Related Experiment Video
Updated: Jun 3, 2026
06:10
Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge
Published on: September 26, 2016
Microbially induced hydroxyapatite improves simultaneous nitrogen and phosphorus removal in aerobic granular sludge
Fan Yang1, Gonglei Wang1, Shanshan Xu1
1College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
Bioresource Technology
|June 1, 2026
Summary
Biologically induced phosphorus precipitation (BIPP) enhances nutrient removal in aerobic granular sludge (AGS) systems. This process, forming hydroxyapatite (HAP), improves both nitrogen and phosphorus removal by optimizing microbial metabolism and carbon allocation.
Area of Science:
- Environmental Microbiology
- Wastewater Treatment
- Biogeochemistry
Background:
- Aerobic granular sludge (AGS) shows promise for simultaneous nitrogen and phosphorus removal.
- Competition for organic carbon among microbial communities limits deep nutrient removal in AGS.
- Biologically induced phosphorus precipitation (BIPP) offers a strategy to enhance phosphorus removal.
Purpose of the Study:
- To investigate the formation mechanisms and ecological impacts of BIPP in AGS systems.
- To compare BIPP performance under aerobic (O_SBR) and anaerobic-aerobic (AO_SBR) regimes.
- To elucidate the relationship between mineral accumulation, microbial metabolism, and pollutant removal.
Main Methods:
- Implementation of BIPP in AGS systems under O_SBR and AO_SBR operational modes.
- Analysis of precipitate composition, focusing on hydroxyapatite (HAP) formation.
- Evaluation of nutrient removal efficiencies (nitrogen and phosphorus).
- Assessment of carbon, nitrogen, and phosphorus fluxes and microbial metabolic shifts.
Main Results:
- Hydroxyapatite (HAP) was the dominant precipitate in both O_SBR and AO_SBR systems.
- Distinct HAP induction mechanisms were observed: localized pH elevation via denitrification (O_SBR) and favorable ionic conditions from polyphosphate-accumulating organisms (AO_SBR).
- BIPP significantly improved phosphorus removal (approx. 75% in O_SBR, >99% in AO_SBR).
- Mineral accumulation correlated with enhanced electron flux to denitrification and improved nitrogen removal.
Conclusions:
- BIPP effectively enhances phosphorus removal in AGS systems through HAP precipitation.
- Distinct mechanisms drive HAP formation under different operational regimes, highlighting the adaptability of AGS.
- Mineral accumulation is coupled with microbial metabolism, optimizing carbon allocation for simultaneous nitrogen and phosphorus removal in AGS.
Keywords:
Aerobic granular sludgeBiologically-induced phosphorus precipitationMicroenvironment regulationOperational modeSimultaneous nitrogen and phosphorus removalMore Related Videos
Related Concept Videos
01:30Microbial Wastewater Treatment
Microbial communities in aquatic ecosystems play a key role in the natural breakdown of contaminants introduced through domestic and industrial effluents. Acting as biological catalysts, these microbes change and mineralize a wide range of organic and inorganic pollutants under different redox conditions.In oxygen-rich surface waters, aerobic heterotrophs lead organic matter breakdown, using oxygen as the terminal electron acceptor to efficiently oxidize substrates to carbon dioxide and water.
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...
01:30Environmental Applications of Microorganisms
Microorganisms play a pivotal role in maintaining ecosystem balance by recycling essential elements such as carbon, nitrogen, and phosphorus, as well as supporting processes like bioremediation, wastewater treatment, and biofuel production.Microbes in Elemental CyclesIn the carbon cycle, microorganisms decompose organic matter, releasing carbon dioxide via aerobic respiration. This carbon dioxide is subsequently used by photosynthetic organisms to synthesize organic compounds, closing the...
01:26Microbial Bioremediation of Hydrocarbons
Bioremediation is an environmentally sustainable process that employs living organisms—primarily microorganisms—to degrade or neutralize pollutants from contaminated environments. In oil spills and hydrocarbon pollution, bioremediation involves the use of hydrocarbon-degrading bacteria to transform toxic compounds into less harmful substances. This approach leverages natural microbial metabolic processes and is considered both cost-effective and ecologically favorable compared to physical or...
01:30Biological Treatment of Effluent and Waste Water
Biological wastewater treatment relies on the metabolic activity of microorganisms to remove pollutants from sewage. In modern treatment systems, this process is organized into sequential stages that progressively reduce solid material, dissolved organic matter, and microbial contamination. Each stage plays a distinct role in improving water quality and preparing the effluent for safe discharge or reuse.Primary and Secondary TreatmentPrimary treatment is a physical process that removes large...
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...