Water treatment is both a science and an art—balancing chemical performance, operational efficiency, and environmental responsibility. One of the most critical steps in the treatment process is coagulation, where coagulants are used to destabilize and remove suspended solids, organic matter, and other impurities. But achieving optimal results requires more than just adding a coagulant—it demands a deep understanding of the water matrix, coagulant chemistry, and dosing strategies.
At Gulbrandsen Technologies, we’ve partnered with treatment plants around the world to help improve performance through smart, data-driven coagulant use. In this blog, we share key insights and best practices gathered from real-world applications to help utilities maximize the effectiveness of their coagulation processes.
Why Optimization Matters
Effective coagulation leads to:
- Improved turbidity and color removal
- Lower residual metal concentrations
- Reduced sludge production
- Cost savings through lower chemical and energy use
However, underdosing or overdosing can lead to poor floc formation, increased residuals, and downstream filtration challenges. This is why optimizing coagulant type and dosage is essential for achieving both regulatory compliance and operational efficiency.
1. Start with a Thorough Water Quality Analysis
Every water source is different. Surface water, groundwater, and industrial effluents each present unique challenges. Key parameters that influence coagulant performance include:
- Turbidity
- Alkalinity
- pH
- Organic content (e.g., TOC, DOC)
- Temperature
Case Insight:
A municipal water plant treating a high-organic-content river water struggled with seasonal changes. After switching to a blended coagulant tailored for variable organics and adjusting for pH swings, they saw a 30% reduction in turbidity and improved filter run times.
2. Select the Right Coagulant
There is no one-size-fits-all solution. Coagulant selection depends on both water chemistry and treatment goals. Common coagulant types include:
- Aluminum-based (e.g., alum, polyaluminum chloride)
- Iron-based (e.g., ferric chloride, ferric sulfate)
- Blended or polymer-enhanced coagulants (offering broader performance range and lower residuals)
Best Practice: Evaluate coagulants based on:
- Performance (turbidity and TOC removal)
- Residual metal levels
- Compatibility with existing infrastructure
- Sludge handling and disposal needs
At Gulbrandsen, we offer a portfolio of customized coagulants, including low-residual aluminum formulations and high-performance ferric blends—each tested and refined in real-world conditions.
3. Optimize Dosing Through Jar Testing and Real-Time Monitoring
Laboratory jar tests simulate treatment performance and are essential for determining the optimal dose under varying water conditions. Complement this with online monitoring systems to adjust dosing dynamically.
Case Insight:
An industrial facility using a fixed alum dose experienced inconsistent effluent quality. After implementing inline turbidity and pH sensors to drive real-time dosing, they achieved consistent clarity and reduced chemical use by 20%.
4. Maintain Ideal pH and Mixing Conditions
pH significantly impacts coagulant effectiveness. Most aluminum and iron-based coagulants work best in the 6.0–7.5 pH range.
Also, ensure:
- Rapid mixing immediately after dosing for uniform distribution.
- Gentle flocculation to promote strong, settleable flocs.
Tip: Coagulant performance can be improved with the use of coagulant aids such as polymers, which help strengthen flocs and enhance sedimentation.
5. Track Performance and Continuously Improve
Optimization isn’t a one-time process. Track KPIs like:
- Finished water turbidity
- Filter run times
- Chemical consumption
- Sludge volume
Use this data to refine your chemical program and identify areas for further savings or improvements.