Related Experiment Video
Updated: Jul 9, 2026
08:13
A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Accelerated algal-bacterial granulation through synergistic physical-ionic stimulation: start-up efficiency and
Duanyang Shangguan1, Libin Yang1, Cheng Hou1
1College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; State Key Laboratory of Water Pollution Control and Green Resource Recycling, Shanghai 200092, China.
Bioresource Technology
|July 7, 2026
Summary
Combining a static magnetic field with magnesium ions significantly speeds up algal-bacterial granular sludge formation for wastewater treatment. This sustainable approach enhances nutrient removal and sludge stability, reducing costs and overcoming key industrial deployment challenges.
Area of Science:
- Environmental Science and Engineering
- Biotechnology
- Materials Science
Background:
- Algal-bacterial granular sludge (ABGS) offers a sustainable path for carbon-neutral wastewater treatment.
- Current industrial use of ABGS is hindered by slow granulation and unstable aggregates.
- Existing methods for enhancing ABGS struggle to balance rapid formation with structural integrity cost-effectively.
Purpose of the Study:
- To investigate the synergistic effect of a static magnetic field (SMF) and Mg2+ on accelerating ABGS formation.
- To analyze the impact of this coupled strategy on the physicochemical properties and microbial community of ABGS.
- To evaluate the techno-economic feasibility of the SMF-Mg2+ approach for wastewater treatment.
Main Methods:
- Application of a weak static magnetic field (5 mT) coupled with Mg2+ stimulation.
- Monitoring granulation time, nutrient removal efficiency (COD, TN, PO43--P), and granule settleability (SVI30).
- Characterization of extracellular polymeric substances (EPS), microbial community structure, and surface interaction energetics using Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory.
Main Results:
- Granulation time reduced by 44.0% to 14 days.
- High removal efficiencies achieved: COD (95.1%), TN (78.6%), PO43--P (84.3%).
- Improved granule characteristics: average diameter (2.8 mm), settleability (SVI30 = 55.2 mL/g).
- SMF-Mg2+ coupling enhanced protein-dominated EPS, enriched functional bacteria (e.g., Thauera), and reduced surface energy barriers, promoting aggregation.
- Techno-economic assessment indicated a potential 59% reduction in operational expenditure (OPEX).
Conclusions:
- The synergistic SMF-Mg2+ strategy significantly accelerates ABGS granulation and enhances stability.
- This approach optimizes wastewater treatment performance, achieving high nutrient removal and excellent settleability.
- The physical-ionic stimulation offers a scalable and cost-effective solution to overcome ABGS start-up limitations, promoting sustainable wastewater management.
Related Concept Videos
01:06Coagulation
Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...
01:25Biofuels
The microbial conversion of organic matter into biofuels holds potential as a renewable energy source. Among biofuel sources, microalgae are recognized as a highly efficient and adaptable feedstock for biodiesel production, owing to their rapid biomass accumulation, elevated lipid productivity, and capacity to proliferate in diverse aquatic systems, including freshwater, marine, and wastewater habitats. Unlike terrestrial crops, microalgae do not compete for land and can achieve significantly...
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...
01:21Green Algae
Green algae, also referred to as chlorophytes, are different from red algae in having the chloroplasts containing chlorophylls a and b, which give them their distinct green hue. However, they lack phycobiliproteins, preventing them from developing the red or blue-green pigmentation seen in red algae. In terms of photosynthetic pigment composition, green algae closely resemble plants and share a close evolutionary relationship with them. Taxonomically Green algae belong to Phylum Chlorophyta in...