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No description available.

By rethinking wastewater treatment plants (WWTPs) as resource recovery facilities, it is possible to de- velop the next generation of WWTPs. Moreover, it allows to accomplish environmental goals, such as reducing the CO2 footprint, and comply with increasing effluent standards regarding the concentration of nitrogen in a more sustainable way. This research study aims to analyse the possibility of recirculating carbon within WWTPs in form of volatile fatty acids (VFAs) produced by co-fermentation of primary sludge and food waste. The obtained fermentation liquid is utilised as carbon source to enhance the denitrification process in a post-anoxic denitrification plant setup. Two pilot scale fermentation reactors were semi-continuously operated, systematically varying only in pH. By controlling one reactor to pH 10, while the second reactor was operated without pH control, it was possible to assess the influence of the pH on the carbon recovery process. Despite the pH not being controlled in the second fermentation reactor, it adjusted itself to a stable pH around 5.4. The co-fer- mentation process was monitored by weekly analysis of the SCOD and total amount of VFAs (TVFA). While the alkaline conditions in the reactor operated at pH 10 allowed a higher hydrolysis of the sub- strate, the second reactor, operated without pH control, achieved a more distinct acidification, due to the lower pH. Consequently, the SCOD in the reactor operated without pH control contains a higher percentage of TVFA amounting to 64 % in comparison to the reactor operated at pH 10 with 40 % TVFA. Furthermore, the achieved degree of fermentation was assessed by calculating the net increase of TVFA per gram of VS, respectively VSS. A higher degree of fermentation was achieved without pH control, resulting in a higher VFA yield compared to the fermentation reactor operated at pH 10. Moreover, anal- ysis of the individual VFAs by gas chromatography showed distinct differences in the composition of the fermentation liquids. According to the findings, the reactor operated at pH 10 produced mainly acetic acid (61 %), followed by propionic acid (18 %) and n-butyric acid (14 %). In contrast, the fermentation reactor operated without pH control produced mainly n-caproic acid (47 %), followed by acetic acid (25 %) and n-butyric acid (16 %). Despite the similar fermentation substrate supplied to both reactors, the acidic conditions in the reactor operated without pH control allowed carboxylic acid chain elongation from acetic acid to n-caproic acid, resulting in the main difference of the fermentation liquids. The fermentation liquid of the two reactors was filtered, diluted to a concentration of 5 g COD/L and supplied as additional carbon source to enhance denitrification in two continuously operated pilot scale moving bed biofilm reactors (MBBR), applying a carbon-to-nitrogen ratio of 4.5. One of the denitrifica- tion MBBRs received the carbon recovered by fermentation at pH 10 as external carbon source, whereby the carbon source produced by fermentation without pH control was supplied to the other MBBR. The maximal achieved denitrification rate was quite similar for both MBBRs amounting to 3.25 g NO3- Neq/(m2·d) for the MBBR receiving the carbon source recovered by co-fermentation at pH 10 and 3.38 g NO3-Neq/(m2·d) for the MBBR receiving the VFA-mix obtained by co-fermentation without pH control. However, the MBBR provided with the carbon source recovered by co-fermentation under acidic conditions achieved a higher average denitrification rate of 2.5 g NO3-Neq/(m2·d), compared with the MBBR receiving carbon produced by co-fermentation at pH 10 (1.8 g NO3-Neq/(m2·d)). The lower efficiency of the MBBR supplied with additional carbon recovered by fermentation at pH 10 is caused by an accumulation of NO2-N during the denitrification process. This accumulation of NO2-N indicates suboptimal conditions, both due to the composition of the supplied carbon source and an overall higher pH during the denitrification process, which might supress facultative anaerobes, such as denitrifiers. Nevertheless, this study shows that both VFA-rich carbon sources obtained by co-fermentation of pri- mary sludge and food waste are suitable to enhance denitrification of municipal wastewater, with the carbon source recovered by fermentation without pH control achieving a higher denitrification effi- ciency. / Eine Neuinterpretation kommunaler Klärwerke als Rohstoff-Rückgewinnungsanlagen ermöglicht die Entwicklung der Kläranlagen der Zukunft. Umweltziele, wie die Reduktion des CO2-Fußabdrucks und die Einhaltung steigender Abwasserstandards im Hinblick auf die Stickstoffkonzentration können somit nachhaltiger erreicht werden. Diese Forschungsstudie zielt darauf ab, die Möglichkeit der Rückführung von Kohlenstoff in Kläranlagen in Form leichtflüchtiger Fettsäuren (engl. volatile fatty acids, VFAs) zu untersuchen. Diese VFAs werden durch Co-Fermentation von Primärschlamm und Lebensmittelabfäl- len erzeugt und als zusätzliche Kohlenstoffquelle einer nachgeschalteten Denitrifikation zugeführt, um die Prozesseffizienz zu steigern. Zur Erzeugung der VFAs wurden zwei Fermentationsreaktoren halbkontinuierlich im Pilotmaßstab be- trieben, welche systematisch im pH-Wert variierten. Der Einfluss des pH-Wertes auf den Kohlenstoff- rückgewinnungsprozess konnte beurteilt werden, indem ein Reaktor auf pH 10 geregelt wurde, während dieser im zweiten Reaktor nicht beeinflusst wurde. In diesem stellte sich aufgrund ablaufender Reakti- onen ein stabiler pH-Wert um 5,4 ein. Der Co-Fermentationsprozess wurde durch wöchentliche Analyse des gelösten chemischen Sauerstoffbedarfs (engl. soluble chemical oxygen demand, SCOD) und der Ge- samtmenge an VFAs (TVFA) überwacht. Während die alkalischen Bedingungen in dem bei pH 10 be- triebenen Reaktor eine höhere Hydrolyse des Substrats ermöglichten, erreichte der zweite Reaktor auf- grund des niedrigeren pH-Werts eine stärkere Versäuerung. Folglich enthält der SCOD in dem Reaktor, der ohne pH-Regelung betrieben wurde, mit 64 % einen höheren Anteil an TVFA im Vergleich zu dem bei pH 10 betriebenen Reaktor mit 40 % TVFA. Außerdem wurde der erreichte Fermentationsgrad durch Berechnung der Nettozunahme der TVFA pro Gramm flüchtige Feststoffe (VS) bzw. flüchtige suspendierte Feststoffe (VSS) erfasst. Ein höherer Fer- mentationsgrad konnte ohne pH-Regelung erzielt werden, welche eine höhere VFA-Ausbeute im Ver- gleich zur Fermentation bei pH 10 zeigt. Deutliche Unterschiede in der Zusammensetzung der gewon- nenen VFAs konnten durch Analyse mittels Gaschromatographie erfasst werden. Demzufolge entstand bei der Fermentation bei pH 10 hauptsächlich Essigsäure (61 %), gefolgt von Propionsäure (18 %) und n-Buttersäure (14 %). Im Gegensatz dazu, produzierte der Fermentationsreaktor ohne pH-Regelung überwiegend n-Capronsäure (47 %), gefolgt von Essigsäure (25 %) und n-Buttersäure (16 %). Trotz des gleichen Fermentationssubstrates, welches beiden Reaktoren zugeführt wurde, ermöglichen die sauren Bedingungen in dem Fermentationsreaktor ohne pH-Regelung, eine Verlängerung der Carbonsäureket- ten von Essigsäure zu n-Capronsäure. Nach Filtration der in verschiedenen Milieus gewonnenen Fermentationssubstrate und Verdünnung auf eine Konzentration von 5 g COD/L, wurden diese zwei im Pilotmaßstab kontinuierlich betriebenen Fließbett-Biofilmreaktoren (engl. Moving bed biofilm reactor, MBBR) als zusätzliche Kohlenstoffquelle zur Denitrifikation zugeführt. Über die gesamte Versuchsdauer wurden ein MBBR mit dem alkalisch gewonnenen und der Andere mit dem im sauren Milieu erzeugten VFA-Mix betrieben. Das Kohlenstoff- Stickstoff-Verhältnis (C/N Ratio) lag dabei bei 4,5. Beide MBBRs wiesen eine vergleichbare maximale Denitrifikationsrate von 3,25 g NO3-Neq/(m2·d) (VFAs pH 10) und 3,38 g NO3-Neq/(m2·d) (VFAs pH un- geregelt) auf. Der MBBR, welcher die im sauren Milieu rückgewonnene Kohlenstoffquelle erhielt, er- reichte im Durchschnitt eine höhere Denitrifikationsrate von 2,5 g NO3-Neq/(m2·d) als der MBBR, der den bei pH 10 gewonnenen VFA-Mix erhielt (1,8 g NO3-Neq/(m2·d)). Die im Vergleich geringere Effizi- enz der alkalisch rückgewonnenen Kohlenstoffquelle wird durch eine NO2-N-Anreicherung während der Denitrifikation verursacht, welche suboptimale Bedingungen während des Prozesses indiziert. Dies ist sowohl auf die Zusammensetzung der zugeführten Kohlenstoffquelle, als auch auf einen insgesamt hö- heren pH-Wert während des Reduktionsprozesses zurückzuführen, der fakultative Anaerobier, wie bspw. Denitrifikanten, unterdrücken kann. Dessen ungeachtet zeigt diese Studie, dass beide durch Co- Fermentation von Primärschlamm und Lebensmittelabfällen gewonnenen VFA-reichen Kohlenstoff- quellen zur Verbesserung der Denitrifikation kommunalen Abwassers geeignet sind, wobei die durch Fermentation ohne pH-Regelung erzeugte Kohlenstoffquelle eine höhere Effizienz aufweist. / Det är möjligt att utveckla den nya generationen av avloppsreningsverk genom att ompröva avloppsreningsverk som resursanläggning. Därtill möjliggör det att uppnå miljömål som att minska koldioxidavtrycket och följa ökande utsläppskrav, t.ex. för kvävekoncentration, på ett mer hållbart sätt. Denna forskningsstudie syftar till att analysera möjligheten att återcirkulera kol inom reningsverket i form av lättflyktiga fettsyror (engl. volatile fatty acids, VFAs), producerades genom samfermentering av primärslam och matavfall. Det erhållna fermenteringssubstratet används som extern kolkälla för att förbättra processeffektiviteten i en efterdenitrifikationsanläggning. Två pilotskaliga fermenteringsreaktorer drevs i semikontinuerligt driftläge med endast en skillnad i pH. Det var möjligt att utvärdera pH-påverkan på kolåtervinningsprocessen genom att kontrollera pH- värdet i en reaktor till pH 10, medan den andra reaktorn drevs utan pH-kontroll. På grund av reaktionerna som fortlöpte, justerade sig den icke-kontrollerade reaktorn själv till ett stabilt pH runt 5,4. Samfermenteringsprocessen övervakades genom veckoanalys av kemisk syreförbrukning i filtrerade prover (engl. soluble chemical oxygen demand, SCOD) och total mängd av VFAs (TVFA). Medan den alkaliska miljö i den första reaktorn gynnade en högre hydrolys av substratet, uppnådde den andra reaktorn en mer tydlig surgöring på grund av det lägre pH-värdet. Följaktligen innehåller SCOD i reaktorn som drivs utan pH-kontroll en större andel TVFA – 64 % av SCOD - jämfört med reaktorn som drivs vid pH 10, där TVFA utgör 40 % av SCOD. Vidare analyserades den uppnådda fermenteringsgraden genom att beräkna nettoökningen av TVFA per gram VS, respektive VSS. En högre jäsningsgrad uppnåddes i sur miljö, vilket resulterade i en högre VFA-produktion jämfört med fermenteringsreaktorn som drevs vid pH 10. Därtill visade analys med gaskromtografi av de individuella VFA tydliga skillnader i sammansättning av substraten. Enligt rönen producerade reaktorn vid pH 10 mestadels ättiksyra (61 %) följt av propionsyra (18 %) och n-smörsyra (14 %). Däremot producerade fermenteringsreaktorn utan pH-kontroll mestadels n-kapronsyra (47 %) följt av ättiksyra (25 %) och n-smörsyra (16 %). Detta visar att trots att samma fermentationssubstrat användes för båda reaktorerna möjliggör den sura miljön i reaktorn utan pH-kontroll karboxylkedjeförlängningen från ättiksyra till n-kapronsyra. Fermentationssubstraten av de två reaktorerna filtrerades, utspäddes till en koncentration av 5 g COD/L och tillfördes som extern kolkälla, med ett kol/kväve-förhållande på 4,5, för att förbättra denitrifikationen i två kontinuerliga drivna biofilmreaktorer med rörliga bärare (engl. moving bed biofilm reactor, MBBR). En MBBR erhöll under hela experimentets gång den kolkälla som bildats under alkaliska förhållanden och den andra MBBR:en erhöll motsvarande kolkälla som bildats i den sura miljön i fermenteringsreaktorn utan pH-kontroll. Den maximala uppnådda denitrifikationskapaciteten var ganska likartad för båda MBBR: 3,25 g NO3-Neq/(m2·d) för den MBBR som opererades med den alkaliska erhållen kolkällan och 3,38 g NO3-Neq/(m2·d) för MBBR som erhöll den utspädda fermenteringsvätskan bildad utan pH-kontroll. Emellertid uppnådde den MBBR som erhöll kolkällan bildad i sura miljön en högre genomsnittlig denitrifikationskapacitet på 2.5 g NO3-Neq/(m2·d) jämfört med MBBR som fick kolkällan producerad genom fermentering vid pH 10 (1.8 g NO3-Neq/(m2·d)). Den lägre effektiviteten i den MBBR som fick den alkaliskt erhållna kolkällan orsakas av en ansamling av NO2-N under denitrifikationsprocessen, vilket indikerar suboptimala förhållanden. Detta beror både på sammansättningen av den tillförda kolkällan och ett högre totalt pH-värde under reduktionsprocessen, vilket kan hämma fakultativa anaerober såsom denitrifierare. Trots det visar denna forskningsstudie att båda de VFA-rika kolkällorna erhållna genom samfermentering av primärslam och matavfall är lämpliga för att förbättra denitrifikationen av kommunalt avloppsvatten, varvid kolkällan som produceras genom fermentering utan pH-kontroll uppnår en högre denitrifikationseffektivitet.

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The advent of industrial, fertilizer-intensive agriculture during the 20th century has promoted export of anthropogenic nutrients, spurring degradation of ecosystem biodiversity and water quality. Exported nitrogen and phosphorus are recognized drivers of this deterioration, and require management. In the mid-1990s, denitrifying bioreactors (DNBRs), a subsurface, edge-of-field best management practice (BMP) that intercepts and treats agricultural drainage by supporting nitrate-attenuating denitrification with a saturated, carbon-filled substrate, were developed. Since then, their utility has expanded, and recent studies have unearthed biochar's capability to stimulate simultaneous nitrate (NO3--N) and phosphate (PO43--P) removal in DNBRs. This study investigated biochar's potential as an amendment to the traditional woodchip media by conducting nine, five-day trials on twelve laboratory-scale, horizontal flow-through DNBR columns. Three media types were tested: woodchips (W), 90% woodchips and 10% biochar (B10), and 70% woodchips and 30% biochar (B30). Simulated agricultural drainage with four unique concentration combinations of 16.1 and 4.5 mg L-1 NO3--N and 1.9 and 0.6 mg L-1 PO43--P was delivered at hydraulic retention times (HRTs) of 3, 6, and 12 h. Mean NO3--N removal efficiencies ranged from 16.9%-93.7%, and media type was insignificant at low influent NO3--N concentrations, but B30 was the most effective at high influent NO3--N concentrations. Mean PO43--P removal efficiencies ranged from -122.0%-74.9%, with B10 and B30 significantly worse than W at removing PO43--P. These findings corroborate previous work indicating boosted NO3--N removal with biochar, but contradict studies upholding PO43--P-removing capabilities. / Master of Science

Removal of nitrogen elements in culture water is one of the major concerns in recirculating aquaculture system (RAS). Maintaining a low concentration of nitrogen compounds is essential for a good quality of aquaculture production. Due to fish is very sensitive to the toxic ammonium/ammonia, nitrification biofiltration tank is often an integrate part of filtration in RAS to remove ammonium via nitrification. However, nitrate accumulation via nitrification in RAS is often observed during the operation, which is usually solved by replacing with the fresh water into the system. With the concern of water consumption, bio-electrochemical system (BES) is introduced in this study to realize simultaneous nitrate removal for the system while generating the electricity through electron transferring. A microbial fuel cell (MFC) with an anion exchange membrane (AEM) was constructed. The removal of nitrate from aquaculture water generated from RAS was achieved by nitrate migration across the AEM and heterotrophic denitrification in the anode chamber. To further investigate the potential application of BES in RAS, the cathode chamber was incubated with biofilm to do the nitrification while the denitrification processing in the anode chamber. The study gave a total inorganic nitrogen removal efficiency of 38.72% ± 4.99, and a COD removal of 86.09% ± 9.83. The average daily electricity generation was 67.98 A m-3 ± 13.91, and nitrate-nitrogen concentration remained at 21.02 ± 2.62 mg L-1 throughout the experiment. These results of treating aquaculture water indicate that BES has a potential to install within RAS for enhanced nitrogen removal. / MS

Increases in reactive nitrogen from human actions have led to negative impacts on surface water (SW) and groundwater (GW) quality, and it is important to better understand denitrification processes in aquatic systems. The hyporheic zone has unique biogeochemical conditions, and is known to attenuate contaminants originating from SW and traveling through the hyporheic zone, together with necessary reactants. However, the ability of the hyporheic zone to attenuate contaminants from deeper upwelling GW plumes as they exit to SW is less understood. I used MODFLOW and SEAM3D to simulate hyporheic flow cells induced by riverbed dunes and upwelling GW together with mixing dependent denitrification of an upwelling nitrate (NO3-) plume. My basecase model scenario entailed dissolved organic carbon (DOC) and dissolved oxygen (DO) advecting from SW and DO and NO3- advecting from GW, which is typical of water in agricultural land uses. I conducted a sensitivity analysis to determine controls on mixing dependent denitrification. Mixing dependent denitrification increased with increasing hydraulic conductivity, decreasing lower bottom flux, as well as increasing DOC in SW and NO3- in GW. Non-mixing dependent denitrification also occurred when there was SW NO3-, and I found its magnitude was much greater than mixing dependent denitrification. Nevertheless, potential for hyporheic zones to attenuate upwelling NO3- plumes seems to be substantial, though highly variable depending on biogeochemical reaction rates as well as geomorphic, hydraulic and biogeochemical conditions. Stream and river restoration efforts may be able to increase both mixing and non-mixing dependent reactions by increasing hyporheic zone residence times. / Master of Science

Increased reactive nitrogen from human activities negatively affects surface water (SW) quality. The hyporheic zone, where SW and groundwater interact, possesses unique biogeochemical conditions that can attenuate contaminants (e.g., denitrification), including mixing-dependent reactions that require components from both water sources. Previous research has explored mixing-dependent denitrification in the hyporheic zone but did not address the effects of varying SW depth as would occur from storms, tides, dam operation, and varying seasons. We simulated steady and unsteady hyporheic flow and transport through a riverbed dune using MODFLOW and SEAM3D, and varied SW depth, degree of sediment heterogeneity, amplitude and frequency of sinusoidal fluctuations, among others to determine these effects. We found that increasing steady state surface water depth from 0.1 to 1.0 m increased non-mixing dependent aerobic respiration by 270% and mixing-dependent denitrification by 78% in homogeneous sediment. Heterogeneous hydraulic conductivity fields yielded similar results, with increases in consumption due to variation in correlation length and variance of less than 5%. Daily SW fluctuation, including variation of amplitude, period, and sinusoidal versus instantaneous changes had significantly less impact than longer-term trends in SW depth. There is potential for the hyporheic zone to attenuate NO3- in upwelling groundwater plumes. Restoration efforts may be able to maximize the potential for mixing-dependent reactions in the hyporheic zone by increasing residence times. / Master of Science / Increased nitrogen in runoff from human activities negatively affects surface water quality. The hyporheic zone is where surface water and groundwater interact, and the mixing between the waters can help to this nitrogen to undergo reaction (denitrification), potentially stopping the contaminant from spreading. Previous research has explored this idea, but has not addressed the impact of varying surface water depth, as would realistically occur due to storms, tides, dam operation, and varying seasons. We simulated both constant and fluctuating surface water conditions on a riverbed dune to see the effects on hyporheic flow and denitrification. Test variables included the surface water depth, the degree of sediment heterogeneity, the amplitude and frequency of surface water fluctuations. We found that increasing the steady-state surface water depth had the most dramatic increase on the amount of reaction undergone. This trend was also seen in heterogeneous sediment. Any daily-scale surface water fluctuations, including runs that varied the amplitude, period, and sinusoidal vs instantaneous changes in surface water depth, had significantly less impact than longer-term trends in surface water depth.

The Integrated Film Activated Sludge Process (IFAS) was developed to reduce the cost of additional facilities required to complete year round nitrification in the design of new or retrofit wastewater treatment plants. The purpose of this project was to develop a computer-based mechanistic model, called IFAS, which can be used as a tool by scientists and engineers to optimize their designs and to troubleshoot a full-scale treatment plant. The program also can be employed to assist researchers conducting their studies of IFAS wastewater treatment processes. IFAS enables the steady-state simulation of nitrification-denitrification processes as well as carbonaceous removal in systems utilizing integrated media, but this current version supports only sponge type media. The IFAS program was developed by incorporating empirical equations for integrated biofilm carbonaceous uptake and nitrification developed by Sen and Randall (1995) into the general activated sludge model, developed by the International Association on Water Quality (IAWQ, previously known as IAWRC), plus the biological phosphorus removal model of Wentzel et al (1989). The calibration and evaluation of the IFAS model was performed using existing data from both an IFAS system and a conventional activated sludge bench-scale plant operated over a wide range of Aerobic Mean Cell Residence Times (Aerobic MCRT's). The model developed provides a good fit and a reasonable prediction of the experimental data for both the IFAS and the conventional pilot-scale systems. The phosphorus removal component of the model has not yet been calibrated because of insufficient data and the lack of adequately defined parameters. / Master of Science

Partial denitrification/anammox (PdNA) is a biological nitrogen removal technology with significant carbon and aeration savings when compared with conventional nitrification/denitrification. Yet despite these benefits, the use of PdNA in mainstream wastewater treatment remains limited. One of the main barriers to implementation of anammox-based technologies is the slow growth rate of anammox (AMX), which results in a long startup time. To accelerate startup, the typical approach to commissioning AMX-based processes, specifically used for sidestream partial nitritation/AMX, is with biomass augmentation, which is practically unrealistic for full-scale mainstream applications. Thus, this study evaluated startup strategies for mainstream PdNA without AMX inoculation in moving bed biofilm reactors (MBBRs) with two simultaneous experiments. In one experiment, an MBBR was started using IFAS carriers with a preliminary biofilm and no external carbon dosing or AMX biomass inoculation. The feed was controlled to 20°C and included mainstream conditions of nitrite and ammonia controlled to the stoichiometric requirements for AMX growth. After only 84 days of operation, AMX activity was confirmed in the reactor with evidence of activity a few weeks before testing. In the second experiment, four reactors were started with either virgin carriers or integrated fixed-film activated sludge (IFAS) carriers with a preliminary biofilm of heterotrophs and nitrifiers. The reactors were fed mainstream levels of ammonia and nitrate with a temperature control target of 20°C and one reactor of each carrier type was dosed with carbon in the form of either glycerol or methanol. Carbon dosing was based on a feedback proportional-integrative-derivative (PID) control loop with a nitrate residual of 1-1.5 mgNO3-N/L. Of the four reactors, the preliminary biofilm carrier reactor dosed with glycerol achieved AMX activity first after 224 days of operation, but it was determined this was likely limited by synthetic feeding for the first 184 days. These results, along with other recent PdNA work, suggest that growth of AMX on biofilm carriers can be established in mainstream conditions in 50-100 days, depending on media selection and carbon source. Ultimately, this research will help utilities understand methods for starting up mainstream PdNA MBBRs from scratch and make this technology more accessible. / Master of Science / Intensification is the practice by which operational changes and new technologies are employed to reduce economic, resource, energy, and space requirements of wastewater treatment plants. One area of increasing focus involves the use of anaerobic ammonia oxidizing bacteria, or anammox (AMX), to reduce the aeration and carbon dosing needs for treating wastewater. One of the main barriers to implementation of AMX-based technologies is the slow growth rate of AMX, which results in a long startup time. To accelerate startup, the typical approach to commissioning AMX-based processes, specifically used for sidestream partial-nitritation/AMX, is with augmentation of biomass, which is practically unrealistic for full-scale mainstream applications. Thus, this study evaluated startup strategies for mainstream moving bed biofilm reactors (MBBRs) without AMX biomass inoculation in two simultaneous experiments in an AMX MBBR and a partial denitrification/AMX (PdNA) MBBR. In one experiment, idealized stoichiometric conditions for AMX growth were provided to a mainstream MBBR started with carriers from an aerobic integrated fixed-film activated sludge (IFAS) process to determine how fast AMX could potentially grow. In another experiment, different carrier types, virgin or preliminary biofilm carriers from an IFAS process, and different carbon sources, methanol and glycerol, were tested to determine the best methods for encouraging AMX attachment and growth in a PdNA process. These results, along with other recent PdNA work, suggest that growth of AMX on biofilm carriers can be established in mainstream conditions within 50-100 days, depending on media selection and carbon source. Ultimately, this research will help utilities understand methods for starting up mainstream PdNA MBBRs from scratch and make this technology more accessible.