Effect of nitrate concentration, pH, and hydraulic retention time on autotrophic denitrification efficiency with Fe(II) and Mn(II) as electron donors

The role of electron donors (Fe2+ and Mn2+) in the autotrophic denitrification of contaminated groundwater by bacterial strain SY6 was characterized based on empirical laboratory-scale analysis. Strain SY6 can utilize Fe2+ more efficiently than Mn2+ as an electron donor. This study has shown that the highest nitrate removal ratio, observed with Fe2+ as the electron donor, was approximately 88.89%. An immobilized biological filter reactor was tested by using three levels of influent nitrate (10, 30, and 50 mg/L), three pH levels (6, 7, and 8), and three levels of hydraulic retention time (HRT; 6, 8, and 12 h), respectively. An optimal nitrate removal ratio of about 95% was achieved at pH 6.0 using a nitrate concentration of 50 mg/L and HRT of 12 h with Fe2+ as an electron donor. The study showed that 90% of Fe2+ and 75.52% removal of Mn2+ were achieved at pH 8.0 with a nitrate concentration of 50 mg/L and a HRT of 12 h. Removal ratio of Fe2+ and Mn2+ is higher with higher influent nitrate and HRT. A weakly alkaline environment assisted the removal of Fe2+ and Mn2+.

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

Water Science & Technology Water Supply ◽

10.2166/ws.2017.049 ◽

2017 ◽

Vol 17 (6) ◽

pp. 1673-1681 ◽

Cited By ~ 1

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.

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Autotrophic denitrification of landfill leachate using elemental sulphur

Water Science & Technology ◽

10.2166/wst.1996.0584 ◽

1996 ◽

Vol 34 (5-6) ◽

pp. 469-476 ◽

Cited By ~ 49

Author(s):

A. Koenig ◽

L. H. Liu

Keyword(s):

Particle Size ◽

Retention Time ◽

Hydraulic Retention Time ◽

Loading Rate ◽

Nitrate Removal ◽

Packed Bed ◽

Elemental Sulphur ◽

Limiting Factor ◽

Autotrophic Denitrification ◽

Sulphur Particle

One of the most economical means of nitrogen removal from leachate is biological treatment by nitrification, followed by heterotrophic denitrification. An alternative biological denitrification process is autotrophic denitrification using Thiobacillus denitrificans. This autotrophic bacteria oxidizes elemental sulphur to sulphate while reducing nitrate to elemental nitrogen gas, thereby eliminating the need for addition of organic carbon compounds. For this study, pilot-scale elemental sulphur packed bed columns with fixed-film denitrification have been selected as the most suitable treatment process. The effect of hydraulic retention time as well as the effect of concentration and loading rate of nitrate on nitrate removal efficiency as a function of sulphur particle size were determined. The results indicate that (i) autotrophic denitrification can effectively remove nitrate from synthetic and actual nitrified leachate at concentrations much higher than hitherto reported; (ii) the minimum hydraulic retention time necessary for complete denitrification depends on sulphur particle size; (iii) the maximum area loading rate, in g NO3−-N/m2·d, appears to be the process limiting factor and is practically independent of sulphur particle size; and (iv) the observed stoichiometric relationships compare well with those previously reported.

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Simultaneous removal of Fe3+ and nitrate in the autotrophic denitrification immobilized systems

Water Science & Technology Water Supply ◽

10.2166/ws.2017.186 ◽

2017 ◽

Vol 18 (5) ◽

pp. 1625-1634

Author(s):

Jun feng Su ◽

Ting ting Lian ◽

Ting lin Huang ◽

Dong hui Liang ◽

Wen dong Wang

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Retention Time ◽

Hydraulic Retention Time ◽

Removal Rate ◽

Nitrate Removal ◽

Simultaneous Removal ◽

Autotrophic Denitrification ◽

Four Levels ◽

Experimental Group

Abstract In this study, strain CC76, identified as Enterobacter sp., was tested for the reduction of Fe3+ and denitrification using immobilized pellets with strain CC76 as experimental group (IP) and immobilized pellets with strain CC76 and magnetite powder as experimental group (IPM) in the autotrophic denitrification immobilized systems (ADIS). Compared with IP, a higher nitrate removal rate was obtained with IPM by using three levels of influent Fe3+ (0, 5, and 10 mg/L), four levels of pH (5.0, 6.0, 7.0, and 8.0), and three levels of hydraulic retention time (HRT) (12, 14, and 16 h), respectively. Furthermore, response surface methodology (RSM) analysis demonstrated that the optimum removal ratios of nitrate of 87.21% (IP) and 96.27% (IPM) were observed under the following conditions: HRT of 12 h, pH of 7.0 and influent Fe3+ concentration of 5 mg/L (IP) and 1 mg/L (IPM).

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Effects of hydraulic retention time and ratio on thiosulfate-driven autotrophic denitrification for nitrate removal from micro-polluted surface water

Environmental Technology ◽

10.1080/09593330.2017.1278794 ◽

2017 ◽

Vol 38 (22) ◽

pp. 2835-2843 ◽

Cited By ~ 2

Author(s):

Zheng Wang ◽

Xiang Fei ◽

Sheng-bing He ◽

Jung-chen Huang ◽

Wei-li Zhou

Keyword(s):

Surface Water ◽

Retention Time ◽

Hydraulic Retention Time ◽

Nitrate Removal ◽

Autotrophic Denitrification

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Role of hydraulic retention time and granular medium in microbial removal in tertiary treatment reed beds

Water Research ◽

10.1016/s0043-1354(03)00066-6 ◽

2003 ◽

Vol 37 (11) ◽

pp. 2645-2653 ◽

Cited By ~ 43

Author(s):

Joan Garcı́a ◽

Joan Vivar ◽

Maria Aromir ◽

Rafael Mujeriego

Keyword(s):

Retention Time ◽

Granular Medium ◽

Hydraulic Retention Time ◽

Tertiary Treatment ◽

Reed Beds ◽

Microbial Removal

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Removal of Total Coliform and TSS for Hospital Wastewater by Optimizing the Role of Typha Angustifolia and Fine Sand-Gravel Media in Horizontal Sub Surface Flow Constructed Wetland

Jurnal Riset Teknologi Pencegahan Pencemaran Industri ◽

10.21771/jrtppi.2021.v12.no1.p20-31 ◽

2021 ◽

Vol 12 (1) ◽

pp. 20-31

Author(s):

Abdul Gani Akhmad

Keyword(s):

Retention Time ◽

Hydraulic Retention Time ◽

Fine Sand ◽

Pilot Scale ◽

Total Coliform ◽

Surface Flow ◽

Pollutant Removal ◽

Typha Angustifolia ◽

Hospital Wastewater

This study aims to evaluate the performance of a pilot-scale HSSF-CW utilizing Typha angustifolia and fine sand-gravel media in removing total coliform and TSS from hospital wastewater. Three pilot-scale HSSF-CW cells measuring 1.00 x 0.45 x 0.35 m3 were filled with gravel sand media with a diameter of 5 - 8 mm as high as 35 cm with a submerged media depth of 0.30 m. There were three treatments, namely the first cell (CW1) without plants, the second cell (CW2) was planted with a density of 12 Typha angustifolia plants, and the third cell (CW3) was planted with a density of 24 Typha angustifolia plants. The three HSSF-CW cells received the same wastewater load with total coliform and TSS contents of 91000 MPN / 100 mg and 53 mg / L, respectively, with Hydraulic Loading Rates 3,375 m3 per day. Wastewater was recirculated continuously to achieve the equivalent HSSF-CW area requirement. The experimental results show that the performance of CW3 is more efficient than CW1 and CW2 in total coliform and TSS removal for hospital wastewater. The pollutant removal efficiency at CW3 reached 91.76% for total coliform with one day hydraulic retention time and 81.00% for TSS with two days of hydraulic retention time. This study concludes that the HSSF-CW system using sand-gravel media with a diameter of 5 - 8 mm with a submerged media depth of 0.30 m and planted with Typha angustifolia with a tighter spacing proved to be more efficient in removing total coliform and TSS from hospital wastewater.

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Anoxic Microbial Community Robustness Under Variation of Hydraulic Retention Time and Availability of Endogenous Electron Donors

Applied Biochemistry and Biotechnology ◽

10.1007/s12010-020-03327-5 ◽

2020 ◽

Vol 192 (2) ◽

pp. 443-454

Author(s):

Dagoberto Y. Okada ◽

Rachel B. Costa ◽

Caroline de Cassia B. Garcia ◽

Eloisa Pozzi ◽

Theo S. O. Souza ◽

...

Keyword(s):

Microbial Community ◽

Retention Time ◽

Hydraulic Retention Time ◽

Electron Donors

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Enhancement of nitrate removal in synthetic groundwater using wheat rice stone

Water Science & Technology ◽

10.2166/wst.2012.279 ◽

2012 ◽

Vol 66 (9) ◽

pp. 1900-1907 ◽

Cited By ~ 7

Author(s):

Siqi Hong ◽

Jianmei Zhang ◽

Chuanping Feng ◽

Baogang Zhang ◽

Puxi Ma

Keyword(s):

Trace Elements ◽

Activated Carbon ◽

Retention Time ◽

Hydraulic Retention Time ◽

Nitrate Removal ◽

Oxygen Demand ◽

Nitrite Accumulation ◽

Synthetic Groundwater ◽

Biofilm Carriers ◽

Growth Of Bacteria

To enhance the efficiency of nitrate removal from synthetic groundwater, wheat rice stone (WRS) and granular activated carbon (GAC) were employed as biofilm carriers for denitrification under different HRT (hydraulic retention time) and C/N ratios. Four different ratios of GAC to WRS (0, 0.5, 1.0, and 2.0) were investigated to determine the most appropriate ratio of GAC and WRS. The NO3−-N, NO2−-N, COD levels and pH of the effluent were also investigated under various HRT and C/N ratios. The results showed that the column at a GAC/WRS ratio of 1.0 performed best under a C/N ratio of 0.9 and an HRT of 8 h, with 99% nitrate being removed. In addition, little nitrite accumulation and chemical oxygen demand (COD) were observed in effluent under these conditions. These results demonstrated that, with no addition of phosphor in the influent, the nitrate removal efficiency can be enhanced by WRS because WRS can leach trace elements and phosphor to promote the growth of bacteria.

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