Various electron donors for biological nitrate removal: A review
1Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, PR China.
The Science of the Total Environment
|July 2, 2021
Summary
Biological denitrification effectively removes nitrate (NO₃⁻) pollution using various electron donors. Biodegradable polymers, hydrogen, and sulfur show promise for efficient nitrate removal in water and wastewater treatment.
Area of Science:
- Environmental Science
- Microbiology
- Water Treatment Engineering
Background:
- Nitrate (NO₃⁻) pollution is a significant global environmental concern.
- Biological denitrification offers an efficient and cost-effective method for nitrate removal from water and wastewater.
- This process relies on denitrifying microorganisms and requires an electron donor.
Purpose of the Study:
- To review and analyze various electron donors used in biological denitrification.
- To classify denitrification processes based on electron donor types (heterotrophic and autotrophic).
- To compare the performance, costs, and environmental impacts of different denitrification strategies.
Main Methods:
- Literature review of biological denitrification processes and electron donors.
- Classification of denitrification into heterotrophic (organic donors) and autotrophic (inorganic donors).
- Summary and comparison of microbial communities, performance data, costs, and environmental impacts.
Main Results:
- Heterotrophic denitrification utilizes diverse organic compounds (e.g., acetate, glucose, polylactic acid).
- Autotrophic denitrification employs inorganic donors like hydrogen (H₂), sulfur compounds, and iron species.
- Biodegradable polymers, H₂, and sulfur-mediated denitrification are identified as promising future applications.
Conclusions:
- The choice of electron donor significantly influences the efficiency and applicability of biological denitrification.
- Both heterotrophic and autotrophic pathways offer viable solutions for nitrate remediation.
- Further research and application of specific electron donors like biodegradable polymers and H₂/sulfur are encouraged for sustainable nitrate removal.
Related Concept Videos
01:22Inorganic Nitrogen Assimilation
186
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...
186
01:15Metabolism of Chemolithotrophs
367
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.
367
01:20Overview of Nitrogen Metabolism
10.2K
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
10.2K
01:28Microbial Nutrition
595
Organisms exhibit remarkable metabolic diversity, categorized based on how they acquire energy and carbon. These strategies enable survival in various ecological niches and are essential for maintaining energy flow and nutrient cycling within ecosystems.Energy and Carbon SourcesOrganisms are classified as phototrophs or chemotrophs based on energy acquisition. Phototrophs use light as their energy source, while chemotrophs rely on oxidizing chemical compounds. Further differentiation arises...
595
01:49The Nitrogen Cycle
57.6K
Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of nitrogen on Earth is nitrogen gas, which cannot be used by most animals and plants. Thus, nitrogen gas must first be converted into a usable form by nitrogen-fixing bacteria before it can be cycled through other living organisms. The use of nitrogen-containing fertilizers and animal waste products in human agriculture has greatly influenced the...
57.6K
01:202° Amines to N-Nitrosamines: Reaction with NaNO2
4.8K
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
4.8K