Effect of low-intensity electric current field and iron anode on biological nitrate removal in wastewater with low COD to nitrogen ratio from coal pyrolysis

2020 ◽  
Vol 306 ◽  
pp. 123123 ◽  
Author(s):  
Zhengwen Zhang ◽  
Chunyan Xu ◽  
Hongjun Han ◽  
Mengqi Zheng ◽  
Jingxin Shi ◽  
...  
Keyword(s):  
Electric Current ◽  
Nitrate Removal ◽  
Coal Pyrolysis ◽  
Current Field ◽  
Low Intensity ◽  
Nitrogen Ratio ◽  
Iron Anode ◽  
Biological Nitrate Removal

Groundwater denitrification with alternative carbon sources

1998 ◽  
Vol 38 (6) ◽  
pp. 237-243 ◽  
Author(s):  
A. Mohseni-Bandpi ◽  
D. J. Elliott
Keyword(s):  
Acetic Acid ◽  
Carbon Source ◽  
Nitrate Nitrogen ◽  
Nitrogen Concentration ◽  
Nitrate Removal ◽  
Carbon Sources ◽  
Pilot Scale ◽  
Rotating Biological Contactor ◽  
Nitrogen Ratio ◽  
Biological Nitrate Removal

A pilot scale rotating biological contactor (RBC) was used to investigate the removal of nitrate-nitrogen from groundwater using three different carbon sources, i.e., methanol, ethanol and acetic acid. Optimum carbon sources to influent nitrate-nitrogen ratio were established by varying the influent concentration of carbon sources. The optimum ratio of methanol, ethanol and acetic acid to nitrate-nitrogen ratios were found to be 2.9, 2.35 and 4.3 respectively. The nitrate-nitrogen removal efficiency averaged 93, 91 and 98 for methanol, ethanol and acetic acid respectively at a loading rate of 76 mg/m2.h. The results of this study show that the acetic acid is the most efficient carbon source for removal of nitrate-nitrogen. Effluent nitrite-nitrogen concentration was minimum for acetic acid as compared with ethanol and methanol. The effluent contained minimum suspended solids and turbidity for methanol as a carbon source. The results of this study indicate that biological nitrate removal using a RBC is a reliable and stable system under all the three carbon sources. The denitrified water in all cases requires some post treatment to oxidise the residual carbon source and remove biomass before distribution.

scholarly journals The contributions and mechanisms of iron-microbes-biochar in constructed wetlands for nitrate removal from low carbon/nitrogen ratio wastewater

RSC Advances ◽  
2020 ◽  
Vol 10 (39) ◽  
pp. 23212-23220
Author(s):  
Jian Xu ◽  
Xiawei Liu ◽  
Jiaolong Huang ◽  
Manqi Huang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Nitrate Removal ◽  
Schematic Diagram ◽  
Low Carbon ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio

Schematic diagram of RDCWs system and proposed mechanisms for nitrate removal.

Simultaneous oxidation and reduction treatments of polluted water by a bio-electro reactor

1996 ◽  
Vol 34 (9) ◽  
pp. 101-108 ◽  
Author(s):  
M. Kuroda ◽  
T. Watanabe ◽  
Y. Umedu
Keyword(s):  
Aqueous Solution ◽  
Organic Matter ◽  
Electric Current ◽  
Removal Efficiency ◽  
Concentration Ratio ◽  
Nitrate Removal ◽  
Hydrogen Gas ◽  
Polluted Water ◽  
Simultaneous Oxidation ◽  
Denitrifying Microorganisms

Application of a bio-electro reactor for treatment of various kinds of polluted water was investigated experimentally. Aqueous solution of nitrate, ammonium and/or organic matter were used as synthetic polluted water. Denitrification of the nitrate polluted water without organic matter proceeded effectively by utilizing hydrogen gas produced by electrolysis of water in the reactor. The bio-electro reactor was also available for the treatment of nitrate polluted water containing organic matter when the C/N concentration ratio was up to 1.0 under the condition of 100 mA of applied electric current. The nitrate removal efficiency from nitrate polluted water containing acetate at C/N=1.0 was more than 90% at 5 hours of HRT and 80% even at 2.8 h HRT. For the treatment of ammonium polluted water, nitrification and denitrification proceeded simultaneously in a bio-electro reactor where nitrifying and denitrifying microorganisms were immobilized on the electrodes. The results obtained in this study suggested that the bio-electro reactor system was capable to application for oxidation and reduction treatments of the nitrate and ammonium polluted water.

Comparison of denitrification performances using PLA/starch with different mass ratios as carbon source

2015 ◽  
Vol 71 (7) ◽  
pp. 1019-1025 ◽  
Author(s):  
Chuanfu Wu ◽  
Danqi Tang ◽  
Qunhui Wang ◽  
Juan Wang ◽  
Jianguo Liu ◽  
...  
Keyword(s):  
Carbon Source ◽  
Groundwater Remediation ◽  
Nitrate Concentration ◽  
Starch Content ◽  
Nitrate Removal ◽  
Carbon Sources ◽  
National Standard ◽  
Biofilm Carrier ◽  
Carbon Release ◽  
Biological Nitrate Removal

A suitable carbon source is significant for biological nitrate removal from groundwater. In this study, slow-release carbon sources containing polylactic acid (PLA) and starch at 8:2, 7:3, 6:4, 5:5, 4:6, and 3:7 ratios were prepared using a blending and fusing technique. The PLA/starch blend was then used as a solid carbon source for biological nitrate removal. The carbon release rate of PLA/starch was found to increase with increased starch content in leaching experiments. PLA/starch at 5:5 mass ratio was found to have the highest denitrification performance and organic carbon consumption efficiency in semi-continuous denitrification experiments, and was also revealed to support complete denitrification at 50 mg-N/L influent nitrate concentration in continuous experiments. The effluent nitrate concentration was <2 mg NO3–-N/L, which met the national standard (GB 14848-93) for groundwater. Scanning electron microscopy results further showed that the surface roughness of PLA/starch increased with prolonged experimental time, which may be conducive to microorganism attachment. Therefore, PLA/starch was a suitable carbon source and biofilm carrier for groundwater remediation.

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