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

2017 ◽  
Vol 38 (22) ◽  
pp. 2835-2843 ◽  
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

Autotrophic denitrification of landfill leachate using elemental sulphur

1996 ◽  
Vol 34 (5-6) ◽  
pp. 469-476 ◽  
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.

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

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).

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

2016 ◽  
Vol 74 (5) ◽  
pp. 1185-1192 ◽  
Author(s):  
Jun-feng Su ◽  
Jing-xin Shi ◽  
Ting-lin Huang ◽  
Fang Ma ◽  
Jin-suo Lu ◽  
...  
Keyword(s):  
Electron Donor ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Nitrate Concentration ◽  
Nitrate Removal ◽  
Electron Donors ◽  
Autotrophic Denitrification ◽  
Weakly Alkaline ◽  
Removal Ratio

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+.

Enhancement of nitrate removal in synthetic groundwater using wheat rice stone

2012 ◽  
Vol 66 (9) ◽  
pp. 1900-1907 ◽  
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.

Effect of sawdust dosage and hydraulic retention time (HRT) on nitrate removal in sawdust/pyrite mixotrophic denitrification (SPMD) systems

2019 ◽  
Vol 5 (2) ◽  
pp. 346-357 ◽  
Author(s):  
Shunlong Jin ◽  
Chuanping Feng ◽  
Shuang Tong ◽  
Nan Chen ◽  
Hengyuan Liu ◽  
...  
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Nitrate Removal ◽  
Contaminated Aquifer ◽  
Aquifer Remediation

Pyrite plays an important role in nitrate-contaminated aquifer remediation.

Comparison of heterotrophic and autotrophic denitrification processes for nitrate removal from phosphorus-limited surface water

2018 ◽  
Vol 238 ◽  
pp. 562-572 ◽  
Author(s):  
Zheng Wang ◽  
Shengbing He ◽  
Jungchen Huang ◽  
Weili Zhou ◽  
Wanning Chen
Keyword(s):  
Surface Water ◽  
Nitrate Removal ◽  
Autotrophic Denitrification ◽  
Limited Surface

Application of light-weight filtration media in an anoxic biofilter for nitrate removal from micro-polluted surface water

2016 ◽  
Vol 74 (4) ◽  
pp. 1016-1024 ◽  
Author(s):  
Zheng Wang ◽  
Xiang Fei ◽  
Shengbing He ◽  
Jungchen Huang ◽  
Weili Zhou
Keyword(s):  
Surface Water ◽  
Removal Efficiency ◽  
Sodium Acetate ◽  
Consumption Rate ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Nitrate Nitrogen ◽  
Nitrate Removal ◽  
Light Weight ◽  
Stage Process

The research investigated nitrate removal from micro-polluted surface water by the single-stage process of anoxic biofilter using light-weight polystyrene beads as filtration media. In this study, sodium acetate was used as an external carbon source and the nitrate removal efficiency under different regimes of hydraulic loading rate (HLR), water temperature, and C/N ratio was studied. In addition, the effect of backwash on denitrification efficiency was investigated. The results show that the biofilter achieved a high nitrate removal efficiency in 2 weeks at water temperatures ranging between 22 and 25 °C at a C/N ratio (COD:NO3−-N) of 6:1. Besides, the average removal efficiency of nitrate at HLRs of 5.66, 7.07 and 8.49 m3 m−2 h−1 were 87.5, 87.3 and 87.1%, respectively. The average removal efficiency of nitrate nitrogen was 13.9% at a HLR of 5.66 m3 m−2 h−1 at water temperatures of 12–14 °C, then it increased to 93.7% when the C/N ratio increased to 10. It suggests that the optimal hydraulic retention time is at water temperatures of 8–10 °C. The water consumption rate of backwash was about 0.2–0.3%, and denitrification efficiency returned to the normal level in 12 h after backwash.

scholarly journals Effect of saline drainage water on performance of denitrification bioreactors

2020 ◽  
Author(s):  
Sasan Faramarzmanesh ◽  
Mahmoud Mashal ◽  
Seyyed Ebrahim Hashemi Garmdareh
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Nitrate Removal ◽  
Drainage Water ◽  
The Other ◽  
Salinity Level ◽  
Main Element ◽  
Biological Denitrification ◽  
Removal Process ◽  
Positive Effect

Abstract Excessive use of nitrate fertilizers in agriculture causes harm to humans and the environment. The most suitable nitrate removal process is heterotrophic biological denitrification. The purpose of the present study was to evaluate the performance of three shapes of denitrification bioreactors: triangular, rectangular and semicircular. The main element that was used to remove nitrate was beech woodchips. The concentration of inlet nitrate was 75 mg/l and the salinity of the solution was 1 ds/m and 5 ds/m, for a period of six months. The results showed that the efficiency of the triangular bioreactor with a salinity level of 1 ds/m was 90%, which is more efficient than the rectangular and semicircular bioreactors with performances of 55.8% and 53.8%, respectively. The results also indicated that at a salinity level of 5 ds/m, the semicircular bioreactor with a performance of 50.8% inlet nitrate removal was the best of the three shapes of bioreactors tested, the efficiencies of the triangular and rectangular bioreactors were 49.9% and 48.6% respectively. Also, it was observed that at the salinity level of 1 ds/m, a high hydraulic retention time had a high positive effect on denitrification, on the other hand at the salinity level of 5 ds/m, there was better performance of denitrification if the hydraulic retention time was lower.

Nitrogen Removal Optimization in a Biofilm Reactor from Groundwater

2012 ◽  
Vol 518-523 ◽  
pp. 2604-2607
Author(s):  
Chang Hang Wu ◽  
Yun Xiao Jin
Keyword(s):  
Nitrogen Removal ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Nitrate Removal ◽  
Biofilm Reactor

In the present study a lab-scale biofilm reactor was monitored for approximately 6 months to evaluate the use of ratios of carbon to nitrogen (C/N), pH and hydraulic retention time(HRT) levels as monitoring parameters in order to optimize nitrate removal from groundwater. The results indicated it was possible to operate the biofilm system at high denitrification rates and relatively low HRT of 8 hours.

Woodchip Denitrification Bioreactors: Impact of Temperature and Hydraulic Retention Time on Nitrate Removal

2016 ◽  
Vol 45 (3) ◽  
pp. 803-812 ◽  
Author(s):  
Natasha L. Hoover ◽  
Alok Bhandari ◽  
Michelle L. Soupir ◽  
Thomas B. Moorman
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Nitrate Removal
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