for medium IWWS, and 30% or greater for high IWWS. In step II analysis, a new and dynamic model was developed by integrating high rate algal pond (HRAP) and anaerobic digester (AD) systems. The model was calibrated using the experimental data from recent studies. The results showed that this system can achieve energy autarky when advanced solids separation and co-digestion systems are included. Solids separation efficiency was increased from 75 to 90% to reduce the winter effluent COD concentrations from HRAP (by 20%). Similarly, nitrogen effluent concentrations were reduced by increasing the solids retention time. Future studies should focus on techno-economic and environmental life cycle impact analysis of these novel process configurations.

Yes / Reverse Osmosis (RO) has already proved its worth as an efficient treatment method in chemical and environmental engineering applications. Various successful RO attempts for the rejection of organic and highly toxic pollutants from wastewater can be found in the literature over the last decade. Dimethylphenol is classified as a high-toxic organic compound found ubiquitously in wastewater. It poses a real threat to humans and the environment even at low concentration. In this paper, a model based framework was developed for the simulation and optimisation of RO process for the removal of dimethylphenol from wastewater. We incorporated our earlier developed and validated process model into the Species Conserving Genetic Algorithm (SCGA) based optimisation framework to optimise the design and operational parameters of the process. To provide a deeper insight of the process to the readers, the influences of membrane design parameters on dimethylphenol rejection, water recovery rate and the level of specific energy consumption of the process for two different sets of operating conditions are presented first which were achieved via simulation. The membrane parameters taken into consideration include membrane length, width and feed channel height. Finally, a multi-objective function is presented to optimise the membrane design parameters, dimethylphenol rejection and required energy consumption. Simulation results affirmed insignificant and significant impacts of membrane length and width on dimethylphenol rejection and specific energy consumption, respectively. However, these performance indicators are negatively influenced due to increasing the feed channel height. On the other hand, optimisation results generated an optimum removal of dimethylphenol at reduced specific energy consumption for a wide sets of inlet conditions. More importantly, the dimethylphenol rejection increased by around 2.51% to 98.72% compared to ordinary RO module measurements with a saving of around 20.6% of specific energy consumption.