Nitrate Removal with Sulfur-Limestone Autotrophic Denitrification Processes

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.

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Sulfur-Based Autotrophic Denitrification for Nitrate Removal in Marine Recirculating Aquaculture Systems

Proceedings of the Water Environment Federation ◽

10.2175/193864718824940709 ◽

2018 ◽

Vol 2018 (5) ◽

pp. 321-331

Author(s):

Qiaochong He ◽

Zhang Cheng ◽

Victoria Burnett ◽

Sarina J Ergas

Keyword(s):

Nitrate Removal ◽

Autotrophic Denitrification ◽

Recirculating Aquaculture ◽

Recirculating Aquaculture Systems

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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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