Related Experiment Video
Updated: Jun 6, 2026
08:13
A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Development of simultaneous partial nitrification, anammox and denitrification (SNAD) process in a sequential batch
Chien-Ju Lan1, Mathava Kumar, Chih-Cheng Wang
1Institute of Environmental Engineering, National Chiao Tung University, 1001 University Road, Hsinchu City 30010, Taiwan, ROC.
Bioresource Technology
|December 3, 2010
Summary
The simultaneous partial nitrification, anammox, and denitrification (SNAD) process effectively removes over 96% of ammonium-nitrogen and 87% of COD. The system shows resilience to HRT changes but is sensitive to drastic shifts in DO, pH, and temperature.
Area of Science:
- Environmental Engineering
- Microbial Ecology
Background:
- Wastewater treatment faces challenges in nitrogen and organic matter removal.
- Simultaneous partial nitrification, anammox, and denitrification (SNAD) offers an integrated approach.
- Optimizing SNAD process conditions is crucial for efficient nutrient removal.
Purpose of the Study:
- To investigate the influence of hydraulic retention time (HRT) on the SNAD process performance.
- To evaluate the system's response to shock loading and variations in operating parameters.
- To model total nitrogen removal based on stoichiometric relationships.
Main Methods:
- Development of a SNAD process in a sequential batch reactor (SBR).
- Systematic variation of hydraulic retention time (HRT) and monitoring of removal efficiencies.
- Assessment of system sensitivity to changes in dissolved oxygen (DO), pH, and temperature.
- Stoichiometric modeling of total nitrogen (TN) removal.
Main Results:
- Optimal NH(4)(+)-N and COD removal efficiencies of approximately 96% and 87% were achieved at 9 d HRT.
- The SNAD system demonstrated marginal decreases in removal efficiencies with reduced HRT (3 d) or tripled loading rate.
- Significant reductions in NH(4)(+)-N and COD removal occurred under drastic decreases in DO, pH, and temperature.
- Sensitivity analysis indicated the system's response to operational shocks.
Conclusions:
- The SNAD process is a robust method for simultaneous removal of ammonium and COD, with HRT being a key operational parameter.
- The process exhibits sensitivity to sudden environmental changes, highlighting the need for stable operating conditions.
- Anammox, coupled with partial nitrification, is the primary driver of total nitrogen removal, contributing 85-87%, while denitrification accounts for 7-9%.
More Related Videos
15:19Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
11:31Continuously-stirred Anaerobic Digester to Convert Organic Wastes into Biogas: System Setup and Basic Operation
Published on: July 13, 2012
Related Concept Videos
01:29Bioreactor Design and Operational System
Bioreactors are engineered vessels designed to cultivate microorganisms under controlled conditions for industrial bioprocessing. They maintain sterility and allow precise regulation of pH, temperature, oxygen, and nutrient levels to optimize microbial growth and metabolite production. Bioreactors range from small laboratory units of 1 liter to industrial systems holding up to 500,000 liters, though only about 75% of their volume is actively used for fermentation. The remaining headspace...
01:26Microbes and the Nitrogen Cycle
The nitrogen cycle is a complex biogeochemical process critical to maintaining the balance of nitrogenous compounds in ecosystems. This cycle involves multiple microbial-mediated transformations through which nitrogen changes oxidation states, supporting essential ecological functions and contributing to plant and microbial growth.Nitrogen Fixation and AmmonificationNitrogen fixation initiates the cycle by converting inert atmospheric nitrogen (N₂) into bioavailable ammonia (NH₃), a process...
01:14Batch vs Continuous Culture
Fermentation is a foundational biotechnological process used to produce pharmaceuticals, biofuels, enzymes, and food additives. Among industrial strategies, batch and continuous fermentation are the two most widely applied. Although both rely on microbial conversion of substrates into desired products, they differ markedly in operation, productivity, and suitability for specific applications.Batch fermentation occurs in a closed system in which nutrient media and inoculum are added at the...
01:18Bioreactor Controls-II
In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...
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...
01:30Microbial 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.