ARNSBERG MUNICIPAL UTILITIES
Case Study: Reactivation with Sustainable Coconut-Based Make up Carbon
Arnsberg Municipal Utilities (Stadtwerke Arnsberg GmbH) is a public utility company owned by the city of Arnsberg, located in the Sauerland region of North Rhine-Westphalia, Germany. The company operates a 431-kilometre distribution network and supplies local households with high-quality drinking water from four water extraction and treatment plants. A portion of the drinking water is sourced from the Arnsberg Water Supply Association’s Langel waterworks, operated by Arnsberg Municipal Utilities. Another of the four waterworks sites is situated in Möhnebogen. The raw water is primarily drawn from the rivers Möhne and Ruhr.
Ensuring top-quality drinking water — without the need for additional household filtration — is one of the company’s core commitments. Alongside water quality, sustainability and environmental protection are central to its operations.
The Challenge
As early as 2006, elevated concentrations of per- and polyfluoroalkyl substances (PFAS, also referred to as PFCs or PFTs) were detected in the Möhne and Ruhr rivers. The cause was traced back to regional soil contamination. In response, Arnsberg Municipal Utilities promptly implemented a provisional granular activated carbon (GAC) filtration system at the Möhnebogen waterworks.
By 2011, a permanent installation with four GAC filters, each holding 37.5 m³, went into operation. The system used a coal-based activated carbon supplied by another manufacturer.
One year later, the Langel waterworks of the Arnsberg Water Supply Association was equipped with a similar GAC system, again using a coal-based activated carbon.
However, this product led to quality issues — specifically, the leaching of heavy metals into the treated drinking water. This meant a volume of water was unsuitable to be supplied for drinking use. This was a circumstance that required additional operational measures.
The goal was, therefore, to eliminate heavy-metal leaching while adopting a more sustainable solution.
The Solution
Fast forward 2017 and working with Jacobi teams, drawing on previous experience and driven by the desire for a more environmentally friendly alternative, Arnsberg Municipal Utilities decided to use AquaSorb CS a coconut-shell-based activated carbon from the Jacobi Group portfolio, at the Langel waterworks. The conditions — particularly a dissolved organic carbon (DOC) level1 below 1 mg/L in the raw water — were ideal for this application.
After shifting to AquaSorb CS, Langel Waterworks solved the heavy metal leaching issue whilst using more sustainable base media. Möhnebogen continued to use a re-agglomerated, coal-based activated carbon, AquaSorb 6300, material as their makeup whilst monitoring performance.
Additional to activated carbon at both the Möhnebogen and Langel waterworks, the spent media undergoes our reactivation process every two years. Jacobi Carbons Service Europe GmbH arranges this under the ReSorb Solo concept at the company’s reactivation plant in Premnitz, Brandenburg.
The Results
After several years of operation, Arnsberg Municipal Utilities was able to systematically compare adsorption behaviour and filter run times at both waterworks. Meanwhile, PFAS levels in the rivers decreased consistently, and the general focus of water treatment in the area expanded towards the removal of trace organic micropollutants also.
In 2019, Arnsberg Municipal Utilities and Jacobi Group evaluated whether the coal-based activated carbon at the Möhnebogen waterworks could be replaced by a coconut-based alternative. Key factors in this decision were the positive operational results from the Langel waterwork, the excellent reactivation properties of the coconut-based carbon, and its significantly lower carbon footprint.
A subsequent SAC2541 analysis (spectral absorption coefficient at 254 nm) of the raw water showing a DOC2 level of 1.3 mg/L confirmed the suitability of coconut-based activated carbon. As a result of this testing, the Möhnebogen waterworks has been gradually converted to AquaSorb CS, replacing the coal-based makeup carbon previously used. The makeup proportion initially started at 25% and was later increased to 30%. This is typical of our ‘renewable reactivation’ process.
Today, Arnsberg Municipal Utilities benefit not only from a reliable and high-performance filtration media, but also from a tangible contribution to environmental and climate protection.
The use of coconut-shell-based activated carbon, together with the established reactivation concept, significantly improves the sustainability of drinking water treatment without compromising quality or operational safety.
“We’ve had excellent experiences with coconut-based activated carbon. This solution perfectly aligns with our company’s sustainability philosophy. In terms of both availability and lead time, Jacobi’s AquaSorb CS is the better choice for us.”
Thomas Kroll, Technical Director at Arnsberg Municipal Utilities
If you would like to find out more about Jacobi solutions for water treatment along with our reactivation service then feel free to contact your local Jacobi representative here.
- SAK254 (Spectral Absorption Coefficient): UV absorption at 254 nm, indicating the presence of organic compounds in water.
- DOC (Dissolved Organic Carbon): A measure of organic carbon dissolved in water.