Related Experiment Video
Updated: May 23, 2026
15:19
Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
Autotrophic denitrification for nitrate and nitrite removal using sulfur-limestone
Weili Zhou1, Yejue Sun, Bingtao Wu
1School of Environmental Science and Engineering, Shanghai Jiaotong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, China. weilizhou@sjtu.edu.cn
Journal of Environmental Sciences (China)
|March 22, 2012
Summary
Sulfur-limestone effectively removes nitrate and nitrite in autotrophic denitrification. Optimal conditions include specific hydraulic retention times and temperatures, with microorganisms facilitating the conversion to nitrogen.
Area of Science:
- Environmental Science
- Microbiology
- Water Treatment Engineering
Background:
- Nitrate and nitrite contamination in water poses environmental and health risks.
- Autotrophic denitrification offers a sustainable biological approach for nitrogen removal.
- Sulfur-limestone is a potential substrate for supporting denitrifying microbial communities.
Purpose of the Study:
- To evaluate the efficacy of sulfur-limestone in an upflow biofilter for autotrophic denitrification.
- To determine the impact of influent concentrations, hydraulic retention time (HRT), and temperature on removal efficiency.
- To investigate the microbial mechanisms involved in nitrate and nitrite reduction.
Main Methods:
- Laboratory-scale upflow biofilter experiments were conducted.
- Synthetic water with varying nitrate and nitrite concentrations (10-100 mg N/L) was used.
- Batch tests were performed to analyze influencing factors.
- Molecular analysis was employed to identify microbial roles.
Main Results:
- High removal rates (approx. 90%) were achieved for low concentrations (10-40 mg N/L) at 3-hour HRT and 20-25°C.
- Significant removal (50%) was observed even at lower temperatures (5-10°C) with the same HRT.
- Higher concentrations (70-100 mg N/L) required longer HRT for effective removal.
- Batch tests confirmed influent concentration, HRT, and temperature as key factors.
Conclusions:
- Sulfur-limestone is an effective medium for autotrophic denitrification of nitrate and nitrite.
- Denitrification efficiency is significantly influenced by operational parameters like HRT and temperature.
- The same microorganisms appear responsible for both nitrate and nitrite reduction, potentially within the same cell.
More Related Videos
08:05Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
07:14Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx
Published on: December 20, 2016
Related Concept Videos
01:20Sulfur Assimilation
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to become...
01:29Microbes and the Sulfur Cycle
Sulfur is a vital element in Earth's biogeochemical systems. It transitions through various inorganic states, including sulfate (SO₄²⁻), elemental sulfur (S⁰), and sulfide (S²⁻). Abiotic and biological mechanisms across oxic and anoxic environments intricately mediate these transformations. Sulfate, the most oxidized form of sulfur, is predominantly stored in rocks, marine sediments, and oceanic waters, acting as a long-term reservoir in the global sulfur cycle.In oxic environments,...
01:15Metabolism of Chemolithotrophs
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation. However, because inorganic electron donors...
01:19Acid Mine Drainage
Mining activities that disturb sulfide-rich rocks, particularly those containing pyrite (FeS₂), initiate a cascade of geochemical and microbiological processes with serious environmental implications. When exposed to air and water, pyrite undergoes oxidation, releasing sulfate, ultimately forming sulfuric acid and mobilizing heavy metals into surrounding water systems. This phenomenon, known as acid mine drainage (AMD), results in low pH waters laden with toxic elements that threaten aquatic...
01:22Inorganic Nitrogen Assimilation
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme nitrate reductase...
01:25Microbial Bioremediation of Uranium
Microorganisms play a critical role in the transformation and immobilization of uranium in contaminated environments through four main pathways: bioreduction, biosorption, bioaccumulation, and biomineralization. These mechanisms reduce uranium’s toxicity and prevent its migration through groundwater systems, offering sustainable approaches for in situ bioremediation.Bioreduction of UraniumBioreduction is driven by anaerobic bacteria such as certain strains of Geobacter and Shewanella, which use...