Last Updated on April 30, 2025 by Kevin Chen
What are the common types of mixers used in wastewater treatment?
1. Submersible Mixers
Mixing Series: This series is suitable for agitating liquids containing suspended solids in municipal/industrial wastewater treatment processes. It typically uses multi-stage motors with a direct-drive structure (low energy consumption and high efficiency, functioning like an energy-saving expert). Impellers are precision-cast or stamped for high accuracy, strong thrust, and compact design. Application example: In primary sedimentation tanks of small WWTPs, these submersible mixers thoroughly blend sewage with settled sludge, preventing bottom sedimentation that compromises treatment effectiveness.
Low-speed Propulsion Series: Designed for aeration/anaerobic tanks in municipal/industrial WWTPs, facilitating water circulation and optimized flow/aeration during nitrification, denitrification, and phosphorus removal. Employs helical gear reducers with low-power/low-RPM motors. Large-diameter impellers from polyurethane and cast aluminum alloy ensure high strength and corrosion resistance. Large-scale WWTP aeration tanks achieve uniform aeration distribution for enhanced treatment efficiency.
2. Paddle Mixers
Available as flat-blade and angled-blade configurations:
- Flat-blade: Two straight blades with a diameter-to-height ratio of 4 – 10, operating at 1.5 – 3m/s (minimal radial flow).
- Angled-blade: Blades bent 45° – 60° to generate axial flow. Simple structure for mixing low-viscosity liquids and dissolving/suspending solid particles. It is ideal for rapid chemical mixing in dosing systems when handling low-viscosity reagents.
3. Turbine Mixers
2-4 straight/curved blades mounted on horizontal discs (outer diameter/width/height ratio: 20:5:4). Creates turbulent radial flow at 3 – 8m/s for gas-liquid dispersion and liquid-phase reactions. Effective for processes like oxygen aeration in wastewater treatment, efficiently dissolving gases (max liquid viscosity: 25Pa·s).
4. Anchor Mixers
Contoured blades match tank walls (0.5 – 1.5mm clearance) to scrape viscous residues. Operates at 0.5 – 1.5m/s for high-viscosity Newtonian/pseudoplastic fluids (≤200Pa·s). Critical in viscous wastewater/sludge treatment to prevent wall adhesion and ensure consistent mixing.
5. Helical Ribbon Mixers
Equal ribbon diameter/pitch ratio. Specifically designed for laminar flow mixing of high-viscosity liquids (200 – 500Pa·s). Essential for homogenizing high-concentration sludge and viscous wastewater streams.
What Are the Key Points for Selecting Mixers?
- Process Requirements: Biological processes (e.g., activated sludge) require mixers like submersibles/turbines to blend sewage-sludge mixtures and maintain dissolved oxygen. Chemical processes (e.g., coagulation) demand rapid coagulant mixing using paddle mixers.
- Wastewater Properties:
- High viscosity → Anchor/helical ribbon mixers
- Corrosiveness → Stainless steel construction
- High solids → Self-cleaning impellers (submersible mixers)
- Performance Factors: Evaluate mixing intensity, efficiency, energy consumption, and reliability. Large-scale plants require high-power, high-efficiency, and durable mixers (e.g., heavy-duty submersible models).
- Tank Configuration:
- Shape compatibility (rectangular vs. circular tanks)
- Depth coverage (verify mixer immersion range)
- Volume requirements (determine multiple units or high-power units)
What Are the Application Scenarios of Mixers?
- Chemical Dosing Systems: Small paddle or submersible mixers ensure rapid dissolution and uniform blending of chemicals.
- Coagulation Tanks: Paddle mixers optimize flocculant-wastewater contact for accelerated floc formation.
- Anoxic/Anaerobic Tanks: Propulsion-type submersible mixers maintain sludge recirculation and create optimal microbial habitats.
- Sludge Holding Tanks: Submersible mixers or compatible equipment prevent sedimentation and maintain pumpable sludge consistency.
The selection and application of wastewater treatment mixers require meticulous evaluation of all factors. Only through comprehensive analysis can optimal mixer solutions ensure efficient, stable operations and contribute to environmental sustainability.
The above information is about the How to Choose Wastewater Treatment Mixers. If you still have related questions about , please feel free to contact SPERTA.
Shanghai SPERTA Environmental Technology Co., Ltd. has specialized in producing water treatment products for many years. The company has its own MBR membrane technology, a complete technical team, and pre-sales and after-sales service. If you have any needs, please feel free to contact us.
