Boosting micropollutant removal from wastewater

The first long-term trial in Germany of a continuous granular activated carbon (GAC) filter using ferric salts dosing immediately before filtration has delivered conclusive results. The pilot project used three DynaSand carbon filters, two with coagulant dosing and one control. All three filters were filled with approximately five tonnes of GAC.

The results showed that it is possible to achieve a Ptot level of <0.2 mg/l, which would pass some of the most stringent water quality standards in the world.

“These pilot projects are crucial to demonstrating how the latest filter technology performs in real-world applications. This long-term trial has shown how existing infrastructure can be upgraded to meet new water quality standards.”

Sonja Winandi, Sulzer

The challenge
To design and build three filters to demonstrate the effectiveness of ferric dosing in conjunction with continuous GAC filters. As a pilot project, comprehensive monitoring and data recording were also required to ensure accurate information was available for inspection

The solution
A long-term pilot project to optimize the removal of micropollutants from wastewater using ferric dosing upstream of the DynaSand carbon filters. The process is optimized by wash cycles that do not require the filtration process to stop.

Continuous monitoring of sink velocity and bed movement was achieved by the integrated SandCycle system, which enabled real-time bed tracking.

Customer benefit
The project demonstrated the benefits of introducing coagulants upstream of the GAC filters to achieve an excellent reduction of phosphorous levels as well as high removal rates of other micropollutants. The 18-month project duration also highlighted the reliability of the filters’ performance in the long-term.

Based on the data gathered, it was shown that it is possible to achieve some of the most stringent water quality standards for phosphorous using this filter arrangement.