Comparison of particulate pyrite autotrophic denitrification (PPAD) and sulfur oxidizing denitrification (SOD) for treatment of nitrified wastewater

2016 ◽  
Vol 75 (1) ◽  
pp. 239-246 ◽  
Author(s):  
Shuang Tong ◽  
Laura C. Rodriguez-Gonzalez ◽  
Chuanping Feng ◽  
Sarina J. Ergas
Keyword(s):  
Packed Bed ◽  
Product Formation ◽  
Electron Donors ◽  
Autotrophic Denitrification ◽  
Reduced Sulfur Compounds ◽  
N Removal ◽  
Sulfur Oxidizing ◽  
Reduced Sulfur ◽  
Carry Over ◽  
Set Up

The use of reduced sulfur compounds as electron donors for biological denitrification has the potential to reduce chemical and sludge disposal costs as well as carry-over of organic carbon to the effluent that often occurs with heterotrophic denitrification. Although a number of prior studies have evaluated sulfur oxidizing denitrification (SOD), no prior studies have evaluated particulate pyrite autotrophic denitrification (PPAD) in continuous flow systems. Bench-scale upflow packed bed reactors (PBRs) were set up to compare denitrification rates, by-product production and alkalinity consumption of PPAD and SOD. At an empty bed contact time of 2.9 h, average NO3−-N removal efficiencies were 39.7% and 99.9% for PPAD and SOD, respectively. Although lower denitrification rates were observed with PPAD than SOD, lower alkalinity consumption and reduced sulfur by-product formation (SO42−, S2− and SO32− plus S2O32−) were observed with PPAD. Furthermore, higher denitrification rates and lower by-product production was observed for SOD than in prior studies, possibly due to the media composition, which included sand and oyster shells. The results show that both pyrite and elemental sulfur can be used as electron donors for wastewater denitrification in PBRs.

Simultaneous biological removal of sulphide and nitrate by autotrophic denitrification in an activated sludge system

2006 ◽  
Vol 53 (12) ◽  
pp. 91-99 ◽  
Author(s):  
I. Manconi ◽  
A. Carucci ◽  
P. Lens ◽  
S. Rossetti
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Electron Donor ◽  
Product Formation ◽  
Fish Analysis ◽  
Autotrophic Denitrification ◽  
Biological Removal ◽  
N Removal ◽  
Activated Sludge Reactor ◽  
Denitrification Process

The feasibility of an autotrophic denitrification process in an activated sludge reactor, using sulphide as the electron donor, was tested for simultaneous denitrification and sulphide removal. The reactor was operated at nitrate (N) to sulphide (S) ratios between 0.5 and 0.9 to evaluate their effect on theN-removal efficiency, the S-removal efficiency and the product formation during anoxic oxidation of sulphide. One hundred per cent removal of both nitrate and sulphide was achieved at a NLR of 7.96 mmol N·L−1·d−1 (111.44 mg NO3−-N·L−1·d−1) and at a N/S ratio of 0.89 with complete oxidation of sulphide to sulphate. The oxygen level in the reactor (10%) was found to influence the N-removal efficiency by inhibiting the denitrification process. Moreover, chemical (or biological) oxidation of sulphide with oxygen occurred, resulting in a loss of the electron donor. FISH analysis was carried out to study the microbial population in the system.

scholarly journals “Candidatus Chlorobium masyuteum,” a Novel Photoferrotrophic Green Sulfur Bacterium Enriched From a Ferruginous Meromictic Lake

2021 ◽  
Vol 12 ◽  
Author(s):  
Nicholas Lambrecht ◽  
Zackry Stevenson ◽  
Cody S. Sheik ◽  
Matthew A. Pronschinske ◽  
Hui Tong ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Tca Cycle ◽  
Green Sulfur Bacteria ◽  
Sulfur Compounds ◽  
Electron Donors ◽  
Anoxygenic Phototrophic Bacteria ◽  
Reduced Sulfur Compounds ◽  
Sulfur Bacteria ◽  
Green Sulfur ◽  
Reduced Sulfur

Anoxygenic phototrophic bacteria can be important primary producers in some meromictic lakes. Green sulfur bacteria (GSB) have been detected in ferruginous lakes, with some evidence that they are photosynthesizing using Fe(II) as an electron donor (i.e., photoferrotrophy). However, some photoferrotrophic GSB can also utilize reduced sulfur compounds, complicating the interpretation of Fe-dependent photosynthetic primary productivity. An enrichment (BLA1) from meromictic ferruginous Brownie Lake, Minnesota, United States, contains an Fe(II)-oxidizing GSB and a metabolically flexible putative Fe(III)-reducing anaerobe. “Candidatus Chlorobium masyuteum” grows photoautotrophically with Fe(II) and possesses the putative Fe(II) oxidase-encoding cyc2 gene also known from oxygen-dependent Fe(II)-oxidizing bacteria. It lacks genes for oxidation of reduced sulfur compounds. Its genome encodes for hydrogenases and a reverse TCA cycle that may allow it to utilize H2 and acetate as electron donors, an inference supported by the abundance of this organism when the enrichment was supplied by these substrates and light. The anaerobe “Candidatus Pseudopelobacter ferreus” is in low abundance (∼1%) in BLA1 and is a putative Fe(III)-reducing bacterium from the Geobacterales ord. nov. While “Ca. C. masyuteum” is closely related to the photoferrotrophs C. ferroooxidans strain KoFox and C. phaeoferrooxidans strain KB01, it is unique at the genomic level. The main light-harvesting molecule was identified as bacteriochlorophyll c with accessory carotenoids of the chlorobactene series. BLA1 optimally oxidizes Fe(II) at a pH of 6.8, and the rate of Fe(II) oxidation was 0.63 ± 0.069 mmol day–1, comparable to other photoferrotrophic GSB cultures or enrichments. Investigation of BLA1 expands the genetic basis for phototrophic Fe(II) oxidation by GSB and highlights the role these organisms may play in Fe(II) oxidation and carbon cycling in ferruginous lakes.

scholarly journals Oxidation of Molecular Hydrogen by a Chemolithoautotrophic Beggiatoa Strain

2016 ◽  
Vol 82 (8) ◽  
pp. 2527-2536 ◽  
Author(s):  
Anne-Christin Kreutzmann ◽  
Heide N. Schulz-Vogt
Keyword(s):  
Molecular Hydrogen ◽  
Microbial Mats ◽  
Hydrogen Oxidation ◽  
Natural Populations ◽  
Sulfur Compounds ◽  
Electron Donors ◽  
Reduced Sulfur Compounds ◽  
Physical Damage ◽  
Content Type ◽  
Reduced Sulfur

ABSTRACTA chemolithoautotrophic strain of the familyBeggiatoaceae,Beggiatoasp. strain 35Flor, was found to oxidize molecular hydrogen when grown in a medium with diffusional gradients of oxygen, sulfide, and hydrogen. Microsensor profiles and rate measurements suggested that the strain oxidized hydrogen aerobically when oxygen was available, while hydrogen consumption under anoxic conditions was presumably driven by sulfur respiration.Beggiatoasp. 35Flor reached significantly higher biomass in hydrogen-supplemented oxygen-sulfide gradient media, but hydrogen did not support growth of the strain in the absence of reduced sulfur compounds. Nevertheless, hydrogen oxidation can provideBeggiatoasp. 35Flor with energy for maintenance and assimilatory purposes and may support the disposal of internally stored sulfur to prevent physical damage resulting from excessive sulfur accumulation. Our knowledge about the exposure of natural populations ofBeggiatoaceaeto hydrogen is very limited, but significant amounts of hydrogen could be provided by nitrogen fixation, fermentation, and geochemical processes in several of their typical habitats such as photosynthetic microbial mats and submarine sites of hydrothermal fluid flow.IMPORTANCEReduced sulfur compounds are certainly the main electron donors for chemolithoautotrophicBeggiatoaceae, but the traditional focus on this topic has left other possible inorganic electron donors largely unexplored. In this paper, we provide evidence that hydrogen oxidation has the potential to strengthen the ecophysiological plasticity ofBeggiatoaceaein several ways. Moreover, we show that hydrogen oxidation by members of this family can significantly influence biogeochemical gradients and therefore should be considered in environmental studies.

Alkalinity requirements and the possibility of simultaneous heterotrophic denitrification during sulfur-utilizing autotrophic denitrification

2000 ◽  
Vol 42 (3-4) ◽  
pp. 233-238 ◽  
Author(s):  
E.-W. Kim ◽  
J.-H. Bae
Keyword(s):  
Packed Bed ◽  
Autotrophic Denitrification ◽  
Leachate Treatment ◽  
N2o Production ◽  
Packed Bed Reactors ◽  
N Concentration ◽  
N Removal ◽  
Sulfur Layer ◽  
Denitrification Activity ◽  
Heterotrophic Denitrification

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.

Managing total reduced sulfur emissions at a Canadian kraft pulp mill

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 265-272 ◽  
Author(s):  
ROHAN BANDEKAR ◽  
JIM FREDERICK ◽  
JAROSLAV STAVIK
Keyword(s):  
Direct Contact ◽  
Black Liquor ◽  
Pulp Mill ◽  
Packed Bed ◽  
Average Value ◽  
Emission Limit ◽  
Total Reduced Sulfur ◽  
Reduced Sulfur ◽  
Air Ingress ◽  
Solids Content

This study addresses the challenges a dissolving-grade pulp mill in Canada faced in 2014 in meeting its total reduced sulfur (TRS) gas emission limit. These emissions from the recovery boiler exit are controlled by passing the boiler exit gas through a TRS scrubber system. The mill employs a cyclonic direct contact evaporator to concentrate black liquor to firing solids content. The off-gases from the direct contact evaporator flow to the effluent gas control system that consists of a venturi scrubber, a packed bed scrubber, and a heat recovery unit. Emissions of TRS greater than the regulated limit of 15 ppm were observed for a 4-month period in 2014. The level of emissions measured during this period was significantly higher than about 12 ppm, the expected average value based on historic experience. The problem persisted from mid-June 2014 until the annual mill shutdown in October 2014. The main TRS components detected and the performance of the Teller scrubber in capturing them are examined. Other potential causes for these emissions are identified, including mechanical problems such as broken packing in the TRS packed bed scrubber, broken baffle plates in the scrubber, and cyclone evaporator leaks causing air ingress. Repairs were carried out during the mill shutdown, which eliminated the TRS emissions problem.

scholarly journals An evaluation of the Kemtek 1000 sample processor

1988 ◽  
Vol 10 (1) ◽  
pp. 37-42 ◽  
Author(s):  
M. J. Wheeler ◽  
Linzi Waiters
Keyword(s):  
Probe System ◽  
Carry Over ◽  
Set Up ◽  
Accuracy Speed ◽  
Better Than ◽  
The Way

The Kemtek 1000 Sample Processor has been evaluated for precision, accuracy, speed and reliability. Precision was better than 1.0% at all volumes tested and accuracy within ±5%. A l00-tube assay could be set up within 15 min when patient specimens plus two reagents were sampled using a two probe system. Carry-over could be reduced to <0.01% by using a sufficient number of wash steps, the latter being related to the assay requirements. Evidence was found for adsorption of protein to the probe tubing but inaccuracies due to this could be reduced by introducing wash steps between samples. Problems over 12 months have been minor and quickly resolved. The authors were pleased with the way the processor performed and their staffhave confidence in leaving it to set up their assays.

Granulation of sulfur-oxidizing bacteria for autotrophic denitrification

2016 ◽  
Vol 104 ◽  
pp. 507-519 ◽  
Author(s):  
Weiming Yang ◽  
Hui Lu ◽  
Samir K. Khanal ◽  
Qing Zhao ◽  
Liao Meng ◽  
...  
Keyword(s):  
Autotrophic Denitrification ◽  
Sulfur Oxidizing ◽  
Sulfur Oxidizing Bacteria
Sign in / Sign up

Export Citation Format

Share Document