Microsensor determination of multiple microbial processes in an oxygen-based membrane aerated biofilm

2013 ◽  
Vol 69 (5) ◽  
pp. 909-914 ◽  
Author(s):  
Shuying Tan ◽  
Tong Yu ◽  
Han-chang Shi
Keyword(s):  
Sulfate Reduction ◽  
Nitrogen Removal ◽  
Biofilm Reactor ◽  
Bulk Liquid ◽  
Simultaneous Occurrence ◽  
Anoxic Zone ◽  
Oxidation Activity ◽  
Production And Consumption ◽  
Consumption Rates

Microsensor techniques were used to investigate in situ the simultaneous occurrence of sulfate reduction and nitrogen removal in a membrane aerated biofilm reactor. H2S, O2, pH, ORP, NH4+ and NO3− microsensors were fabricated and used to measure the profiles inside the membrane aerated biofilm. Production and consumption rates of H2S, O2, NH4+ and NO3− were estimated using corresponding concentration profiles. The results showed that in anoxic zone, located from the interface between biofilm and bulk liquid to about 550 μm below the interface, both sulfate reduction and denitrification occurred. Highest H2S production rates (around 0.27 mg L−1s−1) were found about 400 to 450 μm below the interface. Below the anoxic zone, an aerobic zone was present. High H2S oxidation activity occurred at around 550–700 μm below the interface. High oxygen consumption rates (0.34 mg L−1s−1) occurred at around 750–900 μm below the interface. Nitrification activity occurred at about 500–650 μm below the interface. Along the entire biofilm depth, pH changed slightly (within 0.2 unit). Near the interface of the aerobic and anoxic zone, there was a drastic redox potential change. These results demonstrated simultaneous sulfate reduction and nitrogen removal in a piece of membrane aerated biofilm.

Extracellular polymeric substances in relation to nutrient removal from a sequencing batch biofilm reactor

2001 ◽  
Vol 43 (6) ◽  
pp. 185-192 ◽  
Author(s):  
E. Choi ◽  
Z. Yun ◽  
Y. Park ◽  
H. Lee ◽  
H. Jeong ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Biofilm Reactor ◽  
Bulk Liquid ◽  
Growth Media ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Biofilm Growth ◽  
Biological Nitrogen

Experimental investigations were performed to determine the possibility of simultaneous biological nitrogen and phosphorus removal during various biofilm processes in conjunction with biofilm characterisation, especially extracellular polymeric substance (EPS). Since biological nitrogen removal requires an alternating exposure of anaerobic-anoxic-oxic conditions in the bulk liquid that surrounds the biofilm growth media, a sequencing batch reactor (SBR)-type operation was used. Various materials including expanded clay, polystyrene, polyurethane, and acrylic materials were used as the biofilm growth support medium. Simultaneous nitrogen and phosphorus removal was possible with SBR, but it was postulated that nutrient removal efficiencies varied with film thickness. Thinner biofilm promoted nitrification and phosphorus removal, but thicker biofilm enhanced denitrification and reduced phosphorus removal. EPS contents were similar regardless of support media types or biofilm configuration, but EPS contents gradually increased as the film growth continued after backwashing. EPS contents were increased with increased nitrogen removal, but it was difficult to define its relation with phosphorus removal. In addition, suspended solids removal was correlated well with the EPS content in the biofilms.

Effect of draft tube diameter on nitrogen removal from domestic sewage in a draft tube type reactor

1998 ◽  
Vol 38 (1) ◽  
pp. 319-326
Author(s):  
Taku Fujiwara ◽  
Iso Somiya ◽  
Hiroshi Tsuno ◽  
Yoshio Okuno
Keyword(s):  
Flow Rate ◽  
Nitrogen Removal ◽  
Draft Tube ◽  
Domestic Sewage ◽  
Tube Diameter ◽  
Continuous Treatment ◽  
Anoxic Zone ◽  
Type Reactor ◽  
Tube Type ◽  
Volumetric Loading

The effect of the ratio of draft tube diameter to reactor diameter (Di/Do) on the efficiency of nitrogen removal from domestic sewage is discussed based on liquid-circulating flow rate and continuous treatment data. More than 2.5 minutes of circulation time in the annulus part, which is required to create an anoxic zone, could be maintained under operating conditions in which air flow rate per reactor volume was 2 m3/(m3 · hr) and Di/Do was 0.19. When Di/Do was set at 0.19, the average total organic carbon (TOC), total nitrogen (TN) and dissolved nitrogen (DN) removal efficiencies were 83.2%, 72.1% and 71.6%, respectively, which were higher than those when Di/Do was at 0.26 or 0.36. From these results, it is concluded that 0.19 is the best Di/Do for nitrogen removal in a draft-tube type reactor with an effective depth of 4.0m under the treatment condition in which the BOD volumetric loading rate is in the range 0.22 to 0.46 kgBOD/(m3 · day). More than 80% nitrification and denitrification efficiencies can be achieved simultaneously when both conditions, the aerobic zone ratio being more than 0.2, and the anoxic zone ratio being more than 0.3, are satisfied.

Development of a Flow-through Biofilm Reactor for Anammox Startup and Operation: Nitrogen Removal and Metacommunity

2021 ◽  
Author(s):  
Chao Jin ◽  
Jiali Xing ◽  
Zijian Chen ◽  
Yabing Meng ◽  
Fuqiang Fan ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Biofilm Reactor ◽  
Flow Through

scholarly journals Microbial N2O consumption in and above marine N2O production hotspots

2020 ◽  
Author(s):  
Xin Sun ◽  
Amal Jayakumar ◽  
John C. Tracey ◽  
Elizabeth Wallace ◽  
Colette L. Kelly ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Substrate Affinity ◽  
N2o Production ◽  
Anoxic Waters ◽  
Production And Consumption ◽  
Consumption Rates ◽  
Anoxic Zones ◽  
First Time ◽  
Microbial N

AbstractThe ocean is a net source of N2O, a potent greenhouse gas and ozone-depleting agent. However, the removal of N2O via microbial N2O consumption is poorly constrained and rate measurements have been restricted to anoxic waters. Here we expand N2O consumption measurements from anoxic zones to the sharp oxygen gradient above them, and experimentally determine kinetic parameters in both oxic and anoxic seawater for the first time. We find that the substrate affinity, O2 tolerance, and community composition of N2O-consuming microbes in oxic waters differ from those in the underlying anoxic layers. Kinetic parameters determined here are used to model in situ N2O production and consumption rates. Estimated in situ rates differ from measured rates, confirming the necessity to consider kinetics when predicting N2O cycling. Microbes from the oxic layer consume N2O under anoxic conditions at a much faster rate than microbes from anoxic zones. These experimental results are in keeping with model results which indicate that N2O consumption likely takes place above the oxygen deficient zone (ODZ). Thus, the dynamic layer with steep O2 and N2O gradients right above the ODZ is a previously ignored potential gatekeeper of N2O and should be accounted for in the marine N2O budget.

scholarly journals Black Tea Source, Production, and Consumption: Assessment of Health Risks of Fluoride Intake in New Zealand

2017 ◽  
Vol 2017 ◽  
pp. 1-27 ◽  
Author(s):  
Declan T. Waugh ◽  
Michael Godfrey ◽  
Hardy Limeback ◽  
William Potter
Keyword(s):  
New Zealand ◽  
Black Tea ◽  
Fluoride Content ◽  
The Public ◽  
Fluoride Intake ◽  
Production And Consumption ◽  
Tea Infusions ◽  
High Prevalence ◽  
Consumption Rates ◽  
Fluoride Ion Selective Electrode

In countries with fluoridation of public water, it is imperative to determine other dietary sources of fluoride intake to reduce the public health risk of chronic exposure. New Zealand has one of the highest per capita consumption rates of black tea internationally and is one of the few countries to artificially fluoridate public water; yet no information is available to consumers on the fluoride levels in tea products. In this study, we determined the contribution of black tea as a source of dietary fluoride intake by measuring the fluoride content in 18 brands of commercially available products in New Zealand. Fluoride concentrations were measured by potentiometric method with a fluoride ion-selective electrode and the contribution of black tea to Adequate Intake (AI) and Tolerable Upper Intake Level (UL) was calculated for a range of consumption scenarios. We examined factors that influence the fluoride content in manufactured tea and tea infusions, as well as temporal changes in fluoride exposure from black tea. We review the international evidence regarding chronic fluoride intake and its association with chronic pain, arthritic disease, and musculoskeletal disorders and provide insights into possible association between fluoride intake and the high prevalence of these disorders in New Zealand.

Nitrogen removal from livestock and poultry breeding wastewaters using a novel sequencing batch biofilm reactor

2010 ◽  
Vol 62 (11) ◽  
pp. 2599-2606 ◽  
Author(s):  
Hong Xiao ◽  
Ping Yang ◽  
Hong Peng ◽  
Yanzong Zhang ◽  
Shihuai Deng ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Heterotrophic Bacteria ◽  
Biofilm Reactor ◽  
N Accumulation ◽  
Sequencing Batch Biofilm Reactor ◽  
Poultry Breeding ◽  
Mode 2 ◽  
Do Concentration ◽  
Nitrification And Denitrification ◽  
Biological Nitrogen

A study was conducted regarding the biological nitrogen removal from the livestock and poultry breeding wastewater (LPBWs) using a novel sequencing batch biofilm reactor (SBBR). Nitrogen removal process was studied under three aeration strategies/modes, referred to as MODE 1, 2, and 3. The results showed that MODE 2 (one operation period: instant fill of LPBWs, 3.0 h aeration, 1.5 h non-aeration, 1.5 h aeration, 1.0 h non-aeration and rapid drain of treated LPBWs) performed the best in nitrogen removal. Under MODE 2, the removal efficiencies were as high as 96.1 and 92.1% for NH3-N and TN, respectively. Simultaneous nitrification and denitrification (SND), as well as shortcut nitrification and denitrification are likely to be the two main mechanisms for the nitrogen removal in this study. Nitrifying bateria were not inhibited by heterotrophic bacteria with C/N ratios ranging from 18.1 to 21.4 and DO concentration of 2.0 mg/l. Alternation between aeration and non-aeration played an important role in NO2−-N accumulation.

scholarly journals Biofilm carrier migration model describes reactor performance

2017 ◽  
Vol 75 (12) ◽  
pp. 2818-2828 ◽  
Author(s):  
Joshua P. Boltz ◽  
Bruce R. Johnson ◽  
Imre Takács ◽  
Glen T. Daigger ◽  
Eberhard Morgenroth ◽  
...  
Keyword(s):  
Plug Flow ◽  
Biofilm Reactor ◽  
Bulk Liquid ◽  
Reactor Performance ◽  
Reactor Model ◽  
Operational Conditions ◽  
Limit Model ◽  
Biofilm Model ◽  
Reactor Models ◽  
The Impact

The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved mathematical description of the biofilm reactor and its components. Existing biofilm reactor models typically include a one-dimensional biofilm model, a process (biokinetic and stoichiometric) model, and a continuous flow stirred tank reactor (CFSTR) mass balance that [when organizing CFSTRs in series] creates a pseudo two-dimensional (2-D) model of bulk-liquid hydrodynamics approaching plug flow. In such a biofilm reactor model, the user-defined biofilm area is specified for each CFSTR; thereby, Xcarrier does not exit the boundaries of the CFSTR to which they are assigned or exchange boundaries with other CFSTRs in the series. The error introduced by this pseudo 2-D biofilm reactor modeling approach may adversely affect model results and limit model-user capacity to accurately calibrate a model. This paper presents a new sub-model that describes the migration of Xcarrier and associated biofilms, and evaluates the impact that Xcarrier migration and axial dispersion has on simulated system performance. Relevance of the new biofilm reactor model to engineering situations is discussed by applying it to known biofilm reactor types and operational conditions.

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