Skip to main content

LUP Student Papers

LUND UNIVERSITY LIBRARIES

Nitrification performance in a novel biofilm process based on external biofilm growth : Effects of carrier surface area and substrate limitations

Zellmer, Ronja LU (2024) VVAM01 20241
Chemical Engineering (M.Sc.Eng.)
Abstract
An increasing usage of ammonium through societal and industrial development is threatening
the water bodies around the world. To protect the aquatic ecosystem and drinking water
resources, ammonium can be removed with biological treatment at wastewater treatment
plants (WWTP). The development of WWTPs in the last century is aiming to implement
solutions, which are cost and energy efficient, have a small footprint and combine a high
removal rate of as many substances as possible. A majority of those requirements can be
achieved by implementing biofilm-based biological processes, where the microorganisms
grow as biofilms on installed supporting material inside the reactors.
One example of a biofilm process is the Moving Bed Biofilm... (More)
An increasing usage of ammonium through societal and industrial development is threatening
the water bodies around the world. To protect the aquatic ecosystem and drinking water
resources, ammonium can be removed with biological treatment at wastewater treatment
plants (WWTP). The development of WWTPs in the last century is aiming to implement
solutions, which are cost and energy efficient, have a small footprint and combine a high
removal rate of as many substances as possible. A majority of those requirements can be
achieved by implementing biofilm-based biological processes, where the microorganisms
grow as biofilms on installed supporting material inside the reactors.
One example of a biofilm process is the Moving Bed Biofilm Reactor (MBBR), in which the
supporting material comes in the form of carriers with a large protected surface area for
biofilm to grow on. The fact that the growing area for the biofilm is limited to the inner
surface of the carriers is a potential drawback for MBBRs.
A recent development in biofilm process technologies is the AnoxKaldnes CellaTM technology
(by Veolia Water Technologies). Cella is a biofilm process similar to the MBBR, in which
biofilm is retained on suspended material in the reactors. However, in Cella the support
material are irregular particles based on stabilized, recycled biomass. In Cella, the biofilm will
grow on the outside of the support material. This results in a more exposed biofilm area,
which will increase with increasing biofilm thickness, in contrast to conventional MBBR
carriers.
To better understand how this new biofilm process behaves and differs from the MBBR, the
Cella technology is compared to the conventional MBBR technology, by studying the effect
of various operation parameters on nitrification performance in a bench-scale lab system.
The overall reactor performance showed earlier biofilm development in the MBBR but a
larger nitrification potential of the Cella reactors, independently of their initial fill rate of 3%,
6% and 9%. The performed cycle studies showed an increase in nitrification rate of 26-36%
at 20°C and of 40% at 15°C. In addition, effluent concentrations reached with the Cella
reactors can be lower than with MBBR even under higher loads. Furthermore, by performing
activity studies at different oxygen levels, it was shown that the nitrification rate depends on
the oxygen levels in the reactor as well as the oxygen levels the biofilm in the Cella system is
adapted to. The maximum nitrification rate of the Cella was not found due to the high
flexibility of the biofilm. This results in an adjustment of the biofilm to the given conditions.
Hence, implementing the Cella technology allows a reduction of the ammonium loads in
wastewater. It can also be used to extend the existing reduction to meet the new standards of
the EU- urban wastewater treatment directive. (Less)
Abstract (Swedish)
En ökande användning av ammonium genom samhälls- och industriell utveckling hotar
utvatten runt om i världen. För att skydda det akvatiska ekosystemet och
dricksvattenresurserna kan ammonium avlägsnas med biologisk behandling vid
avloppsreningsverk. Utvecklingen av avloppsreningsverk under det senaste århundradet syftar
till att implementera lösningar som är kostnads- och energieffektiva, har en liten fotavtryck
och kombinerar en hög avlägsnande grad av så många ämnen som möjligt. En majoritet av
dessa krav kan uppnås genom att implementera biofilmsbaserade biologiska processer, där
mikroorganismer växer som biofilmer på installerat stödmateriel inuti reaktorer.
Ett exempel på en biofilmprocess är Moving Bed Biofilm Reactor (MBBR),... (More)
En ökande användning av ammonium genom samhälls- och industriell utveckling hotar
utvatten runt om i världen. För att skydda det akvatiska ekosystemet och
dricksvattenresurserna kan ammonium avlägsnas med biologisk behandling vid
avloppsreningsverk. Utvecklingen av avloppsreningsverk under det senaste århundradet syftar
till att implementera lösningar som är kostnads- och energieffektiva, har en liten fotavtryck
och kombinerar en hög avlägsnande grad av så många ämnen som möjligt. En majoritet av
dessa krav kan uppnås genom att implementera biofilmsbaserade biologiska processer, där
mikroorganismer växer som biofilmer på installerat stödmateriel inuti reaktorer.
Ett exempel på en biofilmprocess är Moving Bed Biofilm Reactor (MBBR), där
stödmaterialet kommer i form av bärare med en stor skyddad yta för biofilm att växa på. Det
faktum att växande området för biofilmen är begränsat till den inre ytan av bärarna är en
potentiell nackdel för MBBR.
En nyare utveckling inom teknik för biofilmprocesser är AnoxKaldnes CellaTM-teknologin (av
Veolia Water Technologies). Cella är en biofilmprocess liknande MBBR, där biofilmen
behålls på suspenderat material i reaktorerna. Men i Cella är stödmaterialet oregelbundna
partiklar baserade på stabiliserat, återvunnet biomassa. I Cella kommer biofilmen att växa på
utsidan av stödmaterialet. Detta resulterar i en mer exponerad biofilmområde, vilket ökar med
ökad biofilmens tjocklek, till skillnad från konventionella MBBR-bärare.
För att bättre förstå hur denna nya biofilmprocess beter sig och skiljer sig från MBBR,
jämförs Cella-teknologin med den konventionella MBBR-teknologin genom att studera
effekten av olika driftsparametrar på nitrifieringsprestanda i ett bänkskala laboratorie system.
Den övergripande reaktorprestandan visade tidigare biofilmutveckling i MBBR men en större
nitrifieringspotential för Cella-reaktorerna, oberoende av deras initiala fyllnadsgrad på 3%,
6% och 9%. De utförda cykelstudierna visade en ökning av nitrifieringshastigheten med
26-36% vid 20°C och med 40% vid 15°C. Dessutom kan utlopps koncentrationerna som
uppnås med Cella-reaktorerna vara lägre än med MBBR även under högre belastningar.
Vidare visades det genom att utföra aktivitetsstudier vid olika syrgasnivåer att
nitrifieringshastigheten beror på syrgasnivåerna i reaktorn samt syrgasnivåerna som biofilmen
i Cella-systemet är anpassad till. Den maximala nitrifieringshastigheten för Cella hittades inte
på grund av biofilmens höga flexibilitet. Detta resulterar i en justering av biofilmen till de
givna förhållandena. Således möjliggör implementeringen av Cella-teknologin en minskning
av ammoniumbelastningen i avloppsvattnet. Den kan också användas för att förlänga den
befintliga minskningen för att uppfylla de nya standarderna för EU: s direktiv om behandling
av stadsavloppsvatten. (Less)
Popular Abstract
Refining wastewater treatment: Unveiling the power of external biofilm growth.
Refining the biofilm process in wastewater treatment, showed that external growth of the
biofilm gave a distinct nitrification advantage, independent of changes in temperature, oxygen
dynamics and loads.
In the field of environmental sustainability, wastewater treatment stands as a crucial frontier,
safeguarding our aquatic ecosystems from the threats of pollution. As urban spaces expand,
the demand for efficient wastewater treatment solutions intensifies. In wastewater treatment,
microbes are used to remove pollutants from the wastewater. They are growing as slime in the
water and feed on the remains from faeces and other things transporter in the... (More)
Refining wastewater treatment: Unveiling the power of external biofilm growth.
Refining the biofilm process in wastewater treatment, showed that external growth of the
biofilm gave a distinct nitrification advantage, independent of changes in temperature, oxygen
dynamics and loads.
In the field of environmental sustainability, wastewater treatment stands as a crucial frontier,
safeguarding our aquatic ecosystems from the threats of pollution. As urban spaces expand,
the demand for efficient wastewater treatment solutions intensifies. In wastewater treatment,
microbes are used to remove pollutants from the wastewater. They are growing as slime in the
water and feed on the remains from faeces and other things transporter in the wastewater. This
slime is called biofilm. Biofilm processes in wastewater treatment are using pipe bits to
increase the surface for biofilm growth on. The biofilm only grows on the inside, where it
does not get rubbed off. Hence, implementing biofilm processes, offering compact and
effective treatment options with the possibility to treat large loads of water, but at the same
time their space for biofilm growth is limited.
Resent developments allowed external biofilm growth in a novel biofilm technology using
pebbles to increase the surface for biofilm to grow on. Allowing biofilm to grow to an
unlimited extent, building up on its own previous built structure. In this study, we investigated
the microbial activity comparing the novel biofilm technology to a conventional biofilm
technology. Over 421 days of experimentation, it was shown that the microbial activity of the
novel biofilm technology was constantly higher than in the conventional biofilm technology.
Revealing a remarkable increase of microbial activity with up to 40%. The higher activity also
led to lower values of pollutants in the effluent water, independent of the pollutant load put
onto the system.
Despite fluctuations in biofilm thickness, the novel biofilm system demonstrated robust
performance, achieving efficient pollutant removal even under changing conditions.
Surprisingly, the flexibility of the biofilm in the novel biofilm technology was so high, that it
was able to adapt to whatever conditions it is put into. Even loss of pebbles were compensated
in the shortest time and did not affect the microbial activity negatively.
In summary, the study suggests that the novel biofilm technology could potentially improve
wastewater treatment permanently, offering a promising solution to the evolving challenges of
wastewater treatment in an increasingly urbanized world. By using the potential of external
biofilm growth, microbial activity can be enhanced, leading to lower pollutants levels
reaching nature and economize wastewater treatment in the future. (Less)
Please use this url to cite or link to this publication:
author
Zellmer, Ronja LU
supervisor
organization
course
VVAM01 20241
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Nitrification, Wastewater treatment, Biofilm processes, Cella technology, Water and environmental engineering
language
English
id
9151720
date added to LUP
2024-05-20 08:39:10
date last changed
2024-05-20 08:39:10
@misc{9151720,
  abstract     = {{An increasing usage of ammonium through societal and industrial development is threatening
the water bodies around the world. To protect the aquatic ecosystem and drinking water
resources, ammonium can be removed with biological treatment at wastewater treatment
plants (WWTP). The development of WWTPs in the last century is aiming to implement
solutions, which are cost and energy efficient, have a small footprint and combine a high
removal rate of as many substances as possible. A majority of those requirements can be
achieved by implementing biofilm-based biological processes, where the microorganisms
grow as biofilms on installed supporting material inside the reactors.
One example of a biofilm process is the Moving Bed Biofilm Reactor (MBBR), in which the
supporting material comes in the form of carriers with a large protected surface area for
biofilm to grow on. The fact that the growing area for the biofilm is limited to the inner
surface of the carriers is a potential drawback for MBBRs.
A recent development in biofilm process technologies is the AnoxKaldnes CellaTM technology
(by Veolia Water Technologies). Cella is a biofilm process similar to the MBBR, in which
biofilm is retained on suspended material in the reactors. However, in Cella the support
material are irregular particles based on stabilized, recycled biomass. In Cella, the biofilm will
grow on the outside of the support material. This results in a more exposed biofilm area,
which will increase with increasing biofilm thickness, in contrast to conventional MBBR
carriers.
To better understand how this new biofilm process behaves and differs from the MBBR, the
Cella technology is compared to the conventional MBBR technology, by studying the effect
of various operation parameters on nitrification performance in a bench-scale lab system.
The overall reactor performance showed earlier biofilm development in the MBBR but a
larger nitrification potential of the Cella reactors, independently of their initial fill rate of 3%,
6% and 9%. The performed cycle studies showed an increase in nitrification rate of 26-36%
at 20°C and of 40% at 15°C. In addition, effluent concentrations reached with the Cella
reactors can be lower than with MBBR even under higher loads. Furthermore, by performing
activity studies at different oxygen levels, it was shown that the nitrification rate depends on
the oxygen levels in the reactor as well as the oxygen levels the biofilm in the Cella system is
adapted to. The maximum nitrification rate of the Cella was not found due to the high
flexibility of the biofilm. This results in an adjustment of the biofilm to the given conditions.
Hence, implementing the Cella technology allows a reduction of the ammonium loads in
wastewater. It can also be used to extend the existing reduction to meet the new standards of
the EU- urban wastewater treatment directive.}},
  author       = {{Zellmer, Ronja}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Nitrification performance in a novel biofilm process based on external biofilm growth : Effects of carrier surface area and substrate limitations}},
  year         = {{2024}},
}