Use of limestone for pH control in autotrophic denitrification: continuous flow experiments in pilot-scale packed bed reactors

Alkalinity requirement and the possibility of simultaneous heterotrophic denitrification during sulfur-utilizing autotrophic denitrification were evaluated with sulfur packed bed reactors (SPBRs). SPBR showed >99% NO3--N removal efficiency at influent NO3--N concentration of 1,500 mg/L, although 25-40% of the added NO3--N was recovered as N2O. Complete denitrification without N2O production was achieved when the influent NO3--N concentration decreased to 750 mg/L. When nitrified landfill leachate containing 602–687 mg/L of NO3--N was fed to SPBR, denitrification efficiency was greater than 98%. During leachate treatment, alkalinity consumption was 3.25–3.76 g CaCO3/g NO3--N removed. Most of denitrification activity occurred within bottom 11.5 cm of sulfur layer, meaning that effective HRT of 2.34 hours was enough for the complete denitrification at the loading rate of 2.2 kg NO3--N/m3-day. Complete denitrification was also achieved when methanol was added to nitrified leachate without alkalinity addition. In this case, alkalinity produced by heterotrophs was used for sulfur-utilizing denitrification.

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Evaluation of Fe(II)-driven autotrophic denitrification in packed-bed reactors at different nitrate loading rates

Process Safety and Environmental Protection ◽

10.1016/j.psep.2020.05.049 ◽

2020 ◽

Vol 142 ◽

pp. 317-324 ◽

Cited By ~ 2

Author(s):

Kyriaki Kiskira ◽

Stefano Papirio ◽

Yoan Pechaud ◽

Silvio Matassa ◽

Eric D. van Hullebusch ◽

...

Keyword(s):

Packed Bed ◽

Autotrophic Denitrification ◽

Packed Bed Reactors ◽

Loading Rates

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Nitrate and phosphate removal in sulphur-coral stone autotrophic denitrification packed-bed reactors

Journal of Environmental Engineering and Science ◽

10.1680/jees.2013.0028 ◽

2013 ◽

Vol 8 (2) ◽

pp. 267-276

Author(s):

Yun-Jie Ruan ◽

Guo-Zhi Luo ◽

Hong-Xin Tan ◽

Xuan Che ◽

Yan Jiang ◽

...

Keyword(s):

Packed Bed ◽

Phosphate Removal ◽

Autotrophic Denitrification ◽

Packed Bed Reactors

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Nitrate and phosphate removal in sulphur-coral stone autotrophic denitrification packed-bed reactorsA paper submitted to the Journal of Environmental Engineering and Science.

Canadian Journal of Civil Engineering ◽

10.1139/l09-030 ◽

2009 ◽

Vol 36 (5) ◽

pp. 923-932 ◽

Cited By ~ 4

Author(s):

Yun-Jie Ruan ◽

Guo-Zhi Luo ◽

Hong-Xin Tan ◽

Xuan Che ◽

Yan Jiang ◽

...

Keyword(s):

Water Temperature ◽

Removal Efficiency ◽

Loading Rate ◽

Removal Rate ◽

Packed Bed ◽

Pilot Scale ◽

Phosphate Removal ◽

Environmental Engineering ◽

Nitrite Accumulation ◽

Autotrophic Denitrification

The removal effect on nitrate and phosphate of a sulphur-based autotrophic denitrifying bioreactor in composite packing of sulphur with coral stone were investigated on a pilot scale. The results showed that the optimal influent loading rate of the bioreactor (the ratio of sulphur volume to coral stone volume was 1:1) was in the range of 0.080–0.244 kg NO3–-N/(m3·d) when the water temperature was 29 ± 1 °C. In this range, the removal efficiency of nitrates was higher than 95% and no nitrite accumulation occurred in the effluent. The maximum nitrate volumetric removal rate of 0.594 kg NO3–-N / (m3·d) was achieved at an influent loading rate of 0.716 kg NO3–-N/(m3·d) with obvious nitrite accumulation in the effluent. Along with the autotrophic denitrifying reaction, an influent loading rate between 0.070–0.210 kg PO43–-P/ (m3·d) achieved the removal efficiency and volumetric removal rate of phosphates were 50.5%–89.2% and 0.045–0.179 kg PO43–-P/(m3·d), respectively. The phosphates related to the resistance ability of the bioreactor (the ratio of sulphur volume to coral stone volume was 1:1) was stronger than that of bioreactors (the ratio of sulphur volume to coral stone volume was 1:2 and 1:4).

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Continuous-flow enantioselective α-aminoxylation of aldehydes catalyzed by a polystyrene-immobilized hydroxyproline

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.7.172 ◽

2011 ◽

Vol 7 ◽

pp. 1486-1493 ◽

Cited By ~ 45

Author(s):

Xacobe C Cambeiro ◽

Rafael Martín-Rapún ◽

Pedro O Miranda ◽

Sonia Sayalero ◽

Esther Alza ◽

...

Keyword(s):

Continuous Flow ◽

Optical Purity ◽

Batch Process ◽

Packed Bed ◽

Catalyst Loading ◽

Residence Times ◽

Packed Bed Reactors ◽

Effective Catalyst ◽

Fold Reduction

The application of polystyrene-immobilized proline-based catalysts in packed-bed reactors for the continuous-flow, direct, enantioselective α-aminoxylation of aldehydes is described. The system allows the easy preparation of a series of β-aminoxy alcohols (after a reductive workup) with excellent optical purity and with an effective catalyst loading of ca. 2.5% (four-fold reduction compared to the batch process) working at residence times of ca. 5 min.

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