scholarly journals Performance of an autotrophic denitrification process with mixed electron donors and a functional microbial community

2018 ◽  
Vol 19 (2) ◽  
pp. 434-443 ◽  
Author(s):  
Xianxin Luo ◽  
Junfeng Su ◽  
Han Liu ◽  
Tinglin Huang ◽  
Li Wei ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Accumulation Rate ◽  
Nitrate Removal ◽  
Biofilm Reactor ◽  
Electron Donors ◽  
Molar Ratio ◽  
Groundwater Treatment ◽  
N Accumulation ◽  
Nitrate N ◽  
N Removal

Abstract A moving bed biofilm reactor (MBBR) using Mn(II) and Fe(II) as mixed electron donors was designed for nitrate removal. The optimal state, as determined by response surface methodology, was an Fe(II):Mn(II) molar ratio of 0.62, electron donor:electron acceptor molar ratio of 2.62 and hydraulic retention time of 10.88 h. Subsequently, the MBBR was applied to groundwater treatment and demonstrated a final nitrate-N removal efficiency of 99.5% with a nitrite-N accumulation rate of 0.0706 mg-N·L−1·h−1. Furthermore, high-throughput sequencing was employed to characterize bacterial communities in the MBBR. Results showed that the genera of Pseudomonas and Acinetobacter may make a contribution to the nitrate removal.

Performance and microbial community of a novel PVA/iron-carbon (Fe–C) immobilized bioreactor for nitrate removal from groundwater

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Qiong Wen ◽  
Junfeng Su ◽  
Guoqing Li ◽  
Tinglin Huang ◽  
Lei Xue ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
High Throughput Sequencing ◽  
Nitrate Removal ◽  
Sequencing Analysis ◽  
N Accumulation ◽  
N Removal ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio ◽  
Denitrification Bioreactor ◽  
Main Component

Abstract An efficient immobilized denitrification bioreactor functioning under anaerobic conditions was developed by combining bacterial immobilization technology with iron-carbon (Fe–C) particles. The effects of key factors on nitrate (NO3 −–N) removal efficiency were invested, such as the carbon-nitrogen ratio (C/N), pH and hydraulic retention time (HRT). Experimental results show that 100.00% NO3 −–N removal efficiency and a low level of nitrite (NO2 −–N) accumulation less than 0.05 mg L−1 were obtained under the condition of a C/N ratio of 3, pH 7.0 and HRT of 6 h. Meteorological chromatographic analysis showed that the final product of denitrification was mainly nitrogen (N2). The main component of precipitation formed in the bioreactor was characterized as Fe3O4 by X-ray diffraction. High-throughput sequencing analysis indicated that the dominant bacterial class in the Fe–C bioreactor was Gammaproteobacteria, while the dominant genera were Zoogloea and Azospira, the relative abundances of which were as high as 23.25 and 15.43%, respectively.

scholarly journals Mixed electron donor autotrophic denitrification processes for groundwater treatment by immobilized biological filters

2017 ◽  
Vol 17 (6) ◽  
pp. 1673-1681 ◽  
Author(s):  
Jun-feng Su ◽  
Dong-hui Liang ◽  
Ting-lin Huang ◽  
Ting-ting Lian ◽  
Wen-dong Wang
Keyword(s):  
Electron Donor ◽  
Hydraulic Retention Time ◽  
Nitrate Removal ◽  
Electron Donors ◽  
Optimal Conditions ◽  
Groundwater Treatment ◽  
Removal Ratio ◽  
Biological Filter ◽  
Nitrate N ◽  
Biological Filters

Abstract An immobilized biological filter (IBF) using Fe(II) and Mn(II) as mixed electron donors was evaluated for nitrate removal in groundwater. Results of the single factor experiments of strain SZ28 under the conditions of electron donor:electron acceptor ratio (1:2, 1.45:1, 3:1), Fe(II):Mn(II) ratio (1:9, 3:7, 5:5) demonstrated that the highest nitrate removal ratio was 100%, 49.6% (Mn(II)) and 100% (Fe(II)) under the conditions of electron donor:electron acceptor ratio of 3:1, Fe(II):Mn(II) ratio of 5:5. Mn(II) and Fe(II) as electron donor was tested for the effects on denitrification in the IBF reactor. Optimal conditions were obtained at an electron donor:electron acceptor ratio of 2:1, hydraulic retention time of 12 h and Fe(II):Mn(II) ratio of 5:5 with the highest removal ratio of nitrate-N (100%), Mn(II) (50.25%) and Fe(II) (99.2%). Results suggest that the optimal condition obtained from the IBF was feasible.

scholarly journals An Exploration of Seaweed Polysaccharides Stimulating Denitrifying Bacteria for Safer Nitrate Removal

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3390
Author(s):  
Hui Zhang ◽  
Lin Song ◽  
Xiaolin Chen ◽  
Pengcheng Li
Keyword(s):  
Growth Rate ◽  
Bacillus Subtilis ◽  
Nitrate Removal ◽  
Denitrifying Bacteria ◽  
Soil Salinization ◽  
Nitrate Content ◽  
Weak Efficiency ◽  
N Accumulation ◽  
N Removal ◽  
Intensively Managed

Excessive use of nitrogen fertilizer in intensively managed agriculture has resulted in abundant accumulation of nitrate in soil, which limits agriculture sustainability. How to reduce nitrate content is the key to alleviate secondary soil salinization. However, the microorganisms used in soil remediation cause some problems such as weak efficiency and short survival time. In this study, seaweed polysaccharides were used as stimulant to promote the rapid growth and safer nitrate removal of denitrifying bacteria. Firstly, the growth rate and NO3−-N removal capacity of three kinds of denitrifying bacteria, Bacillus subtilis (BS), Pseudomonas stutzeri (PS) and Pseudomonas putida (PP), were compared. The results showed that Bacillus subtilis (BS) had a faster growth rate and stronger nitrate removal ability. We then studied the effects of Enteromorpha linza polysaccharides (EP), carrageenan (CA), and sodium alginate (AL) on growth and denitrification performance of Bacillus subtilis (BS). The results showed that seaweed polysaccharides obviously promoted the growth of Bacillus subtilis (BS), and accelerated the reduction of NO3−-N. More importantly, the increased NH4+-N content could avoid excessive loss of nitrogen, and less NO2−-N accumulation could avoid toxic effects on plants. This new strategy of using denitrifying bacteria for safely remediating secondary soil salinization has a great significance.

Bamboo as Solid Carbon Source for De-Nitrification

2013 ◽  
Vol 807-809 ◽  
pp. 1330-1335
Author(s):  
Yin Mei Wang
Keyword(s):  
Carbon Source ◽  
Solid Phase ◽  
Influencing Factor ◽  
Flow Mode ◽  
Nitrite Accumulation ◽  
N Accumulation ◽  
Nitrate N ◽  
N Removal ◽  
Single Carbon Source ◽  
As Solid Phase

This study was conducted to investigate the efficiency and characteristics of de-nitrification using bamboo as solid phase carbon source in a batch and continuous flow mode. Compared to no solid phase carbon source system, the higher nitrate-N removal efficiency and the less nitrite-N accumulation was observed in a de-nitrification system by using bamboo as solid phase carbon source. The results showed that nitrate-N volumetric load averaged between 2.09 mg/L.h when filamentous bamboo as single carbon source, and mean nitrite-N accumulations was only 0.23 mg as 1 g nitrate-N was removed. Moreover, temperature was an important influencing factor for nitrate-N volumetric load and nitrite accumulation. In addition, refractory organic compounds and nitrate-N can simultaneous remove.

scholarly journals Nitrite Accumulation at Low Copper Concentration in a Submerged Partial Bionitrification Reactor

2021 ◽  
Vol 43 (6) ◽  
pp. 419-427
Author(s):  
Sukru Aslan ◽  
Burhanettin Gurbuz
Keyword(s):  
Loading Rate ◽  
Accumulation Rate ◽  
Removal Rate ◽  
Synthetic Wastewater ◽  
Flow Mode ◽  
Nitrite Accumulation ◽  
N Accumulation ◽  
Operational Conditions ◽  
Support Materials ◽  
N Removal

Objectives : Effects of various Cu2+ concentrations in the synthetic wastewater on nitrite accumulation was investigated in a submerged partial biofilter reactor (SPBNR).Methods : Experiments were carried out at the constant operational conditions (T=35℃; pH=9.0 and DO=2.0 mg O2/L) by varying the concentrations between 5-50 mg Cu2+/L. The SPBNR, which was operated in an upward flow mode, set-up consisted of a cylindrical stainless steel. The support materials filling ratio was about 23% of the total reactor volume. The SPBNR was inoculated with microorganism drawn from a batch experimental biological reactor operated about one month by using the synthetic wastewater composition.Results and Discussion : Before exposure to Cu2+, the highest loading rate of 1.3 g NH4-N/(m2.day) was determined under the operational conditions. Addition of 5 µg Cu2+/L into the waters promoted the activity of organisms and the loading rate achieved to 1.6 g NH4-N/(m2.day). At the control operational condition, the ratio of NO2-N/NOx-N was determined as 0.74, while the ratio increased to 0.78 at the Cu2+ concentration of 5 µg/L.Conclusions : Results indicated that the ammonium oxidizing bacteria (AOB) is more stimulated than the nitrite oxidizing bacteria (NOB) at the concentration of 5 µg Cu2+/L. However, approximately equal NH4-N removal rate (ANRR) and NO2-N accumulation rate (NiAR) losses indicated that the AOB and NOB are approximately equally effected at the inlet concentrations of 35 and 50 µg Cu2+/L.

scholarly journals Simultaneous Partial Nitrification and Denitrification Maintained in Membrane Bioreactor for Nitrogen Removal and Hydrogen Autotrophic Denitrification for Further Treatment

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 911
Author(s):  
Kun Dong ◽  
Xinghui Feng ◽  
Wubin Wang ◽  
Yuchao Chen ◽  
Wei Hu ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Dominant Role ◽  
Domestic Sewage ◽  
Biofilm Reactor ◽  
Partial Nitrification ◽  
Ammonia Oxidizing Bacteria ◽  
Autotrophic Denitrification ◽  
Membrane Biofilm Reactor ◽  
N Removal ◽  
Wide Range

Low C/N wastewater results from a wide range of factors that significantly harm the environment. They include insufficient carbon sources, low denitrification efficiency, and NH4+-N concentrations in low C/N wastewater that are too high to be treated. In this research, the membrane biofilm reactor and hydrogen-based membrane biofilm reactor (MBR-MBfR) were optimized and regulated under different operating parameters: the simulated domestic sewage with low C/N was domesticated and the domestic sewage was then denitrified. The results of the MBR-MBfR experiments indicated that a C/N ratio of two was suitable for NH4+-N, NO2−-N, NO3−-N, and chemical oxygen demand (COD) removal in partial nitrification-denitrification (PN-D) and hydrogen autotrophic denitrification for further treatment. The steady state for domestic wastewater was reached when the MBR-MBfR in the experimental conditions of HRT = 15 h, SRT = 20 d, 0.04 Mpa for H2 pressure in MBfR, 0.4–0.8 mg/L DO in MBR, MLSS = 2500 mg/L(MBR) and 2800 mg/L(MBfR), and effluent concentrations of NH4+-N, NO3−-N, and NO2−-N were 4.3 ± 0.5, 1.95 ± 0.04, and 2.05 ± 0.15 mg/L, respectively. High-throughput sequencing results revealed the following: (1) The genus Nitrosomonas as the ammonia oxidizing bacteria (AOB) and Denitratisoma as potential denitrifiers were simultaneously enriched in the MBR; (2) at the genus level, Meiothermus,Lentimicrobium, Thauera,Hydrogenophaga, and Desulfotomaculum played a dominant role in leading to NO3−-N and NO2−-N removal in the MBfR.

scholarly journals Nitrate Removal by Floating Treatment Wetlands Amended with Spent Coffee: A Mesocosm-Scale Evaluation

2019 ◽  
Vol 62 (6) ◽  
pp. 1619-1630
Author(s):  
Mary G. Keilhauer ◽  
Tiffany L. Messer ◽  
Aaron R. Mittelstet ◽  
Thomas G. Franti ◽  
Jessica Corman
Keyword(s):  
Nitrate Removal ◽  
Growing Season ◽  
Treatment Wetlands ◽  
Spent Coffee Grounds ◽  
Nitrate N ◽  
Carbon Amendment ◽  
N Removal ◽  
Coffee Grounds ◽  
Floating Treatment Wetlands ◽  
Wetland Design

HighlightsA floating treatment wetland design was evaluated for water quality improvements.Nitrate-N removal rates were quantified using spent coffee grounds as a carbon source.Nitrate-N removal rates increased throughout the growing season Abstract. The Midwestern U.S. is vulnerable to eutrophic conditions from high nutrient concentrations. Floating treatment wetlands (FTWs) are an innovative wetland design for nutrient removal from nonpoint sources and provide a unique treatment. The objectives of this project were to quantify nitrate removal in traditional and carbon-amended FTWs planted with Midwestern plant species during the establishment year. Three greenhouse experiments were conducted throughout the growing season using 18 mesocosms. Two vegetation designs were evaluated: rush species ( and ) and diverse species (, , , , , and ). Spent coffee grounds were applied to 9 of the 18 mesocosms as a carbon amendment. Nitrate-N removal increased during the establishment growing season in the FTW systems (Spring: 15.0% to 17.3%, Summer 1: 82.8% to 92.6%, Summer 2: 86.4% to 94.7%). Nitrate-N removal was also impacted by carbon amendments (FTW without amendment: 82.8% to 94.7%, FTW with amendment: 88.4% to 96.1%). Carbon additions were found to enhance denitrifying conditions even in the absence of FTWs (decreased dissolved oxygen, increased available organic carbon). Significant differences in nitrate-N removal were not observed between FTW vegetation designs. This study provides new insight on the impacts of the growing season, plant species, and carbon amendments on FTW nitrate-N removal performance during the establishment year. Keywords: Best management practices, Carbon amendment, Floating treatment wetlands, Nitrogen removal, Spent coffee grounds

Total nitrogen removal in an aerobic/anoxic membrane biofilm reactor system

2005 ◽  
Vol 52 (7) ◽  
pp. 115-120 ◽  
Author(s):  
J. Cowman ◽  
C.I. Torres ◽  
B.E. Rittmann
Keyword(s):  
Nitrogen Removal ◽  
Hydrogen Pressure ◽  
Biofilm Reactor ◽  
Total N ◽  
Nitrate N ◽  
Membrane Biofilm Reactor ◽  
N Removal ◽  
Ammonium N ◽  
High O2 ◽  
Total Nitrogen Removal

The hydrogen-based membrane biofilm reactor (MBfR) is effective for reducing nitrate-N to N2 gas, but most wastewaters contain ammonium-N. Here, we document that an aerobic/anoxic MBfR system achieves nearly total N removal (<2 mgN/L) when the influent N is ammonium. The aerobic/anoxic MBfR couples two MBfR modules. The aerobic MBfR is supplied O2 and brings about nitrification of ammonium to nitrate or nitrite. The anoxic MBfR is supplied H2 and brings about denitrification to N2 gas. Total N removal is most strongly influenced by the O2 pressure in the aerobic module: too low O2 caused poor nitrification, while too high O2 inhibited denitrification in the anoxic module. Hydrogen pressure does not strongly affect total-N removal, and the best total-N removal occurs when the H2 and O2 pressures are similar.

scholarly journals Nitrate Removal and Dynamics of Microbial Community of A Hydrogen-Based Membrane Biofilm Reactor at Diverse Nitrate Loadings and Distances from Hydrogen Supply End

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3196
Author(s):  
Minmin Jiang ◽  
Yuanyuan Zhang ◽  
Yuhang Yuan ◽  
Yuchao Chen ◽  
Hua Lin ◽  
...  
Keyword(s):  
Microbial Community ◽  
High Throughput Sequencing ◽  
Nitrate Removal ◽  
Biofilm Reactor ◽  
Back Diffusion ◽  
Membrane Biofilm Reactor ◽  
Functional Bacteria ◽  
Hydrogen Supply ◽  
N Metabolism ◽  
The Impact

The back-diffusion of inactive gases severely inhibits the hydrogen (H2) delivery rate of the close-end operated hydrogen-based membrane biofilm reactor (H2-based MBfR). Nevertheless, less is known about the response of microbial communities in H2-based MBfR to the impact of the gases’ back-diffusion. In this research, the denitrification performance and microbial dynamics were studied in a H2-based MBfR operated at close-end mode with a fixed H2 pressure of 0.04 MPa and fed with nitrate (NO3−) containing influent. Results of single-factor and microsensor measurement experiments indicate that the H2 availability was the decisive factor that limits NO3− removal at the influent NO3− concentration of 30 mg N/L. High-throughput sequencing results revealed that (1) the increase of NO3− loading from 10 to 20–30 mg N/L resulted in the shift of dominant functional bacteria from Dechloromonas to Hydrogenophaga in the biofilm; (2) excessive NO3− loading led to the declined relative abundance of Hydrogenophaga and basic metabolic pathways as well as counts of most denitrifying enzyme genes; and (3) in most cases, the decreased quantity of N metabolism-related functional bacteria and genes with increasing distance from the H2 supply end corroborates that the microbial community structure in H2-based MBfR was significantly impacted by the gases’ back-diffusion.

Nitrate removal by an ultra-compact biofilm reactor

2000 ◽  
Vol 42 (3-4) ◽  
pp. 181-186 ◽  
Author(s):  
S.L. Ong ◽  
W.J. Ng ◽  
L.Y. Lee ◽  
J. Yu ◽  
J. Y. Hu
Keyword(s):  
Conversion Rate ◽  
Nitrate Removal ◽  
Biomass Concentration ◽  
Growth Yield ◽  
Biofilm Reactor ◽  
Yield Coefficient ◽  
Nitrate N ◽  
Density And Biomass ◽  
Stage 1 ◽  
Two Stages

This study consisted of two stages. The first stage was to cultivate denitrifying biofilm with a simplified UCBR while the second stage was to investigate the performance of a standard UCBR for nitrate removal. The volumetric nitrate-N conversion rate increased steadily from less than 0.5 kg/m3.d to about 2.5 kg/m3.d towards the end of Stage 1. Reactor instability and poor biofilm morphology had led to a relatively low nitrate-N conversion rate during stage 1 of operation. In Stage 2, the conversion rate increased rapidly to 6.5 kg/m3.d within 4 days and increased steadily to 10.5 kg/m3.d, thereafter. The biofilm formation in Stage 2 was better than that attained in Stage 1. Biofilm density and biomass concentration in the reactor were in the range of 20.5 to 29.0 g/L and 1 to 3 g/L, respectively. The specific growth rate of the denitrifiers (μ) and the observed biomass growth yield coefficient (Yobs) in the reactor varied within the ranges of 1.5-4.2 d-1 and 0.20-0.65 g biomass/g nitrate-N, respectively. The specific nitrate-N conversion rate (γ) was within the range of 1.8-3.8 g nitrate-N/g biomass.d.

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