The anammox coupled partial-denitrification process in an integrated granular sludge and fixed-biofilm reactor developed for mainstream wastewater treatment: performance and community structure

The membrane aerated biofilm reactor (MABR) is an emerging wastewater treatment technology that can greatly decrease energy requirements for wastewater treatment. It consists of cassettes of air-supplying, hollow-fiber membranes that can retrofit existing activated sludge processes. MABR behavior differs from conventional biofilm processes due to the counter-diffusion of the electron donor (ammonia) and acceptor (oxygen). &#160; Partial nitrification (PN), or partial nitrification Anammox (PNA), can further improve MABR energy efficiency and cost effectiveness.&#160; To achieve this, ammonia oxidizing bacteria (AOB) must outcompete nitrite-oxidizing bacteria (NOB). &#160;High temperatures favor AOB, but it is not feasible to heat the wastewater influent.&#160; However, high-temperature compressed air can be supplied to the membrane lumen, increasing temperatures inside the biofilm without increasing the bulk temperatures. No previous research has addressed temperature gradients in biofilms, which can lead to gradients in&#160; biodegradation kinetics, diffusivities, and O2 solubility. &#160; The objective of this research was to explore the effect of temperature gradients in MABR biofilms, especially with respect to PN. We used a one-dimensional multi-species biofilm model, which considers the MABR physical and biochemical behavior, especially with respect to temperature. The model was implemented using COMSOL Multiphysics. We also used bench-scale experiments to explore the effect of biofilm temperature gradients on MABR nitrification and PN performances and microbial community structure. &#160; Model simulations showed that MABR biofilms exposed to a temperature gradient from 20 &#186;C (biofilm interior) to 10 &#186;C (bulk liquid) had a 60% increase in nitrification rates compared with biofilms at 10 &#186;C. More importantly, the model predicted a complete out competition of NOBs within the biofilm. &#160; Preliminary experimental results confirm a significant (105%) increase in nitrification fluxes with a temperature of 30&#186;C compared to ambient temperatures (20&#186;C). Future experiments will validate the model predicted effects of biofilm temperature gradients on nitrification fluxes and microbial community structure.

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Tannery Wastewater Treatment Using an Upflow Anaerobic Fixed Biofilm Reactor (UAFBR)

Environmental Engineering Science ◽

10.1089/109287503770736104 ◽

2003 ◽

Vol 20 (6) ◽

pp. 587-599 ◽

Cited By ~ 15

Author(s):

Z. Song ◽

C.J. Williams ◽

R.G.J. Edyvean

Keyword(s):

Wastewater Treatment ◽

Biofilm Reactor ◽

Tannery Wastewater ◽

Fixed Biofilm

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Influence of deterministic and stochastic processes on microbial community assembly during aerobic granulation

10.1101/356303 ◽

2018 ◽

Cited By ~ 1

Author(s):

Raquel Liébana ◽

Oskar Modin ◽

Frank Persson ◽

Enikö Szabó ◽

Malte Hermansson ◽

...

Keyword(s):

Community Structure ◽

Microbial Community ◽

Community Assembly ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

Batch Reactors ◽

Community Members ◽

Treatment Performance ◽

Biofilm Process ◽

Microbial Community Assembly

ABSTRACTAerobic granular sludge is an energy efficient and compact biofilm process for wastewater treatment which has received much attention during the last decades and is now being implemented in full-scale. However, the factors involved in microbial community assembly during formation of granules are poorly understood and little is known about the reproducibility in treatment performance and community structure. Here we show that both deterministic and stochastic factors exert a dynamic influence during microbial community assembly into granular sludge. During granulation, the microbial communities in three replicate sequencing batch reactors followed similar successional trajectories of the most abundant taxa and showed similar dynamics in diversity. Deterministic factors dominated the assembly of the most abundant community members as the microbial community transitioned from floccular to granular form. Stochastic factors mostly affected rare members of the communities and caused the microbial community structure to diverge in one of the reactors; however, this did not have an impact on the treatment performance. This demonstrates that the reactor function and the dynamics of the most abundant community members are in fact reproducible during the formation of aerobic granules.

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Magnetic field enhanced denitrification efficiency of immobilized bacterial particles

Water Science & Technology ◽

10.2166/wst.2020.156 ◽

2020 ◽

Vol 81 (3) ◽

pp. 622-629

Author(s):

Liangang Hou ◽

Yang Liu ◽

Sa Fan ◽

Jun Li

Keyword(s):

Magnetic Field ◽

Wastewater Treatment ◽

Community Structure ◽

High Throughput Sequencing ◽

Sequencing Analysis ◽

Immobilized Bacteria ◽

Removal Efficiencies ◽

The Stability ◽

The Magnetic Field ◽

Denitrification Process

Abstract The effect of the magnetic field on denitrification process in immobilized bacteria particles was investigated in this study. The magnetic field could enhance the denitrification efficiency, especially for wastewater with low C/N ratios, and the average removal efficiencies of NO3–-N increased by 6.58%. High-throughput sequencing analysis revealed that the magnetic field had substantial impacts on the stability of microbial community structure and relative abundance in immobilized bacteria particles, which was beneficial for the stability of denitrifying bacteria. Through the research in this paper, we suggest that magnetic field can be used to improve the denitrification performance of immobilized bacteria particles in the wastewater treatment industry.

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