Robotic Cleaning of Slow Sand Filters in Waterworks

About the project

Slow sand filtration is a proven, chemical-free and energy-efficient technology for drinking water treatment. The process relies on biological treatment in the upper layer of the filter bed and is widely valued for its robustness and sustainability. However, routine cleaning requires filters to be drained and the top layer of sand to be removed, which can disturb the biological processes and reduce production capacity.

This project aims to develop and demonstrate a novel robotic method for underwater cleaning of slow sand filters. By performing cleaning while the filter remains water-filled, the approach seeks to reduce operational disturbances, minimise sand removal and support a faster recovery of the filter biology after cleaning.

A robot prototype will be developed, tested and refined through iterative full-scale trials at a drinking water treatment plant. Filters cleaned using the robot will be compared with conventionally cleaned filters to evaluate impacts on head loss, microbiological performance and operational efficiency. 

The project also investigates how robotic underwater cleaning can contribute to more resource-efficient operation and provide a practical method that can be implemented by drinking water utilities. Project activities include prototype development in Year 1, followed by testing, monitoring and evaluation during Years 2 and 3.

Benefits

For drinking water utilities, the new method has the potential to reduce water losses, lower resource consumption and improve operational stability. If filters can return to normal biological performance more quickly after cleaning, the need for energy, chemicals and reserve treatment capacity may be reduced. The technology may also help increase drinking water production during periods of high demand. 

In addition, increased automation can improve the working environment by reducing manual operations. For society, the solution offers an opportunity to strengthen the resilience of drinking water supply systems and support more sustainable use of water resources.

Project partners

Stockholm Vatten och Avfall (SVOA) is responsible for overall project management and coordination of the field trials. The contact person at SVOA is Lars-Erik Hägglund, Development Engineer. E-mail: lars-erik.hagglund@svoa.se. Telephone: 08-522 120 00

WEDA is responsible for the development of the robot prototype. The contact person at WEDA is Klas Lange, klas@weda.se 

RISE Research Institutes of Sweden is responsible for evaluation, dissemination of results and coordination of the reference group

Reference group

A reference group will be involved throughout the project to provide feedback and support knowledge exchange. Invitations are extended to water utilities operating slow sand filters, as well as other interested stakeholders.

Current members of the reference group include:

• Hjo Municipality
• Jönköping Municipality
• Norrköping Municipality
• Tekniska Verken i Linköping AB
• Trollhättan Energi AB

The reference group is expected to expand during the project as additional water utilities and stakeholders join the initiative.