Reducing micropollutants in water

Wastewater treatment plants (WWTPs) are sources of organic micropollutants in waterways, making it important to improve the efficiency of removal processes and reduce their environmental impact. In Weißenburg, Germany, a pilot project is comparing the effectiveness of granular activated carbon and sand filters to boost filtration efficiency after ozonation.

DynaSand filters were installed in two process streams to see which method best removed a number of micropollutants. A standard removal rate of trace substances without a fourth purification stage is around 20%.

“This trial has produced some very positive data and the DynaSand filters have been integral to the process. Their compact footprint and simple integration enabled the pilot project to start producing incredible results quickly.”

Sonja Winandi, Team Leader, Technical Support Treatment at Sulzer

The challenge
Micro-pollutants pose a major challenge to wastewater treatment plants as national and local legislation is tightened. Traditional filtration and screening methods, including tertiary treatment, remove only around 20% of trace substances, which means additional process are required.

This poses challenges in terms of space and cost to install the new equipment. The pilot project in Germany needed to establish the effectiveness of a new filtration process.

The solution
Nordic Water, a Sulzer brand, designed DynaSand filters to offer a compact and cost-effective solution that can incorporate sand or granular activated carbon (GAC). Installing four filters in two parallel streams enabled the effectiveness of the two options to be assessed.

The additional sand filtration improved efficiency considerably, but effectiveness varied from 76-90%. The activated carbon filter delivered a more consistent 92% removal rate. As a result, the customer upgraded all units to the carbon system, enabling optimum effectiveness.

Customer benefit
Establishing the most effective process for removing micropollutants requires expert support. Trials such as this are key to understanding the most appropriate solution for a particular site. Each treatment plant has its own unique challenges, and the right solution can ensure new environmental standards can be achieved.

As more wastewater treatment plants integrate better filtration technology, so water quality will improve and levels of micropollutants will drop