Modeling dynamics of organic carbon and nitrogen removal during aeration interruption in aerated horizontal flow treatment wetlands

Abstract Despite recent developments in process-based modeling of treatment wetlands (TW), the dynamic response of horizontal flow (HF) aerated wetlands to interruptions of aeration has not yet been modeled. In this study, the dynamic response of organic carbon and nitrogen removal to interruptions of aeration in an HF aerated wetland was investigated using a recently-developed numerical process-based model. Model calibration and validation were achieved using previously obtained data from pilot-scale experiments. Setting initial concentrations for anaerobic bacteria to high values ( 35–70 mg L−1) and including ammonia sorption was important to simulate the treatment performance of the experimental wetland in transition phases when aeration was switched off and on again. Even though steady-state air flow rate impacted steady-state soluble chemical oxygen demand (CODs), ammonia nitrogen (NH4–N) and oxidized nitrogen (NOx–N) concentration length profiles, it did not substantially affect corresponding effluent concentrations during aeration interruption. When comparing simulated with experimental results, it is most likely that extending the model to include mass transfer through the biofilm will allow to better explain the underlying experiments and to increase simulation accuracy. This study provides insights into the dynamic behavior of HF aerated wetlands and discusses assumptions and limitations of the modeling approach.

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Organic Carbon and Nitrogen Removal in Attached-Growth Circulating Reactor (AGCR)

Water Science & Technology ◽

10.2166/wst.1990.0199 ◽

1990 ◽

Vol 22 (3-4) ◽

pp. 179-186 ◽

Cited By ~ 10

Author(s):

S. Karnchanawong ◽

C. Polprasert

Keyword(s):

Organic Carbon ◽

Nitrogen Removal ◽

Loading Rate ◽

Oxygen Demand ◽

Channel Length ◽

Synthetic Wastewater ◽

Attached Growth ◽

Carbon And Nitrogen ◽

Loading Rates ◽

Air Diffusion

Experiments on attached-growth circulating reactor (AGCR) were conducted to investigate its efficiencies on organic carbon and nitrogen removal (through denitrification). A laboratory-scale AGCR, made of serpentine channel with a total length of 180.0 m, was fed with a synthetic wastewater at the chemical oxygen demand (COD) and total nitrogen (TN) loading rates of 3.56-10.16 and 0.30 - 0.91 g/(m2.d), respectively. The reactor effluent was recycled back to the influent feeding point and the dissolved oxygen (DO) concentrations along the channel length were controlled by means of air diffusion. It was found that the COD loading rate of 5 g/(m2. d) corresponding to the TN loading rate of 0.54 g/(m2.d) gave the optimal COD and TN removal rates of 4.8 and 0.43 g/(m2.d), respectively. The overall AGCR performance was limited by the nitrification efficiency at the high TN loading rates. The biofilm accumulation and thickness were found to be relatively high in the first-half portion of the channel length where carbon oxidation and denitrification were predominant. The second-half portion where nitrification mainly occurred had much less biofilm accumulation and thickness.

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Organic carbon and nitrogen removal from a strong wastewater using a denitrifying suspended growth reactor and a horizontal-flow biofilm reactor

Bioresource Technology ◽

10.1016/j.biortech.2006.04.015 ◽

2007 ◽

Vol 98 (4) ◽

pp. 739-744 ◽

Cited By ~ 21

Author(s):

L XIAO ◽

M RODGERS ◽

J MULQUEEN

Keyword(s):

Organic Carbon ◽

Nitrogen Removal ◽

Biofilm Reactor ◽

Horizontal Flow ◽

Carbon And Nitrogen ◽

Suspended Growth

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Evaluation of sequencing batch bioreactor followed by media filtration for organic carbon and nitrogen removal in produced water

Journal of Water Process Engineering ◽

10.1016/j.jwpe.2020.101863 ◽

2021 ◽

Vol 40 ◽

pp. 101863

Author(s):

Emily R. Nicholas ◽

Tzahi Y. Cath

Keyword(s):

Organic Carbon ◽

Nitrogen Removal ◽

Produced Water ◽

Carbon And Nitrogen ◽

Batch Bioreactor

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Combined organic carbon and complete nitrogen removal using anaerobic and aerobic upflow filters

Water Science & Technology ◽

10.2166/wst.1994.0629 ◽

1994 ◽

Vol 30 (12) ◽

pp. 297-306 ◽

Cited By ~ 31

Author(s):

Joseph Akunna ◽

Claude Bizeau ◽

René Moletta ◽

Nicolas Bernet ◽

Alain Héduit

Keyword(s):

Organic Carbon ◽

Removal Efficiency ◽

Nitrogen Removal ◽

Nitrogen Loss ◽

Ammonia Nitrogen ◽

Cod Removal ◽

Cod Removal Efficiency ◽

Treated Effluent ◽

Treated Effluents ◽

Aerobic And Anaerobic

Two laboratory upflow aerobic and anaerobic filters fed with synthetic wastewaters were used to study firstly the effects of aeration rate on the nitrification of anaerobically pre-treated effluents and secondly the effects of recycle-to-influent ratios on methane production rate, denitrification and nitrification performances of a combined aerobic and anaerobic wastewater treatment process. Nitrification of anaerobically pre-treated effluent was accompanied by aerobic post-treatment for residual COD removal. A comparison of nitrification performances using autotrophic medium and anaerobically pre-treated effluents (containing 1203 mg COD 1−1) with the same ammonia nitrogen concentration of about 300 mg NH4-N 1−1 showed that 3% of added ammonia nitrogen was assimilated by autotrophic nitrifiers during nitrification of the autotrophic medium while up to 30% was assimilated by both nitrifiers and heterotrophs during organic carbon removal and nitrification of anaerobically pre-treated effluent. Furthermore, it was suspected that significant nitrogen loss through denitrification occured in the aerobic filter especially at low aeration rates. In the study of the combined aerobic-anaerobic system, maximum ammonia nitrogen removal of 70% through denitrification was obtained at recycle-to-influent ratios of 4 and 5. COD removal efficiency in the anaerobic filter decreased from 77 to 60% for recycle-to-influent ratios of zero to 5. Overall COD removal efficiency of the entire system was constant at about 99% due to heterotrophic COD removal in the aerobic filter.

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Micro-pressure swirl reactor (MPSR) for efficient COD and nitrogen removal of high-concentration wastewater

Water Science & Technology ◽

10.2166/wst.2020.454 ◽

2020 ◽

Vol 82 (9) ◽

pp. 1795-1807 ◽

Cited By ~ 1

Author(s):

Dejun Bian ◽

Zebing Nie ◽

Fan Wang ◽

Shengshu Ai ◽

Suiyi Zhu ◽

...

Keyword(s):

Removal Efficiency ◽

Nitrogen Removal ◽

Lower Cost ◽

Batch Reactor ◽

Oxygen Demand ◽

Swirl Flow ◽

High Concentration ◽

Internal Circulation ◽

Carbon And Nitrogen ◽

Pressure Swirl

Abstract A micro-pressure swirl reactor (MPSR) was developed for carbon and nitrogen removal of wastewater, in which dissolved oxygen (DO) gradient and internal circulation could be created by setting the aerators along one side of the reactor, and micro-pressure could be realized by sealing most of the top cap and increasing the outlet water level. In this study, velocity and DO distribution in the reactor was measured, removal performance treating high-concentration wastewater was investigated, and the main functional microorganisms were analyzed. The experiment results indicated that there was stable swirl flow and spatial DO gradient in MPSR. Operated in sequencing batch reactor mode, distinct biological environments spatially and temporally were created. Under the average influent condition of chemical oxygen demand (COD) concentration of 2,884 mg/L and total nitrogen (TN) of 184 mg/L, COD removal efficiency and removal loading was 98% and 1.8 kgCOD/(m3·d) respectively, and TN removal efficiency and removal loading reached up to 90% and 0.11 kgTN/(m3·d) respectively. With efficient utilization of DO and simpler configuration for simultaneous nitrification and denitrification, the MPSR has the potential of treating high-concentration wastewater at lower cost.

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Organic Carbon and Nitrogen Removal in a Modified Anoxic/Oxic-Membrane Bioreactor Treating High Strength Wastewater

2008 2nd International Conference on Bioinformatics and Biomedical Engineering ◽

10.1109/icbbe.2008.1161 ◽

2008 ◽

Author(s):

Zhimin Fu ◽

Fenglin Yang ◽

Feifei Zhou ◽

Yuan Xue

Keyword(s):

Organic Carbon ◽

Nitrogen Removal ◽

Membrane Bioreactor ◽

High Strength ◽

Carbon And Nitrogen

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Effect of corn cobs as external carbon sources on nitrogen removal in constructed wetlands treating micro-polluted river water

Water Science & Technology ◽

10.2166/wst.2019.156 ◽

2019 ◽

Vol 79 (9) ◽

pp. 1639-1647 ◽

Cited By ~ 2

Author(s):

Lu-ji Yu ◽

Tao Chen ◽

Yanhong Xu

Keyword(s):

Organic Carbon ◽

River Water ◽

Constructed Wetlands ◽

Carbon Sources ◽

Oxygen Demand ◽

Ammonia Nitrogen ◽

Flow Mode ◽

Low Carbon ◽

Polluted River ◽

Corn Cobs

Abstract Micro-polluted river water is characterized as having limited biodegradability, low carbon to nitrogen ratio and little organic carbon supply, all of which makes it hard to further purify. Two bench scale constructed wetlands (CWs) with a horizontal subsurface flow mode were set up in the laboratory to evaluate their feasibility and efficiency on denitrification with and without corn cobs as external carbon sources. Micro-polluted river water was used as feed solution. The CW without corn cobs substrates possessed a good performance in removing chemical oxygen demand (COD, <40 mg/L) and ammonia nitrogen (NH3-N, <0.65 mg/L), but less efficiency in removing total nitrogen (TN) and nitrate nitrogen (NO3-N). In marked contrast, the CW with 1% (w/w) corn cobs substrates as external carbon sources achieved a significant improvement in the removal efficiency of TN (increased from 34.2% to 71.9%) and NO3-N (increased from 19% to 71.9%). The incorporation of corn cobs substrates did not cause any obvious increase in the concentrations of COD and NH3-N in the effluent. This improvement in the denitrification efficiency was owing to the released organic carbon from corn cobs substrates, which facilitated the growth of abundant microbes on the surface and pores of the substrate. The open area of the used corn chips is larger than that of the pristine ones, and corn cobs can continue to provide a carbon fiber source for denitrification.

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Reactive transport modeling of an innovative nature-based solution for domestic sewage treatment

10.5194/egusphere-egu2020-22563 ◽

2020 ◽

Author(s):

Johannes Boog ◽

Thomas Kalbacher ◽

Jaime Nivala ◽

Manfred van Afferden ◽

Roland A. Müller

Keyword(s):

Organic Carbon ◽

Reactive Transport ◽

Developed Countries ◽

Domestic Sewage ◽

Urban Environments ◽

Surface Flow ◽

Aerobic Biodegradation ◽

Horizontal Flow ◽

Sustainable Urban Development ◽

Carbon And Nitrogen

The discharge of inadequately treated sewage is still a worldwide problem that contributes to the deterioration of receiving water bodies. Especially in urban environments of less developed countries this threatens drinking water availability and, therefore, puts human health at risk and impedes sustainable urban development. Aerated treatment wetlands are innovative nature-based solutions that have been successfully applied in treating domestic, municipal and industrial effluents. The advantage of these technologies is their simplicity which translates into low operation and maintenance requirements and robust treatment. Aerated wetlands can be easily integrated into&#160; decentralized water infrastructure to serve the demand of changing and fast-growing urban environments.Aerated wetlands mimic natural processes to treat wastewater. Air is injected into these systems to provide an aerobic environment for increased aerobic biodegradation of pollutants. However, quantitative knowledge on how aeration governs oxygen transfer, organic matter and nitrogen removal within aerated wetlands is still insufficient.In this study, we developed a reactive transport model for horizontal sub-surface flow aerated wetlands using the open-source multi-physics simulator OpenGeoSys. The model was calibrated and validated by pilot-scale experiments with real domestic sewage including steady-state operation and induced aeration failures. In both cases, the model achieved an acceptable degree of simulation accuracy. Furthermore, the experiments including short&#8212;term aeration failure showed that horizontal flow aerated wetlands can fully recover from such operational disruptions.We then analyzed several simulation scenarios and found out that increasing aeration alters and shifts water quality gradients for organic carbon and nitrogen downstream. This can, for instance, be exploited to provide specific effluent qualities for different demands in an urban environment such as irrigation or groundwater recharge. We identified that the aeration rate required to provide an efficient and robust treatment efficacy for organic carbon and nitrogen of domestic wastewater is 150&#8211;200&#160;L&#160;m2 h1. The developed model can be used by researchers and engineers to support the design of horizontal flow aerated wetlands in the context of applications in urban environments. Furthermore, our research highlights the suitability of horizontal flow aerated wetlands as a resilient treatment technology with potential application for water pollution control in urban environments.

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