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  • 1.
    Owusu-Agyeman, Isaac
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Eyice, Özge
    Cetecioglu, Zeynep
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    The study of structure of anaerobic granules and methane producing pathways of pilot-scale UASB reactors treating municipal wastewater under sub-mesophilic conditions2019In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 290, article id 121733Article in journal (Refereed)
    Abstract [en]

    This study was carried out to investigate the relationship between the methane producing pathways and the characteristics of anaerobic granules treating municipal wastewater. For this purpose, two pilot scale upflow anaerobic sludge blanket reactors with different granule size distribution (1-2 mm and 3-4 mm) were investigated at operating temperatures of 20 degrees C and 28 degrees C for 239 days. There was an increased and stable biogas production when temperature was elevated to 28 degrees C likely due to reduction in methane solubility. Larger granules had multi-layered internal microstructures with higher acetoclastic methanogenic activities (250-437 mL CH(4)g(-1) VS d(-1)) than smaller granules (150-260 mL CH(4)g(-1) VS d(-1)). The relative abundance of acetoclastic methanogens of larger granules was higher, confirming acetoclastic methane producing pathway was more prominent. However, there was no significant difference in the performance of the two reactors because they were operating below their capacities in terms of organic loading rate to volatile solids ratio.

  • 2.
    Persson, Frank
    et al.
    Chalmers, Div Water Environm Technol, Dept Civil & Environm Engn, SE-41296 Gothenburg, Sweden..
    Suarez, Carolina
    Univ Gothenburg, Dept Chem & Mol Biol, SE-40530 Gothenburg, Sweden..
    Hermansson, Malte
    Univ Gothenburg, Dept Chem & Mol Biol, SE-40530 Gothenburg, Sweden..
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Sultana, Razia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Wilen, Britt-Marie
    Chalmers, Div Water Environm Technol, Dept Civil & Environm Engn, SE-41296 Gothenburg, Sweden..
    Community structure of partial nitritation-anammox biofilms at decreasing substrate concentrations and low temperature2017In: Microbial Biotechnology, ISSN 1751-7907, E-ISSN 1751-7915, Vol. 10, no 4, p. 761-772Article in journal (Refereed)
    Abstract [en]

    Partial nitritation-anammox (PNA) permits energy effective nitrogen removal. Today PNA is used for treatment of concentrated and warm side streams at wastewater treatment plants, but not the more diluted and colder main stream. To implement PNA in the main stream, better knowledge about microbial communities at the typical environmental conditions is necessary. In order to investigate the response of PNA microbial communities to decreasing substrate availability, we have operated a moving bed biofilm reactor (MBBR) at decreasing reactor concentrations (311-27mg-N l(-1) of ammonium) and low temperature (13 degrees C) for 302days and investigated the biofilm community using high throughput amplicon sequencing; quantitative PCR; and fluorescence insitu hybridization. The anammox bacteria (Ca. Brocadia) constituted a large fraction of the biomass with fewer aerobic ammonia oxidizing bacteria (AOB) and even less nitrite oxidizing bacteria (NOB; Nitrotoga, Nitrospira and Nitrobacter). Still, NOB had considerable impact on the process performance. The anammox bacteria, AOB and NOB all harboured more than one population, indicating some diversity, and the heterotrophic bacterial community was diverse (seven phyla). Despite the downshifts in substrate availability, changes in the relative abundance and composition of anammox bacteria, AOB and NOB were small and also the heterotrophic community showed little changes in composition. This indicates stability of PNA MBBR communities towards decreasing substrate availability and suggests that even heterotrophic bacteria are integral components of these communities.

  • 3.
    Plaza, Elzbieta
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology. KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Levlin, Erik
    Morling, Stig
    Falk, Lina
    Pilotförsök med MABR på Ekeby avloppsreningsverk: Teknisk rapport av ESEM, KTH & Sweco2018Report (Other academic)
    Abstract [en]

    This pilot project with membrane aerated biofilm reactor (MABR) was performed at Ekeby sewage treatment plant in Eskilstuna, Sweden. Ekeby faces a future challenge with growing population, where higher processing capacity is needed and new requirements for total nitrogen <10 mg/L in the discharge, according to the new standard. MABR, a newly developed technology with simultaneous nitrification and denitrification, was chosen as a promising technique to cope with the challenge. The trials were conducted for a 230 days period from July 12, 2017 to February 28, 2018.The pilot was designed as an activated sludge process with pre-denitrification with first an anaerobic tank where Zeelung membrane modules were placed, followed by an aerobic tank and finally a sedimentation unit where the return sludge was returned to the inlet. The feed water for the pilot comes from the treatkment plant's pre-sedimentation. Several analyzes were made on the inflow to the MABR reactor, in the volume with the Zeelung module, in the aerated volume and in outflow from the sedimentation tank. Ammonium content in incoming flow was 27 mg/L at the start of the trial to decrease to an average of 16 mg/L after day 60. Temperature in the inflow decreased during the experiment from 20 °C to 10 °C at day 124, to then stabilize on 12 °C. The reduction of organic material, such as BOD7, decreased from 90% at the start to 60% at the end of the trial, which is attributable to a lack of sludge separation in the final sedimentation.Nitrogen separation increased from 32 % at the start of the trial to an average of 53 % at the end of the trial. Nitrification in the Zeelung module increased from 27 % of oxidized nitrogen at the start of the experiment to 45 % at the end of the experiment. Along with the nitrification in the air volume, the nitrification of ammonium was almost total until day 175, January 3, when it fell sharply to the minimum 40 % on January 23, day 195, due to a combination of load and sludge from the sedimentation stage resulting in a shortened and insufficient sludge age. When the availability of organic carbon for denitrification was considered insufficient to cope with operation at low water temperature, and in combination with low levels of dissolved COD in incoming sewage, acetate was added from day 121. Prior to the addition of carbon source, the denitrification rate was on average 40% after the addition of carbon source, go up to 60% at the end of the test. The processes in the Zeelung module showed better operational stability than in the subsequent aerobic reactor.

  • 4.
    Salmistraro, Marco
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Fernández, I.
    Dosta, J.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Mata, J.
    Mainstream Deammonification: Preliminary Experience Employing Granular AOB-Enriched Biomass at Low DO Values2017In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 228, no 5, article id 178Article in journal (Refereed)
    Abstract [en]

    The deammonification process represents one of the most convenient pathways for nitrogen removal from wastewater. A great deal of scientific articles dwells on the treatment of sidestream fluxes, whereas applications to mainstream waters represent a novel field. Among the general challenges of deammonification, one of the most important is the effective selection of ammonia oxidizers (AOB) over nitrite oxidizers (NOB), but also the typical slow start-up periods. In addition to such issues, mainstream deammonification has to face water temperatures and alkalinity reserves lower than those of sidestream fluxes and higher content of organic matter. An attempt was made to tackle such challenges by employing a lab-scale plant; low dissolved oxygen (DO) values (average 0.78 mg/L) and granular AOB-enriched biomass were used in order to address exclusion of nitrite oxidizers. The granules also allowed better biomass retention. The hydraulic retention time (HRT) was established initially at 24 h and later decreased to 12 h, as to possibly enhance the performance of the reactor. After 52 days of operation, Anammox biomass was also inoculated to the reactor. The results showed a maximum nitrogen removal efficiency of 54%. Moreover, little quantities of nitrates were observed throughout the experiment (<5 mg N/L twice, under the limit of quantification the rest of the sampling days), meaning that NOB out-selection techniques worked properly. Retention of biomass was also positively addressed and yielded a final SRT value of 15.6 days. Therefore, the proposed solution for mainstream deammonification was demonstrated to be promising and more research would be necessary to optimize it.

  • 5.
    Trela, Jozef
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Innovative technologies in municipal wastewater treatment plants in Sweden to improve Baltic Sea water quality2018In: E3S Web of Conferences, EDP Sciences , 2018Conference paper (Refereed)
    Abstract [en]

    The article presents new trends in the treatment of municipal wastewater in Sweden caused by the constantly increasing requirements for discharging pollutants into Baltic Sea waters. The development of new technologies for nitrogen removal, pharmaceutical residues removal and the possibility of using membrane processes in wastewater treatment is presented. The state of research on innovative wastewater treatment processes at the level of pilot-scale tests and their implementation in full technical scale has been described. These technologies can allow the application of new, economical and environmentally friendly wastewater treatment processes based on biological, chemical and physical methods. Swedish wastewater treatment plants are preparing to meet the new conditions required for discharged wastewater with a value of 6 mg N/L for total nitrogen and 0.2 mg P/L for total phosphorus. This requires large investments in the reconstruction of municipal wastewater treatment plants and the introduction of new treatment processes.

  • 6.
    Trojanowicz, K.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. St Pigon Krosno State Coll, Dept Environm Engn, Rynek 1, PL-38400 Krosno, Poland..
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Swedish Environm Inst, IVL, Stockholm, Sweden..
    Model extension, calibration and validation of partial nitritation-anammox process in moving bed biofilm reactor (MBBR) for reject and mainstream wastewater2019In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 40, no 9, p. 1079-1100Article in journal (Refereed)
    Abstract [en]

    In the paper, the extension of mathematical model of partial nitritation-anammox process in a moving bed biofilm reactor (MBBR) is presented. The model was calibrated with a set of kinetic, stoichiometric and biofilm parameters, whose values were taken from the literature and batch tests. The model was validated with data obtained from: laboratory batch experiments, pilot-scale MBBR for a reject water deammonification operated at Himmerfjarden wastewater treatment and pilot-scale MBBR for mainstream wastewater deammonification at Hammarby Sjostadsverk research facility, Sweden. Simulations were conducted in AQUASIM software. The proposed, extended model proved to be useful for simulating of partial nitritation/anammox process in biofilm reactor both for reject water and mainstream wastewater at variable substrate concentrations (influent total ammonium-nitrogen concentration of 530 +/- 68; 45 +/- 2.6 and 38 +/- 3 gN/m(3) - for reject water - and two cases of mainstream wastewater treatment, respectively), temperature (24 +/- 2.8; 15 +/- 1.1 and 18 +/- 0.5 degrees C), pH (7.8 +/- 0.2; 7.3 +/- 0.1 and 7.4 +/- 0.1) and aeration patterns (continuous aeration and intermittent aeration with variable dissolved oxygen concentrations and length of aerated and anoxic phases). The model can be utilized for optimizing and testing different operational strategies of deammonification process in biofilm systems. [GRAPHICS] .

  • 7.
    Trojanowicz, Karol
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. St Pigon Krosno State Coll, Dept Environm Engn, Rynek 1, PL-38400 Krosno, Poland.Dev Environm Sci & Engn, Stockholm, Sweden..
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Possible mechanism of efficient mainstream partial nitritation/anammox (PN/A) in hybrid bioreactors (IFAS)2019In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487XArticle in journal (Refereed)
    Abstract [en]

    An explanation of possible mechanism of efficient PN/A in hybrid bioreactors was presented. The bottleneck process is nitritation. Surplus nitrite production by ammonium oxidizing bacteria (AOB) is required for assuring the activity of anammox bacteria and eliminating nitrite oxidizing bacteria (NOB). It will be possible if nitrogen removal rate by AOB (r(N_AOB)) is higher than NOB (r(N_NOB)). It was shown that in biofilm AnAOB bacteria should out-compete NOB, whereas nitrogen transformation rates by AOB are usually lower than NOB. However, the growth of r-AOB in activated sludge allows out-selecting NOB. Impact of ammonium-, nitrite-nitrogen and suspended biomass concentration in hybrid PN/A systems on nitrogen removal rates in the temperature ranges from 10 degrees C to 25 degrees C was presented and discussed. Because bulk liquid ammonium nitrogen concentration can be higher in SBR bioreactors (after certain period of time after aeration starts) or in the initial zones of plug-flow systems than in fully mixed systems, conditions for running efficient PN/A are more favourable in intermittently aerated 'IFAS-SBR' or 'IFAS-plug flow' bioreactors.

  • 8.
    Yang, Jingjing
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Swedish Environm Res Inst IVL, Sweden.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Nitrous oxide emissions from one-step partial nitritation/anammox processes2016In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 74, no 12, p. 2870-2878Article in journal (Refereed)
    Abstract [en]

    Measurements of nitrous oxide were made at pilot-and full-scale plants to evaluate greenhouse gas emissions from one-step partial nitritation/anammox processes applied in moving bed biofilm reactors treating reject water. It was found that 0.51-1.29% and 0.35-1.33% of the total nitrogen loads in the pilot-and full-scale reactor, respectively, were emitted as nitrous oxide. Between 80 and 90% of nitrous oxide emissions were in gaseous form and the rest amount was found in the reactor effluent; over 90% of nitrous oxide emissions occurred in the aerated period and less than 8% in the non-aerated period in the full-scale study. Nitrous oxide productions/consumptions were closely related to aeration and the nitrogen loads applied in the system.

1 - 8 of 8
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