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  • 1.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Surmacz-Gorska, J.
    Dissolved oxygen as a factor influencing nitrogen removal rates in a one-stage system with partial nitritation and Anammox process2011In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 64, no 5, p. 1009-1015Article in journal (Refereed)
    Abstract [en]

    A biofilm system with Kaldnes biofilm carrier was used in these studies to cultivate bacteria responsible for both partial nitritation and Anammox processes. Due to co-existence of oxygen and oxygen-free zones within the biofilm depth, both processes can occur in a single reactor. Oxygen that inhibits the Anammox process is consumed in the outer layer of the biofilm and in this way Anammox bacteria are protected from oxygen. The impact of oxygen concentration on nitrogen removal rates was investigated in the pilot plant (2.1 m(3)), supplied with reject water from the Himmerfjarden Waste Water Treatment Plant. The results of batch tests showed that the highest nitrogen removal rates were obtained for a dissolved oxygen (DO) concentration around 3 g O(2) m(-3). At a DO concentration of 4 g O(2) m(-3), an increase of nitrite and nitrate nitrogen concentrations in the batch reactor were observed. The average nitrogen removal rate in the pilot plant during a whole operating period oscillated around 1.3 g N m(-2)d(-1) (0.3 +/- 0.1 kg N m(-3)d(-1)) at the average dissolved oxygen concentration of 2.3 g O(2) m(-3). The maximum value of a nitrogen removal rate amounted to 1.9 g N m(-2)d(-1) (0.47 kg N m(-3)d(-1)) and was observed for a DO concentration equal to 2.5 g O(2) m(-3). It was observed that increase of biofilm thickness during the operational period, had no influence on nitrogen removal rates in the pilot plant.

  • 2.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Szatkowska, Beata
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Płaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Surmacz-Górska, Joanna
    Nitrogen removal rates at a technical-scale pilot plant with the one-stage partial nitritation/Anammox process.2006In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 54, no 8, p. 209-217Article in journal (Refereed)
    Abstract [en]

    Traditional nitrification/denitrification is not suitable for nitrogen removal when wastewater contains high concentrations of ammonium nitrogen and low concentrations of biodegradable carbon. Recently, a deammonification process was developed and proposed as a new technology for treatment of such streams. This process relies on a stable interaction between aerobic bacteria Nitrosomonas, that accomplish partial nitritation and anaerobic bacteria Planctomycetales, which conduct the Anammox reaction. Simultaneous performance of these two processes can lead to a complete autotrophic nitrogen removal in one single reactor. The experiments where nitrogen was removed in one reactor were performed at a technical-scale moving-bed pilot plant, filled with Kaldnes rings and supplied with supernatant after dewatering of digested sludge. It was found that a nitrogen removal rate obtained at the pilot plant was 1.9 g m(-2) d(-1). Parallel to the pilot plant run, a series of batch tests were carried out under anoxic and aerobic conditions. Within the batch tests, where the pilot plant's conditions were simulated, removal rates reached up to 3g N m(-2) d(-1). Moreover, the batch tests with inhibition of Nitrosomonas showed that only the Anammox bacteria (not anoxic removal by Nitrosomonas) are responsible for nitrogen removal.

  • 3.
    Cema, Grzegorz
    et al.
    Environmental Biotechnology Department, Silesian University of Technology.
    Żabczyński, S.
    Environmental Biotechnology Department, Silesian University of Technology.
    Zabłocka-Godlewska, E.
    Environmental Biotechnology Department, Silesian University of Technology.
    Raszka, A.
    Environmental Biotechnology Department, Silesian University of Technology.
    Surmacz-Górska, J.
    Environmental Biotechnology Department, Silesian University of Technology.
    Biological nitrogen removal from landfill leachate by deammonification assisted by heterotrophic denitrification in a rotating biological contactor (RBC)2007In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 55, no 8-9, p. 35-42Article in journal (Refereed)
    Abstract [en]

    Due to negative environmental effects of nitrogen discharge to recipients and increasingly W stringent effluent standards, effective nitrogen removal is necessity. Biological methods are the simplest in and cheapest way to treat wastewater; however, it may become an extremely expensive option when high influent nitrogen concentrations are measured and there is a lack of biodegradable organic carbon. Therefore, there is a great need to find new solutions and improve existing technologies. The deammonification is an excellent example of such a new process that requires considerably low CA amounts of organic carbon and oxygen in comparison to conventional nitrification/denitrification. The main objective of presented research was to investigate an Anammox process accompanied with autotrophic nitrification and heterotrophic denitrification in one rotating biological contactor (RBC). During the research period, it was possible to carry out the Anammox process in low temperature below 20 degrees C. Additionally, it was found that the process is insensitive to high nitrite concentration in the reactor, up to 100 g NO2-N m(-3), resulting only in a temporary decrease in removal rates. Furthermore, analysis of data indicated that the Stover-Kincannon model can be used for the description of ammonium and nitrite removal processes.

  • 4.
    Darracq, Amélie
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Greffe, Fanny
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Hannerz, Fredrik
    Destouni, G.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Resources Engineering.
    Nutrient transport scenarios in a changing Stockholm and Mälaren valley region, Sweden2005In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 51, no 3-4, p. 31-38Article in journal (Refereed)
    Abstract [en]

    Norrstrom catchment, west of Stockholm, covers most of the Malaren valley. Provision of drinking water from Lake Malaren is an absolute precondition for continued growth in the region. Stockholm County's population is expected to increase by 600,000 people before 2030. Current climate change predictions anticipate significant temperature and precipitation increases. We implement the PolFlow model embedded in PCRaster for quantifying water and substances fluxes on the catchment scale over a 30-year time horizon. We formulate scenarios for changes in water quality and quantity due to climate change and population development. Results indicate a mild impact from climate change on surface flow rates but substantial effects on sub-surface residence times. Population development slightly affects nutrients loads. Using source apportionment and sensitivity analysis, we identify a number of critical parameters/processes to be further studied, in order for future results to be more reliable and usable in a water resources management context.

  • 5.
    Desta, Adey F.
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology (closed September 2009).
    Dalhammer, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology (closed September 2009).
    Kittuva, Gunatrana R.
    KTH, School of Biotechnology (BIO), Environmental Microbiology (closed September 2009).
    A modified culture-based study of bacterial community composition in a tannery wastewater treatment plant2010In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 62, no 11, p. 2543-2549Article in journal (Refereed)
    Abstract [en]

    Though culture-independent methods have been used in preference to traditional isolation techniques for characterization of microbial community of wastewater treatment plants, it is difficult to widely apply this approach in resource-poor countries. The present study aimed to develop a test to identify the culturable portion of bacterial community in a high-strength wastewater. Wastewater samples were collected from nitrification-denitrification and settling tanks of the treatment plant of Elmo Leather AB tannery located in Boras, Sweden. After cultivating on nutrient agar with the optimal dilution (10(-2)), phenotypic and biochemical identification of the bacteria were done with colony morphology, Gram reaction, growth on MacConkey, phenylethanol media, triple sugar Iron agar slants, catalase and oxidase tests. Biochemical grouping of the isolates was done based on their test results for MacConkey, phenylethanol media, triple sugar Iron agar and oxidase test reaction. From the biochemical groups, isolates were randomly selected for API test and 16SrRNA gene sequencing. The isolates from the denitrification, nitrification tank were identified to be Paracoccus denitrificans (67%), Azoarcus spp (3%) and Spingomonas wittichii (1%). From the settling tank, Paracoccus denitrificans (22%), Corynebacterium freneyi (20%) and Bacillus cereus (1%) were identified. The grouping based on biochemical test results as well as the identification based on sequencing has shown coherence except for discrepancies with the API test. The preliminary implications of the grouping based on culture-based characteristics and its potential application for resource-limited environmental microbial studies is discussed.

  • 6. Durdu, Oe F.
    et al.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Modeling water and nutrients fluxes in the Buyuk Menderes drainage basin, Turkey2009In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 59, no 3, p. 531-541Article in journal (Refereed)
    Abstract [en]

    Buyuk Menderes catchment, located in the southwestern part of Turkey, is one of the most populated river basins in Turkey with 2.5 millions inhabitants. Due to increasing activities in agriculture and industrial sectors, water resources management in the basin is one of the biggest matters for the future. During the past decade, it has been observed a basinwide shift to larger monocultural, intensively operated farm units. Therefore, there is land use conversion from native lands to agriculture. The threat of nutrients pollution, nitrogen and phosphorus, has become a preoccupation since many lands and rivers undergo a eutrophication process. The discharge of nutrients from Buyuk Menderes basin to the Aegean Sea through Buyuk Menderes river also needs to be reduced in order to bring the eutrophication problems under lasting control. In this paper, the PolFlow model embedded in PCraster is applied to the catchment for quantifying water and substances fluxes for the five-year period, 1999-2004. The implementation of the model in the catchment allows describing the water balance and thus nutrient transport on the landscape surface but also through the soil and aquifer's layers. Modeling process is complicated by the transfer of nutrients from diffuse and point-source emissions, managed by retention and periodic release from storages within the catchment. Modeling diffuse and point-source nutrient emissions contribution to river loads can be improved by better knowledge about spatial and temporal distribution of this retention and release in the basin.

  • 7. Farahbakhshazad, Neda
    Phosphorus removal in a vertical upflow constructed wetland system2003In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 48, no 5, p. 43-50Conference paper (Refereed)
    Abstract [en]

    Mechanisms for P removal in a vertical upflow macrophyte system were studied in controlled laboratory columns filled with sand and planted with Phragmites australis. Substrate P removal was shown to increase with flow rate, a parameter which can be enhanced through effluent recirculation. An alternative substrate (leca, light expanded clay aggregate) provided improved equilibrium adsorption characteristics, but uncrushed and within the kinetic constraints of a macrophyte system gave no improvement for P adsorption over sand. Intermittent loading of the sand based macrophyte system permitted control of the P concentration, with lower effluent peak concentrations for increased resting interval (no P inflow). Where P loading was targeted, continuous flow provided the optimum mass removal conditions.

  • 8. Flyborg, L.
    et al.
    Björlenius, Berndt
    Water Resource Engineering, Lund University.
    Persson, K.M.
    Can treated municipal wastewater be reused after ozonation and nanofiltration?: Results from a pilot study of pharmaceutical remval in Henriksdal WWTP, Sweden2010In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 61, no 5, p. 1113-1120Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to evaluate the potential of nanofiltration (NF) and ozonation for indirect potable reuse in terms of pharmaceutical residuals. To simultaneously obtain a reasonable retentate volume for further treatment, the tests were performed at a high volume reduction factor (VRF) of 60. The feed to the pilot plant was the effluent from a BNR plant with a final process step of chemical precipitation and rapid sand filtration. Two tests were performed 1) nanofiltration of treated wastewater followed by ozonation and 2) ozonated treated wastewater as feed to NF. Of the 95 pharmaceuticals analysed, three were not removed to the quantification limit, oxazepam in the first test and glibenclamide and ketoprofen in the second. The water quality after the two processes was similar, with an overall removal of pharmaceutical residuals of 99%. There are two advantages of ozonated water as feed to NF-a higher specific flux of 35% and a potential removal of ozonation by-products. The retention of some pharmaceuticals by NF was lower than anticipated, the major removal occurring in the ozonation. A tighter NF or RO is required in order to achieve higher pharmaceutical retention for further treatment of the retentate.

  • 9.
    Gut, Luiza
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Plaza, Ela
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Hultman, Bengt
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Bosander, Jan
    Combined partial nitritation/Anammox system for treatment of digester supernatant2006In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 53, no 12, p. 149-159Article in journal (Refereed)
    Abstract [en]

    One-year (2004) comprehensive investigations in a semi-industrial pilot plant (5 m(3)) were carried out with the aim of assessing the influence of operational parameters on the partial nitritation/Anammox system performance. In the system designed as a moving-bed biofilm reactor, the influent nitrogen load to the Anammox reactor was progressively increased and a stable Anammox bacterial culture was obtained. Interaction between subsequent, aerobic and anaerobic conditions in the partial nitritation and Anammox reactors, respectively, granted conditions to remove nitrogen through the nitrite route. It implies that the oxygen supply can be limited to a high extent. A control strategy for the partial nitritation step relied on concomitant adjustment of the air supply with a variable influent nitrogen load, which can be monitored by both pH and conductivity measurements. In the Anammox reactor, an influent nitrite-to-ammonium ratio plays a vital role in obtaining efficient nitrogen removal. During the 1-year experimental period, the Anammox reactor was operated steadily and average nitrogen removal efficiency was 84% with 97% as the maximum value.

  • 10. Hallberg, M.
    et al.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Byman, L.
    Svenstam, G.
    Norling, M.
    Treatment of tunnel wash water and implications for its disposal2014In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 69, no 10, p. 2029-2035Article in journal (Refereed)
    Abstract [en]

    The use of road tunnels in urban areas creates water pollution problems, since the tunnels must be frequently cleaned for traffic safety reasons. The washing generates extensive volumes of highly polluted water, for example, more than fivefold higher concentrations of suspended solids compared to highway runoff. The pollutants in the wash water have an affinity for particulate material, so sedimentation should be a viable treatment option. In this study, 12 in situ sedimentation trials were carried out on tunnel wash water, with and without addition of chemical flocculent. Initial suspended solids concentration ranged from 804 to 9,690 mg/L. With sedimentation times of less than 24 hours and use of a chemical flocculent, it was possible to reach low concentrations of suspended solids (< 15 mg/L), PAH (< 0.1 mu g/L), As (< 1.0 mu g/L), Cd (< 0.05 mu g/L), Hg (< 0.02 g/L), Fe (< 200 mu g/L), Ni (< 8 mu g/L), Pb (< 0.5 mu g/L), Zn (< 60 mu g/L) and Cr (< 8 mu g/L). Acute Microtox (R) toxicity, mainly attributed to detergents used for the tunnel wash, decreased significantly at low suspended solids concentrations after sedimentation using a flocculent. The tunnel wash water did not inhibit nitrification. The treated water should be suitable for discharge into recipient waters or a wastewater treatment plant.

  • 11.
    Hyder, A. H. M. Golam
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Begum, Shamim A.
    Egiebor, Nosa O.
    Sorption studies of Cr(VI) from aqueous solution using bio-char as an adsorbent2014In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 69, no 11, p. 2265-2271Article in journal (Refereed)
    Abstract [en]

    The characteristics of sorption of hexavalent chromium (Cr(VI)) onto bio-char derived from wood chips (spruce, pine, and fir) were evaluated as a function of pH, initial Cr(VI) concentration and bio-char dosage using synthetic wastewater in batch tests. The initial Cr(VI) concentrations were varied between 10 and 500 mg/L to investigate equilibrium, kinetics, and isotherms of the sorption process. About 100% of Cr(VI) was removed at pH 2 with initial Cr(VI) concentration of 10 mg/L using 4 g of bio-char after 5 hours of sorption reaction. The maximum sorption capacity of the bio-char was 1.717 mg/g for an initial Cr(VI) concentration of 500 mg/L after 5 hours. The sorption kinetics of total Cr onto bio-char followed the second-order kinetic model. The Langmuir isotherm model provided the best fit for total Cr sorption onto bio-char. The bio-char used is a co-product of a down draft gasifier that uses the derived syngas to produce electricity. Bio-char as a low cost adsorbent demonstrated promising results for removal of Cr(VI) from aqueous solution. The findings of this study would be useful in designing a filtration unit with bio-char in a full-scale water and wastewater treatment plant for the Cr(VI) removal from contaminated waters.

  • 12. Jonch-Clausen, T
    et al.
    Cederwall, Klas
    KTH.
    Workshop 1 (synthesis): multipurpose stream management strategies2004In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 49, no 7, p. 87-88Article in journal (Refereed)
    Abstract [en]

    For a meaningful dialogue on balancing water uses between stakeholders in a river basin, adequate information and proper understanding, knowledge and access to reliable data are essential for all parties. Technological and economic components in water resources management have limited significance without the social context, and the legal framework plays a key role in the dialogue between stakeholders at all levels. Other aspects that fit into strategic planning and management of water resources projects are risk assessment, ecosystem requirements, credibility and trust building.

  • 13. Kulabako, Robinah
    et al.
    Nalubega, Mai
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Shallow groundwater quality in peri-urban KampalaIn: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732Article in journal (Other academic)
  • 14.
    Larsdotter, Karin
    et al.
    KTH, Superseded Departments.
    Norström, Anna
    KTH, Superseded Departments.
    Gumaelius, Lena
    KTH, Superseded Departments.
    Jansen, Jes La Cour
    Dalhammar, Gunnel
    KTH, Superseded Departments.
    A small scale hydroponics wastewater treatment system under Swedish conditions2003In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 48, no 11, p. 161-167Article in journal (Refereed)
    Abstract [en]

    A treatment plant using conventional biological treatment combined with hydroponics and microalgae is constructed in a greenhouse in the area of Stockholm, Sweden. The treatment plant is built for research purposes and presently treats 0.559 m(3) of domestic wastewater from the surrounding area per day. The system uses anoxic pre-denitrification followed by aerobic tanks for nitrification and plant growth. A microalgal step further reduces phosphorus, and a final sand filter polishes the water. During a three week period in July 2002 the treatment capacity of this system was evaluated with respect to removal of organic matter, phosphorus and nitrogen. 90% COD removal was obtained early in the system. Nitrification and denitrification was well established with total nitrogen reduction of 72%. Phosphorus was removed by 47% in the process. However, higher phosphorus removal values are expected as the microalgal step will be further developed. The results show that acceptable treatment can be achieved using this kind of system. Further optimisation of the system will lead to clean water as well as valuable plants to be harvested from the nutrient rich wastewater.

  • 15.
    Levlin, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Löwén, Monica
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Stark, Kristina
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Hultman, Bengt
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Effects of phosphorus recovery requirements on Swedish sludge management2002In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 46, no 4-5, p. 435-440Article in journal (Refereed)
    Abstract [en]

    Expected requirements of phosphorus recovery, restrictions on sludge disposal on landfill, and difficulties in obtaining consensus on sludge use on agricultural land has led to several development works in Sweden to change sludge management methods. Especially sludge fractionation has gained interest including following steps to recover products and separate transfer of toxic substances into a small stream. Commercial systems are offered based on technology by Cambi/KREPRO and BioCon and other companies and many other methods are under development. Iron salts are widely used in Sweden as precipitation agents for phosphorus removal and this technology has some disadvantages for phosphorus recovery compared with the use of biological phosphorus removal. The amount of chemicals needed for a KREPRO or a BioCon system was calculated for a treatment plant which has an addition of iron salt resulting in 1,900 mole Fe per tonne DS. The result was compared with the chemical consumption of recovery systems installed at plants with lower use of iron for precipitation. The chemical consumption in equivalents per tonne DS was found to be 5,000 + 6,000 * (molar ratio iron to phosphorus).

  • 16. Lindblom, E.
    et al.
    Arnell, M.
    Flores-Alsina, X.
    Stenström, F.
    Gustavsson, D. J. I.
    Yang, James
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    Jeppsson, U.
    Dynamic modelling of nitrous oxide emissions from three Swedish sludge liquor treatment systems2016In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 73, no 4, p. 798-806Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to model the dynamics and validate the results of nitrous oxide (N2O) emissions from three Swedish nitrifying/denitrifying, nitritation and anammox systems treating real anaerobic digester sludge liquor. The Activated Sludge Model No. 1 is extended to describe N2O production by both heterotrophic and autotrophic denitrification. In addition, mass transfer equations are implemented to characterize the dynamics of N2O in the water and the gas phases. The biochemical model is simulated and validated for two hydraulic patterns: (1) a sequencing batch reactor; and (2) a moving-bed biofilm reactor. Results show that the calibrated model is partly capable of reproducing the behaviour of N2O as well as the nitritation/nitrification/denitrification dynamics. However, the results emphasize that additional work is required before N2O emissions from sludge liquor treatment plants can be generally predicted with high certainty by simulations. Continued efforts should focus on determining the switching conditions for different N2O formation pathways and, if full-scale data are used, more detailed modelling of the measurement devices might improve the conclusions that can be drawn.

  • 17.
    Malovanyy, Andriy
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Lviv Polytech Natl Univ, Dept Ind Ecol & Sustainable Environm Management, Ukraine.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Malovanyy, Myroslav
    Combination of ion exchange and partial nitritation/Anammox process for ammonium removal from mainstream municipal wastewater2014In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 70, no 1, p. 144-151Article in journal (Refereed)
    Abstract [en]

    In this study, a new technology of nitrogen removal from mainstream municipal wastewater is proposed. It is based on ammonium removal by ion exchange and regeneration of ion exchange material with 10-30 g/L NaCl solution with further nitrogen removal from spent regenerant by partial nitritation/Anammox process. Influence of regenerant strength on performance of ion exchange and biological parts of the proposed technology was evaluated. Moreover, the technology was tested in batch mode using pretreated municipal wastewater, strong acid cation (SAC) resin and partial nitritation/Anammox biomass. It was shown that with ion exchange it is possible to remove 99.9% of ammonium from wastewater while increasing the concentration of ammonium in spent regenerant by 18 times. Up to 95% of nitrogen from spent regenerant, produced by regeneration of SAC resin with 10 g/L NaCl solution, was removed biologically by partial nitritation/Anammox biomass. Moreover, the possibilities of integration of the technology into municipal wastewater treatment technology, and the challenges and advantages are discussed.

  • 18.
    Mbwele, Lydia
    et al.
    KTH, Superseded Departments, Biotechnology.
    Rubindamayugi, M.
    Kivaisi, A.
    Dalhammar, Gunnel
    KTH, Superseded Departments, Biotechnology.
    Performance of a small wastewater stabilisation pond system in tropical climate in Dar es Salaam, Tanzania2003In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 48, no 11-12, p. 187-191Article in journal (Refereed)
    Abstract [en]

    Waste stabilisation ponds (WSP) are widely used in Tanzania. Their traditional design focuses on BOD and pathogen removal, but nutrient removal is equally important. WSP performance was evaluated to come up with information that would be used to evaluate pond performance. Samples were analysed twice a month for six months. Results showed total and faecal coliform removal by 4 log units (99.96 and 99.98% respectively). There was partial reduction of COD, BOD, (46% and 27% respectively), conductivity and total dissolved solids (32.6 and 32.4% respectively). Variation for the nutrients like inorganic phosphorus, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen was not consistent and there was practically no reduction, although there is some nitrification taking place. From this study it may be concluded that BOD and nutrients may not be useful to evaluate pond performance. Instead parameters such as conductivity, total dissolved solids, coliform bacteria, dissolved oxygen, pH and chlorophyll would be suitable for that purpose, due to their consistent variation within cells of the pond system. But BOD and nutrient removal are important and have to be improved to enhance treatment in the WSP.

  • 19. Mikosz, J.
    et al.
    Plaza, Elzbieta
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Kurbiel, A.
    Use of computer simulation for cycle length adjustment in sequencing batch reactor2001In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 43, no 3, p. 61-68Article in journal (Refereed)
    Abstract [en]

    The city of Nowy Targ located in Poland's highland operates the WWTP with classic SBR technology. In winter some decrease in process efficiency was observed. The research described in the paper was aimed at using computer simulation to adjust SBR cycle length and structure in order to minimize the effects of low wastewater temperature on biological CNP removal. The simulations performed at 6 degreesC wastewater temperature showed that switching from 6 to 8 hours cycle and extension of the aeration phase length from 2.75 to 5 hours will increase the effectiveness of biological nitrification and biological phosphorus removal. The change in practice will not affect COD value in the effluent. Based on the simulation results a new SBR operational strategy was proposed for Nowy Targ WWTP.

  • 20. Morling, Stig
    Performance of an SBR-pla nt for advanced nutrient removal, using septic sludge as a carbon source2001In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 43, no 3, p. 131-138Article in journal (Refereed)
    Abstract [en]

    The Tjustvik SBR-plant outside Stockholm, Sweden has been in operation for four years. The plant has to meet stringent effluent standards, BOD7 < 10 PPM, total N < 15 PPM and total P < 0.3 PPM. The plant is a typical two reactor SBR-plant, sized for about 15 000 inhabitants, During the first year of operation there were difficulties in meeting the P consent level. The difficulties were linked to a deficit of available organic carbon and a secondary phosphorus release. The problem was solved with the addition of septic sludge, in an amount equivalent to about 10,000 to 15,000 inhabitants with respect to the BOD-load. The altered operation resulted in a very stable and good effluent quality from the plant that has been maintained ever since, giving typical discharge levels as follows: BOD7, < 3 mg/l; Total-P, < 0.15 mg/l; Total-N, < 7 mg/l; NH4-N,< 1 mg/l. The change of process saved the community from a major investment in a separate treatment facility for the septic sludge. The stabilisation degree of the waste activated sludge is sufficient to by pass the anaerobic digestion for the time being, In the beginning, the SBR-process stability played an unwanted role during start up as it maintained a secondary phosphorus release for a considerable time. Later the process stability became an asset as the varying loads from the septic sludge addition were handled with very good results.

  • 21.
    Nikolic, Alexander
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Hultman, Bengt
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Chemical denitrification for nitrogen removal from landfill leachate2005In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 52, no 10-11, p. 509-516Article in journal (Refereed)
    Abstract [en]

    A new system that removes nitrogen from landfill leachate and other waste waters with similar properties has been proposed with nitritation (i.e. oxidation of ammonium to nitrite) of half of the influent ammonium followed by chemical denitrification with a reaction between equal amounts of ammonium and nitrite to form nitrogen gas. Chemical denitrification occurs at high concentrations and the reactions were studied in combination with a concentration step. Studied concentration methods were freezing/thawing and evaporation/drying. Chemical denitrification is well-known in inorganic chemistry and has been observed in natural systems. Studies in laboratory were focused on chemical denitrification and showed that nearly complete removal of soluble nitrogen can be obtained in evaporation/drying of water solutions or leachate with equal amounts of ammonium and nitrite. Freezing/drying was less efficient with a removal of about 50-60% at high initial concentrations. Chemical denitrification is much influenced by concentration, pH-value, temperature and some compounds in leachate have an inhibiting effect on the reaction. Factors as safety (ammonium nitrite as a salt is explosive above 60 degrees C) and possible side-reactions as formation of ammonia and nitrogen oxides must be carefully evaluated before use in full-scale. Conductivity is a suitable parameter to follow-up the chemical denitrification process.

  • 22.
    Norström, Anna
    et al.
    KTH, School of Biotechnology (BIO).
    La Cour Jansen, Jes
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO).
    Energy savings versus year‐round production in a small hydroponic system for wastewater treatment.In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732Article in journal (Other academic)
  • 23.
    Plaza, Elzbieta
    et al.
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Trela, Jozef
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Hultman, B.
    Impact of seeding with nitrifying bacteria on nitrification process efficiency2001In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 43, no 1, p. 155-163Article in journal (Refereed)
    Abstract [en]

    Seeding of nitrifying bacteria into the activated sludge process was studied both theoretically and experimentally. A simple model was developed for prediction of the effects of seeding of nitrifying bacteria from a separate stage into the activated sludge process. The purpose of seeding is to improve the treatment results and the process stability as well as to decrease the volume requirements of the process. Pilot plant studies were carried out at the Uppsala municipal wastewater treatment plant in order to evaluate the effects of seeding. One line was supplied with supernatant from dewatering of digested sludge and the nitrification process gave an activated sludge with a high fraction of nitrifying bacteria, suitable for seeding. The other line was supplied with pre-precipitated wastewater and with the excess sludge from the line treating the supernatant. The experimental results showed that nitrification could be obtained at sludge ages that would otherwise preclude nitrification. Performance relationships for the system developed, based on laboratory and on-line measurements were studied and are presented. The studies show that seeding may decrease the necessary volume needs for a stable nitrification process and that the effects could be predicted by use of a simple model.

  • 24. Ramirez, J. J.
    et al.
    Frostell, Björn
    KTH, Superseded Departments, Environmental Technology and Work Science.
    Galindo, R.
    A systems approach evaluation of sludge management strategies: sludge management in Valparaiso and Aconcagua, Chile2002In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 46, no 05-apr, p. 381-387Article in journal (Refereed)
    Abstract [en]

    In the 5th Region, located in central Chile, infrastructure projects are being implemented in order to increase the capacity to treat and dispose of sewage. In order to analyse the sludge management alternatives the ORWARE model was used. The research project was divided in two stages: in the first stage, the sewage and sludge management strategies to be compared as well as the objectives were established. The management alternatives chosen were for chemical or biological treatment of sewage while for sludge the management alternatives were based on digestion, composting or lime stabilisation. The second stage included simulation and analysis of results. The main conclusions of the work were: if lowest possible emissions is the main objective of sewage treatment, biological treatment should be applied. Regarding pathogen reduction, both chemical precipitation and biological treatment attain an adequate reduction if the treated sewage is to be discharged to the sea. On the other hand, additional disinfection is needed in the case of discharge to rivers. Control at source should be stressed to avoid heavy metals and toxic organic compounds in the sludge.

  • 25. Rosen, B
    et al.
    Morling, Stig
    A systematic approach to optimal upgrading of water and waste water treatment plants1998In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 37, no 9, p. 9-16Article in journal (Refereed)
    Abstract [en]

    Most of the future works in water and waste water treatment systems will involve the upgrading of existing facilities, for better performance and/or higher capacity. For the efficient implementation of any project, an upgrading strategy should be used, based on careful studies of the local conditions and the defined objectives to be reached. The paper presents a systematic approach to upgrading with emphasis on treatment plant extension, without investing in large volumes, by more efficient use of existing facilities, illustrated by some cases. The importance of real competition in obtaining a cost-effective implementation is stressed.

  • 26. Shah, T.
    et al.
    Cederwall, Klas
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Egboka, B.
    Workshop 7b (synthesis): sustainable groundwater management in rural areas2005In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 51, no 8, p. 165-165Article in journal (Refereed)
    Abstract [en]

    Sustainable groundwater management strategies should be based on adequate assessment of the specific resource characteristics and human reliance on these resources. Disturbed groundwater balance reduces safe yield and degrades groundwater quality.

  • 27.
    Somerville, Richard
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Norrström, Ann-Catrine
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Application of two low-cost adsorption media for removal of toxic metals from contaminated water2009In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 60, no 4, p. 935-942Article in journal (Refereed)
    Abstract [en]

    Since the operational costs of commonly used materials for adsorption of toxic metals can be substantial, natural material may be of great interest for treatment applications. Two types of natural material that have shown particular promise are seaweed and seafood waste. In this study, adsorption capacity of Brown seaweed and shrimp shells were compared with a strong acid cation exchange resin (CER). A case study site was used as a reference point and column experiments were designed in a similar manner although at different scale. Each media reduced concentrations of the target metals to levels below defined reference values. If the alternative adsorption media perform as well in the field as the laboratory, the results suggest that the media tested would completely remove the toxic metals in groundwater and runoff water. Seaweed and shrimp shells had stronger affinities for Pb and Cu than CER. However, CER was superior in affinity for Zn, the most weakly bound metal. Moreover, the results showed that Ca in the solution reduced the adsorption capacity of the other metals. This illustrates the limitations of applying the behaviour of the batch studies with single metal solutions to a multi-component system with competitive adsorption.

  • 28.
    Song, Xingqiang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Ravesteijn, W.
    Frostell, Björn
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Wennersten, Ronald
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Managing water resources for sustainable development: the case of integrated river basin management in China2010In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 61, no 2, p. 499-506Article in journal (Refereed)
    Abstract [en]

    The emerging water crisis in China shows that the current institutional frameworks and policies with regard to water resources management are incapable of achieving an effective and satisfactory situation that includes Integrated River Basin Management (IRBM). This paper analyses this framework and related policies, examines their deficiencies in relation to all water stress problems and explores alternatives focusing on river basins. Water resources management reforms in modern China are reviewed and the main problems involved in transforming the current river management system into an IRBM-based system are analysed. The Huai River basin is used as an example of current river basin management, with quantitative data serving to show the scale and scope of the problems in the country as a whole. The institutional reforms required are discussed and a conceptual institutional framework is proposed to facilitate the implementation of IRBM in China. In particular, the roles, power and responsibilities of River Basin Commissions (RBCs) should be legally strengthened; the functions of supervising, decision-making and execution should be separated; and cross-sectoral legislation, institutional coordination and public participation at all levels should be promoted.

  • 29. Stypka, T.
    et al.
    Plaza, Elzbieta
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Stypka, A.
    Trela, Jozef
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Hultman, B.
    Regional planning and product recovery as tools for sustainable sludge management2002In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 46, no 05-apr, p. 389-396Article in journal (Refereed)
    Abstract [en]

    The article presents two aspects of sludge management: regional planning and product recovery. The introduction of these two elements can reduce the cost, close the ecocycle and make the management more sustainable. A spreadsheet program to optimize the regional location of different facilities is presented. The simple example shows the potential of the model. The brief comparison of formal problems concerning sludge disposal in Poland and Sweden is also discussed. Requirements of phosphorus recovery and recycling of phosphorus to the phosphate industry make sludge fractionation in combination with product recovery a new development in wastewater handling. Phosphorus recovery from sludges with chemical bound phosphorus requires complex and expensive process technology and may therefore lead to increased regional sludge management with a central sludge treatment plant.

  • 30.
    Szatkowska, Beata
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Cema, Grzegorz
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Płaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Hultman, Bengt
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    A one-stage system with partial nitritation and Anammox processes in the moving-bed biofilm reactor2007In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 55, no 8-9, p. 19-26Article in journal (Refereed)
    Abstract [en]

    The ability of bacterial cultures to create biofilm brings a possibility to enhance biological 0 0 wastewater treatment efficiency. Moreover, the ability of Anammox and Nitrosomonas species to grow within the same biofilm layer enabled a one-stage system for nitrogen removal to be designed. Such a system, with Kaldnes rings as carriers for biofilm growth, was tested in a technical pilot plant scale (2.1 m(3)) at the Himmerfjarden Waste Water Treatment Plant (WWTP) in the Stockholm region. The system was directly supplied with supernatant originating from dewatering of digested sludge containing high ammonium concentrations. Nearly 1-year of operational data showed that during the partial nitritation/Anammox process, alkalinity was utilised parallel to ammonium removal. The process resulted in a small pH drop, and to its relationship with conductivity was found. The nitrogen removal rate for the whole period oscillated around 1.5g N m(-2) d(-1) with a maximum value equal to 1.9 g N m(-2) d(-1). Parallel to the pilot plant experiment a series of batch tests were run to investigate the influence on removal rates of different dissolved oxygen 4, conditions and addition of nitrite. The highest nitrogen removal rate (5.2 g N m(-2) d(-1)) in batch tests was obtained when the Anammox process was stimulated by the addition of nitrite. In the simultaneous partial nitritation and Anammox process, the partial nitritation was the rate-limiting step.

  • 31.
    Thunqvist, Eva-Lotta
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Increased chloride concentration in a lake due to deicing salt application2003In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 48, no 9, p. 51-59Article in journal (Refereed)
    Abstract [en]

    During winter, the Swedish National Road Administration uses on average 250,000 tonnes of sodium chloride for deicing purposes. Chloride concentration is a function of the amount of deicing salt applied during the winter season and the amount of water in which the salt can be diluted. An estimation of seasonal amount of deicing salt in relation to amount of run-off was used in order to identify the effects of deicing salt. The measured chloride concentration in a lake used as a municipal water supply was similar to the concentration estimated by a simple steady state method accounting for the catchment area. The simplified steady state method was a useful tool for estimating steady state concentrations on a regional level, including a non-influenced lake as a comparison.

  • 32.
    Trojanowicz, Karol
    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.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. IVL Swedish Environmental Institute, Sweden.
    Pilot scale studies on nitritation-anammox process for mainstream wastewater at low temperature2016In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 73, no 4, p. 761-768Article in journal (Refereed)
    Abstract [en]

    Process of partial nitritation-anammox for mainstream wastewater at low temperature was run in a pilot scale moving bed biofilm reactor (MBBR) system for about 300 days. The biofilm history in the reactor was about 3 years of growth at low temperature (down to 10 degrees C). The goal of the studies presented in this paper was to achieve effective partial nitritation-anammox process. Influence of nitrogen loading rate, hydraulic retention time, aeration strategy (continuous versus intermittent) and sludge recirculation (integrated fixed-film activated sludge (IFAS) mode) on deammonification process' efficiency and microbial activity in the examined system was tested. It was found that the sole intermittent aeration strategy is not a sufficient method for successful suppression of nitrite oxidizing bacteria in MBBR. The best performance of the process was achieved in IFAS mode. The highest recorded capacity of ammonia oxidizing bacteria and anammox bacteria in biofilm was 1.4 gN/m(2)d and 0.5 gN/m(2)d, respectively, reaching 51% in nitrogen removal efficiency.

  • 33. Vinnerås, Björn
    et al.
    Hedenkvist, Mikael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nordin, Annika
    Wilhelmson, Anders
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Peepoo bag: self-sanitising single use biodegradable toilet2009In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 59, no 9, p. 1743-1749Article in journal (Refereed)
    Abstract [en]

    Unsafe water, sanitation and hygiene together with deficient nutritional status are major contributors to the global burden of disease. Safe collection, disposal and reuse of human excreta would enable the risk of transmission of diseases to be decreased and household food security to be increased in many regions. However, the majority of the 2.5 billion people lacking improved sanitation comprise poor people in societies with weak infrastructure. This study developed a low cost sanitation option requiring little investment and maintenance-a single use, self-sanitising, biodegradable toilet (Peepoo bag) and tested it for smell, degradability and hygiene aspects. It was found that no smell was detectable from a 25 mu m thick bag filled with faeces during 24 h in a 10m(2) room at 30 degrees C. Bags that had been in contact with urea-treated faeces or urine for 2 months in air, compost or water at 24 or 37 degrees C showed little signs of degradation. Furthermore, pathogen inactivation modelling of the 4 g of urea present in the bag indicated that appropriate sanitation of faecal material collected is achieved in the bag within 2-4 weeks, after which the bag can be degraded and reused as fertiliser.

  • 34.
    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.

  • 35.
    Yang, Jingjing
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Tjus, Kare
    N2O emissions from a one stage partial nitrification/anammox process in moving bed biofilm reactors2013In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 68, no 1, p. 144-152Article in journal (Refereed)
    Abstract [en]

    Nitrous oxide (N2O) emissions from wastewater treatment are getting increased attention because their global warming potential is around 300 times that of carbon dioxide. The aim of the study was to measure nitrous oxide emissions from one stage partial nitrification/anammox (Anaerobic Ammonium Oxidation) reactors, where nitrogen is removed in a biological way. The first part of the experimental study was focused on the measurements of nitrous oxide emissions from two pilot scale reactors in the long term; one reactor with intermittent aeration at 25 degrees C and the other reactor with continuous aeration at 22-23 degrees C. The second part of the experiment was done to evaluate the influence of different nitrogen loads and aeration strategies, described by the ratio between the non-aerated and aerated phase and the dissolved oxygen concentrations, on nitrous oxide emissions from the process. The study showed that 0.4-2% of the nitrogen load was converted into nitrous oxide from two reactors. With higher nitrogen load, the amount of nitrous oxide emission was also higher. A larger fraction of nitrous oxide was emitted to the gas phase while less was emitted with the liquid effluent. It was also found that nitrous oxide emissions were similar under intermittent and continuous aeration.

  • 36.
    Zubrowska-Sudol, Monika
    et al.
    Department of Environment Engineering, Warsaw University of Technology, Warsaw, Poland.
    Yang, Jingjing
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Evaluation of deammonification process performance at different aeration strategies2011In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 63, no 6, p. 1168-1176Article in journal (Refereed)
    Abstract [en]

    In a deammonification process applied in the moving bed biofilm reactor (MBBR) oxygen is a crucial parameter for the process performance and efficiency. The objective of this study was to investigate different aeration strategies, characterised by the ratio between non-aerated and aerated phase times (R) and dissolved oxygen concentrations (DO). The series of batch tests were conducted with variable DO concentrations (2, 3, 4 mg L-1) and R values (0-continuous aeration; 1/3, 1, 3-intermittent aeration) but with the same initial ammonium concentration, volume of the moving bed and temperature. It was found that the impact of DO on deammonification was dependent on the R value. At R=0 and R=1/3, an increase of DO caused a significant increase in nitrogen removal rate, whereas for R=1 and R=3 similar rates of the process were observed irrespectively of the DO. The highest nitrogen removal rate of 3.33 g N m(-2) d(-1) (efficiency equal to 69.5%) was obtained at R=1/3 and DO=4 mg L-1. Significantly lower nitrogen removal rates (1.17-1.58 g N m(-2) d(-1)) were observed at R=1 and R=3 for each examined DO. It was a consequence reduced aerated phase duration times and lesser amounts of residual nitrite in non-aerated phases as compared to R 1/3.

1 - 36 of 36
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