Effective denitrification process by a low voltage in a multi-cathode bio-electrode film reactor

RSC Advances ◽  
2015 ◽  
Vol 5 (17) ◽  
pp. 13061-13067 ◽  
Author(s):  
Ruqiong Cao ◽  
Diwen Ying ◽  
Chenjun Li ◽  
Yalin Wang ◽  
Jinping Jia
Keyword(s):  
Low Voltage ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Film Reactor ◽  
Denitrification Process

An outstanding nitrate removal rate of 16.8 NO3−–N mg L−1 h−1 was achieved by applying voltage of 0.25 V in a multi-cathode bio-electrode film reactor.

scholarly journals Biological Removal of Nitrates from Groundwater Resources in Saudi Arabia

2020 ◽  
Vol 14 (3) ◽  
pp. 2203-2213
Author(s):  
Essam J. Alyamani ◽  
Rayan Y. Booq ◽  
Ali H. Bahkali ◽  
Sulaiman A. Alharbi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Saudi Arabia ◽  
Removal Rate ◽  
Groundwater Resources ◽  
Nitrate Removal ◽  
Reduction Rate ◽  
Denitrifying Bacteria ◽  
Molecular Techniques ◽  
Microbial Cellulose ◽  
Denitrification Process

Groundwater is the main water source for many areas in Saudi Arabia and the only source of water in some areas. Many local studies have reported that high nitrate concentrations in some wells of groundwater. To provide safe drinking water, the excess amounts of nitrate have to be removed by bio-denitrification process. This study aims to develop a denitrifying biological filter using denitrifying bacteria immobilized on microbial cellulose for the removal of nitrates from water contaminated with nitrate. Denitrifying bacteria that can form biofilter on microbial cellulose were isolated from different regions in Saudi Arabia and were characterized by molecular techniques. They were evaluated for their ability to analyze nitrates and to develop biofilter to remove nitrates from contaminated water. In the results of this project, an optimal microbial cellulose production was achieved by Gluconacetobacter xylinus ATCC 23768 in the lab, which had facilitated the use of biofilter with the immobilized nitrate-reducing bacteria Pseudomonas aeruginosa. The reduction rate of nitrate was reached 1.9mg/L from the starting concentration of 100 mg/L after 18h. Promising results of nitrate removal rate on MC immobilized with Pseudomonas aeruginosa on biofilter at optimized lab conditions of pH, and proper carbon source were achieved. The results suggest that water contaminated with nitrate can be removed by the bio-denitrification process effectively.

Optimal operations for groundwater denitrification of drinking water using heterotrophic biological denitrification process

2006 ◽  
Vol 6 (2) ◽  
pp. 125-130
Author(s):  
C.-H. Hung ◽  
K.-H. Tsai ◽  
Y.-K. Su ◽  
C.-M. Liang ◽  
M.-H. Su ◽  
...  
Keyword(s):  
Drinking Water ◽  
Removal Efficiency ◽  
Nitrate Removal ◽  
Drinking Water Treatment ◽  
Nitrate Content ◽  
Source Water ◽  
Nitrogen Gas ◽  
Negative Effect ◽  
Denitrification Process ◽  
Heterotrophic Denitrification

Due to the extensive application of artificial nitrogen-based fertilizers on land, groundwater from the central part of Taiwan faces problems of increasing concentrations of nitrate, which were measured to be well above 30 mg/L all year round. For meeting the 10 mg/L nitrate standard, optimal operations for a heterotrophic denitrification pilot plant designed for drinking water treatment was investigated. Ethanol and phosphate were added for bacteria growing on anthracite to convert nitrate to nitrogen gas. Results showed that presence of high dissolved oxygen (around 4 mg/L) in the source water did not have a significantly negative effect on nitrogen removal. When operated under a C/N ratio of 1.88, which was recommended in the literature, nitrate removal efficiency was measured to be around 70%, sometimes up to 90%. However, the reactor often underwent severe clogging problems. When operated under C/N ratio of 1.0, denitrification efficiency decreased significantly to 30%. Finally, when operated under C/N ratio of 1.5, the nitrate content of the influent was almost completely reduced at the first one-third part of the bioreactor with an overall removal efficiency of 89–91%. Another advantage for operating with a C/N ratio of 1.5 is that only one-third of the biosolids was produced compared to a C/N value of 1.88.

scholarly journals Impact of Temperature on Biological Denitrification Process

1970 ◽  
Vol 7 (1) ◽  
pp. 121-126 ◽  
Author(s):  
Iswar Man Amatya ◽  
Bhagwan Ratna Kansakar ◽  
Vinod Tare ◽  
Liv Fiksdal
Keyword(s):  
Filtration Rate ◽  
Nitrate Nitrogen ◽  
Nitrate Removal ◽  
Biological Method ◽  
Biological Denitrification ◽  
Nitrite Nitrogen ◽  
Nitrogen Concentrations ◽  
In Series ◽  
Nitrate And Nitrite ◽  
Denitrification Process

Nitrate removal in groundwater was carried out by biological method of denitrification process. The denitrification and without denitrification were performed in two different sets of reactors. Each reactor consists of two columns connected in series packed with over burnt bricks as media. The filtration rate varied from 5.3 to 52.6 m/day for denitrification process. The ammonia, nitrate and nitrite nitrogen concentrations were measured at inlet, intermediate ports and outlet. The temperature varied from 10 to 30°C at 2°C intervals. The results demonstrated that high amount of nitrate nitrogen removed in groundwater at denitrification process. The nitrate nitrogen removed by denitrification varied from 3.50 to 39.08 gm/m3/h at influent concentration from 6.32 to 111.04 gm/m3/h. Denitrification was found more significant above 16°C.Key words: Over burnt brick, Denitrification, Filtration rate and TemperatureJournal of the Institute of Engineering, Vol. 7, No. 1, July, 2009 pp. 121-126doi: 10.3126/jie.v7i1.2070 

Polyacrylamide Wastewater Treatment in a Nested Biofilm Airlift Suspension Reactor

2013 ◽  
Vol 864-867 ◽  
pp. 1608-1611
Author(s):  
Zhong Chen Yu ◽  
Dong Ma ◽  
Song Wang ◽  
Xue Jiao Zhang
Keyword(s):  
Wastewater Treatment ◽  
Oil Recovery ◽  
Large Scale ◽  
Produced Water ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Ammonia Nitrogen ◽  
Walnut Shell ◽  
Biofilm Thickness ◽  
Tertiary Oil Recovery

Polyacrylamide has been widely used in tertiary oil recovery. Oilfield produced water in a large scale contain polyacrylamide, leading to oilfield environment pollution. In this paper, the nested loops biofilm airlift suspension reactor was used in polyacrylamide wastewater treatment. In the reactor, wastewater can alternately flow through the hypoxic environment fixed light carriers and aerobic environment suspended walnut shell biological carriers, achieving simultaneous removal of organic matter and nitrogen. The influencing factors on the organic compound degradation and denitrification performance were studied. Biological and hydrodynamic model of nitrogen and carbon removal was established. Also, the biological phase structure of the carrier biofilm was observed. The results show that polyacrylamide degradation and ammonia nitrogen removal rate are around 30% and 95%, respectively when the experimental hydraulic retention time is 24h. Due to poor denitrification efficiency; nitrate removal rate is only 20%. The carrier biofilm thickness is appropriate, and filamentous bacteria occupy the dominant position.

scholarly journals Nitrate Removal from Groundwater by Denitrification in Fixed and Fluidized Bed Biofilm Reactors A Comparative Study

2019 ◽  
Vol 70 (1) ◽  
pp. 297-300
Author(s):  
Ion Viorel Patroescu ◽  
Ioana Alexandra Ionescu ◽  
Lucian Alexandru Constantin ◽  
Laurentiu Razvan Dinu ◽  
Valeriu Robert Badescu
Keyword(s):  
Fluidized Bed ◽  
Nitrate Removal ◽  
Fixed Bed ◽  
Size Fraction ◽  
Particle Size Fraction ◽  
Fluidized Bed Bioreactor ◽  
Biofilm Reactors ◽  
Attached Biomass ◽  
Denitrification Process ◽  
Bioreactor Types

The influence of attached biomass bioreactor types on the denitrification process using a low-pitched groundwater containing nitrates was studied. Two types of fixed-bed and fluidized-bed biofilm reactors, equipped with expanded clay granular filler, with a particle size fraction of 2-5 mm were used. The nitrite and nitrate concentrations in the inflow and outflow of the two bioreactors were analytically determined. Based on the obtained concentration values, the denitrification rates were calculated, ranging between 1275�1387 g NO3-N/m3/day in the case of the fixed bioreactor and between 3390�3867 g NO3-N/m3/day in the case of the fluidized bed bioreactor.

scholarly journals Nitrate Removal from Actual Wastewater by Coupling Sulfur-Based Autotrophic and Heterotrophic Denitrification under Different Influent Concentrations

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2913
Author(s):  
Feng Liu ◽  
Suqin Wang ◽  
Xuezhi Zhang ◽  
Feiyue Qian ◽  
Yaobing Wang ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Nitrate Removal ◽  
Operating Conditions ◽  
Coupled Systems ◽  
Polluted Water ◽  
Sequencing Analysis ◽  
Autotrophic Denitrification ◽  
Actual Wastewater ◽  
Denitrification Process ◽  
Heterotrophic Denitrification

Contamination of wastewater with organic-limited nitrates has become an urgent problem in wastewater treatment. The cooperating heterotrophic with sulfur autotrophic denitrification is an alternative process and the efficiency has been assessed in many studies treating simulated wastewater under different operating conditions. However, due to the complex and diverse nature of actual wastewater, more studies treating actual wastewater are still needed to evaluate the feasibility of collaborative denitrification. In this study, lab-scale experiments were performed with actual nitrate polluted water of two different concentrations, with glucose and sodium thiosulfate introduced as mixed electron donors in the coupling sulfur-based autotrophic and heterotrophic denitrification. Results showed that the optimum denitrification performance was exhibited when the influent substrate mass ratio of C/N/S was 1.3/1/1.9, with a maximum denitrification rate of 3.52 kg NO3−-N/(m3 day) and nitrate removal efficiency of 93% in the coupled systems. Illumina high-throughput sequencing analysis revealed that autotrophic, facultative, and heterotrophic bacteria jointly contributed to high nitrogen removal efficiency. The autotrophic denitrification maintained as the predominant process, while the second most prevalent denitrification process gradually changed from heterotrophic to facultative with the increase of influent concentration at optimum C/N/S ratio conditions. Furthermore, the initiation of dissimilatory nitrate reduction to ammonium (DNRA) was very pivotal in promoting the entire denitrification process. These results suggested that sulfur-based autotrophic coupled with heterotrophic denitrifying process is an alternative and promising method to treat nitrate containing wastewater.

scholarly journals Design and operation of submerged layer in bioretention for enhanced nitrate removal

2019 ◽  
Vol 68 (8) ◽  
pp. 744-756 ◽  
Author(s):  
Junyu Zhang ◽  
Rajendra Prasad Singh ◽  
Yunzhe Liu ◽  
Dafang Fu
Keyword(s):  
Activated Carbon ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Yangtze River Delta ◽  
Lake Basin ◽  
Modified Activated Carbon ◽  
N Removal ◽  
Tai Lake ◽  
N 93 ◽  
Tai Lake Basin

Abstract Bioretention, initially designed for treating discontinuous runoff pollution, faces considerable challenges in its trade-off between the hydraulic retention time (HRT) and its treatment capacity. In this study, six enhanced submerged media together with four HRTs were designed for bioretention cells to treat the highly nitrogenous river water in Tai lake basin in Yangtze River delta, China. Results revealed that bioretention with activated carbon has the highest removal of nitrate (NO3−-N) (93–96%) compared with surfactant-modified activated carbon (SMAC), surfactant-modified zeolite (SMZ), zeolite, fly ash and ceramsite. Although the SMAC had the best absorption for NO3−-N and could desorb NO3−-N when its concentration was low in the submerged layer, the desorbed surfactant could inhibit the growth of denitrifying bacteria, which leads to low removal efficiency (49–66%). The dynamic balancing of NO3−-N desorption and denitrifying system restrain in the SMAC device was observed and explained. The best activated carbon-gravel proportion in the submerged layer was 1:1 (150 mm). Such design could ensure the stable and efficient NO3−-N removal rate (93–94%) under high inflow concentration (28.9 mg/L) and high hydraulic loading (8.2 cm/h).

Nitrate removal rate in a continuous column denitrification reactor using hydrogen generated by electrolysis with carbon anodes and stainless cathodes

2002 ◽  
Vol 46 (11-12) ◽  
pp. 39-44 ◽  
Author(s):  
S. Dadang ◽  
T. Kawanishi ◽  
N. Shimizu ◽  
Y. Hayashi
Keyword(s):  
Activated Carbon ◽  
Removal Rate ◽  
Tap Water ◽  
Nitrate Removal ◽  
Fixed Bed ◽  
Reduction Rate ◽  
Potassium Nitrate ◽  
Nitrite Reduction ◽  
Flow Process ◽  
Carbon Anodes

An autotrophic continuous denitrification process, using hydrogen generated by electrolysis with activated carbon anodes, was experimentally demonstrated to be an effective nitrate removal process. Several fixed bed columns with polypropylene packing and honeycomb shaped activated carbon anodes and stainless rod cathodes were set in a thermostat chamber at 30°C, and potassium nitrate enriched tap water as influent was supplied at various flow rates and electric currents. Although the anode is in the same column where microbial biomass grows, sufficient nitrate removal was observed. For example, almost complete removal of nitrate and nitrite was observed at a hydraulic retention time (HRT) as short as 1.8 h. A model assuming successive denitrification reactions and plug-flow process, nitrate reduction rate = k1[NO3−] [H2], and nitrite reduction rate = k2 [NO2−]H2]1.5 was proposed. Calculated results with k1 = 1.3 mmol−1 h−1 and k2 = 3.3 mmol−1.5•h−1 agreed well with all the experimental results.

Oxygen reduces denitrification in biofilm reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 83-91 ◽  
Author(s):  
C. Hagedorn-Olsen ◽  
I. H. Møller ◽  
H. Tøttrup ◽  
P. Harremoës
Keyword(s):  
Organic Matter ◽  
Oxygen Concentration ◽  
Nitrate Removal ◽  
Full Scale ◽  
Laboratory Scale ◽  
Oxygen Penetration ◽  
Biofilm Reactors ◽  
Fixed Film ◽  
Half Power ◽  
Denitrification Process

The mechanism for the nitrate removal from wastewater in a submerged fixed film filter is reviewed and evaluated to demonstrate that the denitrification process is significantly reduced by the presence of oxygen. The kinetics were developed for a fully nitrate penetrated biofilm, influenced by oxygen. It was demonstrated that there is a linear reduction of the denitrification rate with depth of oxygen penetration, proportional to the oxygen concentration to the half power. For a partly nitrate penetrated biofilm the influence of oxygen is a function of the ratio between the penetration of oxygen and the penetration of nitrate without the influence of oxygen. The phenomenon was investigated in laboratory scale with biocarbone and biostyr as media and at a full scale biocarbone plant. The investigation was performed with organic matter in excess on a thin biofilm taken directly from a full scale plant. The results of the experiments with influence of oxygen fit the kinetic concepts well.

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