| 1. |
- Baresel, Christian, et al.
(författare)
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Direct GHG emissions from a pilot scale MBR-process treating municipal wastewater
- 2022
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Ingår i: Advances in Climate Change Research. - : Elsevier BV. - 1674-9278 .- 2524-1761. ; 13:1, s. 138-145
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate direct greenhouse gas emissions from Membrane Biological Reactor (MBR), measurements of nitrous oxide (N2O) and methane (CH4) were made at a pilot-scale MBR treating municipal wastewater Measurements were conducted during two campaigns with some changes in processes, i.e. introducing a pre-aeration tank in the second measurement, different distributions of aeration in the treatment line, not the same wastewater inflow rate, two types of ultrafiltration membrane. It was found that about 0.004% and 0.07% of the total ammonium loads were emitted as N2O, CH4 emissions were 0.026% and 0.12% of incoming TOC (0.008% and 0.04% of incoming COD) in 2014 and 2018. The obtained N2O emission values were relatively low.The study suggested that a high aeration at the beginning of the treatment line may result in significantly high emissions of both N2O and CH4. A significant change in aeration in the membrane ultrafiltration tank did not have the same impact. The MBR process is known for high quality effluent but have been questioned due to its higher carbon footprint due to energy consumption. This study gave a reference case about direct GHG emissions from MBR process and provide information for the further evaluation of MBR processes.
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| 2. |
- Baresel, Christian, et al.
(författare)
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Lustgasutsläpp från behandlingen av rejektvatten vid Slottshagens reningsverk i Norrköping
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vid Slottshagen reningsverk gjordes en av de första karteringarna av lustgasemissioner (N2O) från rejektvattenreningen. De första mätningarna genomfördes 2012 och visade på relativt höga utsläpp av lustgas med i genomsnitt 10 % av inkommande kväve, men periodvis väsentlig högre emissioner än så. Därmed kunde det konstateras att processen trots en effektiv kväverening bidrog med en signifikant miljöpåverkan. För att minska den negativa miljöpåverkan genom höga utsläpp av lustgas, som är en 298 gånger starkare växthusgas än koldioxid, utarbetade IVL olika åtgärdsstrategier till Nodra AB som skulle resultera i minskade emissioner både på kort och lång sikt. Som snabb åtgärd rekommenderades en anpassning av etanoldosering för att minska utsläppen. En uppföljningsmätning visade att lustgasemissionerna hade minskats till i genomsnitt 5 - 6 % av den genomsnittliga kvävebelastningen. Den långsiktiga rekommendationen till Nodra AB var att ställa om reningsprocessen från Satsvis Biologisk Rening (SBR) med konventionell nitrifikation och denitrifikation till 1-stegs deammonifikation vilket innefattar de biologiska processerna nitritation och anammox. Efter avslutad ombyggnad 2017 gjordes en ny mätning 2018 som tyder på signifikant lägre lustgasutsläpp i deammonifikationsprocessen (<1% av kvävebelastningen). En ytterligare optimering av processen med fokus på pH-styrningen som genomfördes i samarbete med Mälardalens högskola (MDH) och Purac AB resulterade i ännu lägre utsläpp motsvarande <0,2 % av kvävebelastningen. Även om det i det här fallet föreslogs en viss styrningsändring som kortsiktig åtgärd och ombyggnad till en deammonifikation (nitritation/anammox) med MBBR (Moving Bed Biofilm Reactor) som långsiktig åtgärd så kan det finnas fler åtgärdsstrategier än dessa för att minska lustgasavgång. Det viktigaste momentet i en framgångsrik reducering av växthusgasutsläpp är kunskapen om situationen och viljan till förändringar. Nodra AB har varit drivande i dessa frågor och trots överraskande höga lusgasutsläpp som upptäcktes vid karteringen, har de kontinuerligt jobbat med att reducera dessa med hjälp av extern expertis.
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| 3. |
- Baresel, Christian, et al.
(författare)
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Ny teknik för mätning av växthusgaser vid avloppsreningsverk : Vid behandling av kallt avloppsvatten och vid avsaknad av kväverening
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Utsläpp av lustgas (N2O) utgör en betydande andel av klimatpåverkan från avloppsreningsverk (ARV). Medan de genomsnittliga utsläppen av lustgas från avloppsreningsverk med kväverening bedöms generellt ligga på ca 1,6 % av inkommande kväve förväntas inga lustgasemissioner i avloppsreningsverk utan kväverenande aktivitet. Detta eftersom lustgas bildas via processer som alla ingår i den biologiska kväveavskiljningen i avloppsvattenreningen. Dock kan det förekomma spontan och okontrollerad nitrifikation som kan leda till mycket höga lustgasutsläpp. Relativt ringa lustgasemissioner kan vara betydande för avloppsreningsverkens klimatavtryck eftersom lustgas är en mycket kraftig växthusgas, ca 273 gånger kraftigare än koldioxid. Trots den ökande kunskapen om lustgasutsläppens betydelse i avloppsreningsverkens klimatarbete utförs det fortfarande relativt få mätningar av lustgasutsläpp vid svenska ARV. Detta gör att det finns flera kunskapsluckor om och förståelse för lustgasutsläpp för att aktivt kunna vidta åtgärder för att minska dessa utsläpp. En anledning till att få mätningar genomförs är att det i dag inte finns krav på sådana mätningar och inte heller enkla metoder för lustgasmätning tillgängliga för VA-aktörer. Projektet har därför syftat till att öka kunskapen om lustgasutsläpp från avloppsrening i kallt klimat, med eller utan kontrollerad nitrifikation. Kallt klimat refererar till avloppsvatten som har minimitemperaturer ner till 4–5 grader. I samarbete med teknikleverantörer har dessutom nya lustgassensorer, anpassat för mätningar vid avloppsreningsverk, testats. För att kunna genomföra projektet med tilldelade medel och för att åstadkomma synergieffekter kopplades projektet till ett pågående pilotprojekt för kväverening i kall klimat vid Fillan avloppsreningsverk i Sundsvall, som även SVU medverkar i. Lustgasmätningar vid Fillan ARV som representerar en biologisk reningsprocess i kallt klimat utan kväverening är som förväntat låga. De uppmätta emissionerna uppgick till ca 0,17 % N2O-N/TN trots att en spontan och okontrollerad nitrifikation inte kunde observeras. Även om lustgasemissioner är låga så visar emissionsberäkningar att lustgasavgången ändå inte är försumbar och utgör ett avsevärt bidrag till klimatpåverkan. Lustgasmätningar i pilotanläggningen som representerar biologiska reningsprocesser med kväverening i kallt klimat indikerar att emissionerna kan antas vara i samma storleksordning eller högre som vid avloppsreningsverk med kväverening som inte har ett kallt inkommande avloppsvatten som regel. Ingen signifikant skillnad i lustgasemissioner kunde observeras mellan pilotens två linjer, varav den ena linjen värmdes med +4 °C mot referenslinjen. Utvärdering av de två nya sensorer från Unisense och Senseair har visat en mycket bra överensstämmelse mellan kalibrerade sensordata och referensmätningarna. Båda sensorer har därför en potential att användas för en kontinuerlig mätning av lustgas i gasfas ifall en kommersiell produktutveckling sker. Resultaten från kalibreringen indikerar dock vikten av en regelbunden kalibrering av sensorerna för att säkerställa korrekta mätningar, så som för sensorer i allmänhet. Kalibreringsmetoden som tillämpades inom projektet bedöms som rimlig men är inte den mest robusta eller noggranna metoden för en fullskaleimplementering.Även utifrån andra implementeringsaspekter framstår de två testade sensorerna som ett tänkbart alternativ till andra mättekniker. Dock är dessa sensorer ännu inte kommersiellt tillgängliga och kompletterande långtidstester av sensorerna bör genomföras för en utvärdering som även kan ta hänsyn till aspekter relaterat till mätstabilitet och underhållsbehov vid långtidsdrift. En annan aspekt som projektet vill lyfta fram är vikten av att korrekta luftflödesmätningar utförs samtidigt som haltmätningarna. Endast en bra haltmätning i kombination med en korrekt luftflödesmätning vid mätpunkten kan ge ett korrekt underlag för emissionsberäkningar. Tyvärr kan det konstateras att enkla, robusta och ekonomiskt överkomliga sensorer för kontinuerlig luftflödesmätning inte finns idag och att det krävs en teknikutveckling även inom detta område.
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| 4. |
- Ekstrand, Eva-Maria, 1985-, et al.
(författare)
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Identifying targets for increased biogasproduction through chemical and organicmatter characterization of digestate from full‑scale biogas plants : what remains and why?
- 2022
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Ingår i: Biotechnology for Biofuels and Bioproducts. - London, United Kingdom : BioMed Central. - 2731-3654. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study examines the destiny of macromolecules in different full-scale biogas processes. From previousstudies it is clear that the residual organic matter in outgoing digestates can have significant biogas potential,but the factors dictating the size and composition of this residual fraction and how they correlate with the residualmethane potential (RMP) are not fully understood. The aim of this study was to generate additional knowledge of thecomposition of residual digestate fractions and to understand how they correlate with various operational and chemicalparameters. The organic composition of both the substrates and digestates from nine biogas plants operating onfood waste, sewage sludge, or agricultural waste was characterized and the residual organic fractions were linked tosubstrate type, trace metal content, ammonia concentration, operational parameters, RMP, and enzyme activity.Results: Carbohydrates represented the largest fraction of the total VS (32–68%) in most substrates. However, inthe digestates protein was instead the most abundant residual macromolecule in almost all plants (3–21 g/kg). Thedegradation efficiency of proteins generally lower (28–79%) compared to carbohydrates (67–94%) and fats (86–91%).High residual protein content was coupled to recalcitrant protein fractions and microbial biomass, either from thesubstrate or formed in the degradation process. Co-digesting sewage sludge with fat increased the protein degradationefficiency with 18%, possibly through a priming mechanism where addition of easily degradable substrates alsotriggers the degradation of more complex fractions. In this study, high residual methane production (> 140 L CH4/kgVS) was firstly coupled to operation at unstable process conditions caused mainly by ammonia inhibition (0.74 mgNH3-N/kg) and/or trace element deficiency and, secondly, to short hydraulic retention time (HRT) (55 days) relative tothe slow digestion of agricultural waste and manure.Conclusions: Operation at unstable conditions was one reason for the high residual macromolecule content andhigh RMP. The outgoing protein content was relatively high in all digesters and improving the degradation of proteinsrepresents one important way to increase the VS reduction and methane production in biogas plants. Post-treatment
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| 5. |
- Kanders, Linda, 1979-, et al.
(författare)
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Full-scale comparison of N2O emissions from SBR N/DN operation versus one-stage deammonification MBBR treating reject water : - and optimization with pHset-point
- 2019
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 79:8, s. 1616-1625
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Tidskriftsartikel (refereegranskat)abstract
- To be able to fulfill the Paris agreement regarding anthropogenic greenhouse gases, all potential 12 emissions must be mitigated. Wastewater treatment plants should aim to eliminate emissions of the 13 most potent greenhouse gas, nitrous oxide. In this study, these emissions were measured at a full-scale 14 reject water treatment tank during two different operation modes: nitrification/denitrification (N/DN) 15 operating as a sequencing batch reactor (SBR), and deammonification (nitritation/anammox) as a moving 16 bed biofilm reactor (MBBR). Nitrous oxide was measured both in the water phase and in the off-gas. The 17 treatment process emitted significantly less nitrous oxide in deammonification mode 0.14-0.7 %, 18 compared to 10 % of Total Nitrogen in N/DN mode. The decrease can be linked to the change feeding 19 strategy, concentration in nitrite, load of ammonia oxidized, shorter aeration time, no ethanol dosage 20 and the introduction of biofilm. Further, evaluation was done how the operational pH set point 21 influenced the emissions in deammonification mode. Lower concentrations of nitrous oxide was 22 measured in water phase at higher pH (7.5-7.6) than at lower pH (6.6-7.1). This is believed to be mainly 23 because of the lower aeration ratio and increased complete denitrification at the higher pH set point.
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| 6. |
- Kanders, Linda, 1979-, et al.
(författare)
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Impact of seeding on the start-up of one-stage deammonification MBBRs
- 2014
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Ingår i: Environmental technology. - : Taylor & Francis. - 0959-3330 .- 1479-487X. ; 35:22, s. 2767-2773
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Tidskriftsartikel (refereegranskat)abstract
- Treating nitrogen-rich reject water from anaerobically digested sludge with deammonification has become a very beneficial side stream process. One common technique is the one-stage moving bed bioreactors (MBBRs), which in comparison with the other deammonification techniques can be started up without seeding anammox bacteria. This study investigated the impact of biofilm seeding on the start-up of one-stage deammonification MBBRs. Two lab-scale reactors were run in parallel with partial nitritation for 56 days until 11% of the carrier area in one reactor was replaced with fully developed deammonification biofilm to work as the seeding material. The seeded reactor started nitrogen reduction immediately up to a plateau of 1.3gNm−2 d−1; after another 54 days on day 110, the reduction significantly increased. At the same time, the non-seeded reactor also started to reduce nitrogen due to deammonification. The development was followed with both nitrogen analyses and fluorescence in situ hybridization analyses. On day 134, the biofilm in both reactors contained >90% anammox bacteria and reached maximum nitrogen removal rates of 7.5 and 5.6gNm−2 d−1 in the seeded and non-seeded reactor, respectively. Over 80% of the inorganic nitrogen was reduced. In conclusion, the seeding did not contribute to a shorter start-up time or the achieved anammox enrichment, although it did contribute to a partial, immediate nitrogen reduction. The boundary conditions are the most important factors for a successful start-up in a deammonification MBBR system.
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| 7. |
- Kanders, Linda, et al.
(författare)
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Rapid start-up of one-stage deammonification MBBR without addition of external inoculum
- 2016
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Ingår i: WATER SCIENCE AND TECHNOLOGY. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 74:11, s. 2541-2550
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the anammox process has emerged as a useful method for robust and efficient nitrogen removal in wastewater treatment plants (WWTPs). This paper evaluates a one-stage deammonification (nitritation and anammox) start-up using carrier material without using anammox inoculum. A continuous laboratory-scale process was followed by full-scale operation with reject water from the digesters at Bekkelaget WWTP in Oslo, Norway. A third laboratory reactor was run in operational mode to verify the suitability of reject water from thermophilic digestion for the deammonification process. The two start-ups presented were run with indigenous bacterial populations, intermittent aeration and dilution, to favour growth of the anammox bacterial branches. Evaluation was done by chemical and fluorescence in situ hybridization analyses. The results demonstrate that anammox culture can be set up in a one-stage process only using indigenous anammox bacteria and that a full-scale start-up process can be completed in less than 120 days.
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| 8. |
- Kanders, Linda, et al.
(författare)
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Sinks and sources of anammox bacteria in a wastewater treatment plant - screening with qPCR
- 2018
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 78:2, s. 441-451
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Tidskriftsartikel (refereegranskat)abstract
- The deammonification process, which includes nitritation and anammox bacteria, is an energyefficient nitrogen removal process. Starting up an anammox process in a wastewater treatment plant (WWTP) is still widely believed to require external seeding of anammox bacteria. To demonstrate the principle of a non-seeded anammox start-up, anammox bacteria in potential sources must be quantified. In this study, seven digesters, their substrates and reject water were sampled and quantitative polymerase chain reaction (qPCR) was used to quantify both total and viable anammox bacteria. The results show that mesophilic digesters fed with nitrifying sludge (with high sludge ages) can be classified as a reliable source of anammox bacteria. Sludge hygienization and dewatering of digestate reduce the amount of anammox bacteria by one to two orders of magnitude and can be considered as a sink. The sampled reject waters contained on average >4.0 × 104 copies mL1 and the majority of these cells (>87%) were viable cells. Furthermore, plants with side-stream anammox treatment appear to have higher overall quantities of anammox bacteria than those without such treatment. The present study contributes to the development of sustainable strategies for both startup of anammox reactors and the possibility of improving microbial management in WWTPs.
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| 9. |
- Kanders, Linda, 1979-
(författare)
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Start-up and operational strategies for deammonification plants : - a study with one-stage moving bed biofilm reactors treating reject water
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To limit eutrophication, wastewater treatment plants use biological methods to convert degraded nitrogen to nitrogen gas. Deammonification, or partial nitritation in combination with anammox, has been shown to be an energy efficient process. This process is currently implemented in approximately 150 full-scale plants, and mainly on reject waters, the liquid fraction after dewatering of anaerobic digestion at municipal wastewater treatment plants. Implementation has been impeded by the slow growth of anammox bacteria, and 99% of the full-scale plants using the process have been using different methods to inoculate the process with anammox bacteria from elsewhere. Separate reject water installations, however, have shown high nitrous oxide emissions, which could increase the total carbon footprint.The objective of this thesis was to develop and validate a start-up concept using the moving bed biofilm reactor (MBBR) technique applied to reject water, and to investigate how the operational strategies could be optimized to limit potential nitrous oxide emissions. The results show that a one-stage deammonification process based on the MBBR technology with indigenous anammox bacteria originating from the reject water can be set up within a applicable time frame (<100 days). This was validated in two laboratory reactors and in two full-scale studies. Reject water originating from both mesophilic and thermophilic digested sludge was used. Anammox growth and nitrogen reduction were detected with fluorescence in situ hybridization (FISH) and chemical analysis, respectively. The start-up time was 72 days in the laboratory and 120 days in full-scale. In laboratory scale, there was no improvement in start-up time when adding external anammox inoculum. Results from a screening study of seven reject waters and their content of anammox bacteria using qPCR indicated the presence of 104–105 genome units anammox per mL in reject water, which could be sufficient for starting up deammonification plants within an applicable time frame.A final case study shows the potential of decreasing nitrous oxide emissions when a full-scale plant treating reject water was modified from nitrification/denitrification using a Sequencing Batch Reactor (SBR) to a deammonification process using the MBBR technique. The nitrous oxide emissions decreased from 10% to 0.1–0.7% of total nitrogen load with the change of operation mode. Further optimization by pH set point led to lower emission values. This effect is thought to be linked to the lower aeration ratio and increase in complete denitrification of dissolved nitrous oxide at higher pH.
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| 10. |
- Kanders, Linda, 1979-
(författare)
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Swedish Experience of the Deammonification Process in a Biofilm System
- 2011
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Ingår i: Swedish experience with deammonification process in biofilm system. ; , s. 1333-1345
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Konferensbidrag (refereegranskat)abstract
- Based on results from many years of pilot plant experiments a one-stage deammonificationprocess for treatment of supernatant from dewatering of digested sludge has been applied in afull scale at the Himmerfjärden wastewater treatment plant in the Stockholm region. The plantwas designed for nitrogen load of 480 kg d-1 and is based on the Moving Bed Biofilm Reactor(MBBR), with about 32% of its volume filled with suspended carriers (K1H, Kaldnes®). Anouter biofilm layer performs nitritation while an inner layer the anammox reaction.Experience gained from more than 2 years of operation of the plant is presented in the paper. After aneffective start–up period of about 6-7 months (totally 10 months) over 80% nitrogen removalefficiency was obtained and nitrogen removal rates reached almost 2g m-2 d at a temperature of28 oC. The nitrite production was the limiting step for the anammox reaction. Intermittentaeration was used to secure a suitable ratio of aerobic and anaerobic conditions in the biofilm.Inhibition of the ammonia oxidizers was observed at concentrations over 15 mg l-1 of freeammonia as NH3. The free ammonia was controlled by a combination of different strategiesincluding aeration time, influent load and effluent recirculation. Conductivity proved to be asuitable tool for the process monitoring.
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