Sundern Municipal Utilities (Stadtwerke Sundern) is a public utility operated by the town of Sundern, located in the Hochsauerland region. Among its responsibilities is the provision of local drinking water. This includes the extraction of raw water from springs, deep wells and a reservoir, as well as its treatment, storage, and distribution to end consumers. The utility is also a member of the Hochsauerland Water Association (WVH).
Water supply in the service area is ensured through a modern, technically advanced infrastructure. Seven extraction facilities provide the required water, which is stored in 17 elevated reservoirs with a total capacity of 7,730 cubic metres. The pipe network extends across 303.6 kilometres, reliably delivering drinking water to 8,357 domestic connections.
Introducing Granular Activated Carbon
In 2007, a granular activated carbon (GAC) filtration stage was installed at This consisted of three parallel GAC filters, each with a capacity of 20 m³, initially filled with a coal-based activated carbon.
The GAC filtration stage plays a critical role in removing chlorinated hydrocarbons (CHCs), which are occasionally detected in the raw water in trace amounts (< 2 µg/l), as well as other dissolved organic contaminants. Acting as a “policing” filter, it captures variable soluble pollutants that can enter the raw water supply, particularly after heavy rainfall.
The Challenge
In recent years the activated carbon in use was sporadically reactivated, with fresh coal-based carbon used as makeup. In 2021, an analysis carried out by the IWW “Rheinisch-Westfälisches Institut für Wasser” revealed that the spent carbon had only limited remaining adsorption capacity and poor reactivation potential.
As a result, IWW recommended a full carbon replacement be carried out. It identified coconut shell-based activated carbon as a suitable alternative – offering excellent compatibility with the local raw water composition and treatment goals at the Sundern plant, while also contributing to reduced CO₂ emissions performance.
The Solution
Building on these findings, Jacobi Group was commissioned in 2023 to replace the spent coal-based carbon with fresh AquaSorb™ activated carbon made from coconut shells.
Since the replacement, this new carbon has been in full operation.
The Result
Switching to coconut shell-based activated carbon has proven highly effective for maintaining the safeguard function of the GAC filtration stage. As advised by IWW, Sundern Municipal Utilities has significantly reduced its global warming potential (GWP) as a result of this change.
Activated Carbon Performance Testing
Here at Jacobi we also offer a comprehensive analysis service for carbon at our in-house laboratories. These tests assess reactivation potential and include pilot reactivation trials to give a realistic indication of future performance after treatment.
Our Process Solutions Team works closely with clients to develop tailored carbon management strategies – whether through planned reactivation cycles or complete media replacement. Additionally, we evaluate whether more sustainable or better-suited activated carbon types from our portfolio might offer technical or environmental advantages for the specific application. Get in touch for more information on our testing services.
Reactivation – The key to sustainable activated carbon management.
In many cases, regular reactivation of spent carbon is a more sustainable approach than complete replacement. When reprocessed correctly, much of the original performance can be restored – saving both resources and costs.
Even when replacement is necessary, spent GAC does not have to be discarded. In line with circular economy principles, Jacobi offers to take back used carbon for re-use or alternative processing, where feasible. This helps protect both the environment and client budgets through responsible material stewardship.
Jacobi Group provides a full reactivation service, including the safe and compliant collection of spent carbon, followed by the return of the reactivated product. Our own reactivation facilities uphold the highest quality standards, and our transport and logistics processes prioritise short, resource-efficient routes – underlining our commitment to sustainability.