Biological wastewater treatment
Powdered HOK® dosed into the biological stage buffers the conditions microorganisms experience, producing compact, fast-settling sludge.
Learn moreActivated lignite, supplied with expertise
Proven carbon
for cleaner water.
CGS Carbon supplies HOK® Activated Lignite — a cost-effective sorbent manufactured by RWE in Germany — to wastewater, industrial, and environmental treatment operations.
- RWEManufactured in Germany from Rhenish lignite
- 4 gradesFrom extremely fine powder to 5 mm granules
- ISO 9001Produced under a certified quality system
- BirchtechBacked by a clean air and water technology group
The product
Meet HOK® Activated Lignite.
A porous carbon sorbent produced from Rhenish lignite in a rotary hearth furnace — the Herdofen that gives the product its name.
HOK® differs from most conventional activated carbons in both how it is manufactured and how it behaves. Rather than a separate carbonization and activation sequence applied to purchased feedstock, it is produced continuously from freshly mined lignite at the source. The manufacturer has established it over decades as a cost-effective sorbent and filter material in environmental technology.
- Purpose-built for treatment — developed for water and gas cleaning duty, not adapted from another use
- Matched to your process — four particle-size grades for dosing, suspension, and fixed-bed service
- Consistently produced — sampled multiple times daily and analyzed by the manufacturer's laboratory
Granular grades
Fixed beds & filters
Robust granules, 1.25–5 mm.
Powder grades
Dosing & suspension duty.
4 gradesPowder to 5 mm granules
Water
Biological and adsorptive wastewater treatment, industrial effluent, landfill leachate, and drinking water filtration — the applications where most of our customers start.
- Biological dosing
- Fixed bed
- Leachate
Explore water applications
Gas
The duty where HOK® built its industrial reputation: separating pollutants from waste gas and flue gas streams so operators can meet strict emissions limits.
- Waste gas
- Flue gas
- Emissions limits
Explore gas applications
Applications
Where HOK® goes to work.
Every application below is drawn from the manufacturer's published documentation. We don't list uses HOK® hasn't been documented in.
Adsorptive treatment
For substances that resist biological degradation — applied in stirred suspension or packed into fixed-bed filters.
Learn moreIndustrial wastewater & leachate
Adsorptive treatment of industrial sewage and landfill leachate carrying variable, demanding contaminant loads.
Learn moreDrinking water filtration
Granular grades used as filter material where a robust, consistent carbon medium is required.
Learn moreWaste gas & flue gas cleaning
Separating pollutants from gas streams to support compliance with strict emissions limits for hazardous substances.
Learn moreNot sure where you fit?
Describe your stream, your existing treatment train, and your compliance targets. We'll tell you honestly whether HOK® is worth evaluating.
Talk to an expert
Why CGS Carbon
A supplier that knows the product.
We do one thing: put a proven European sorbent in the hands of North American treatment operators, with the responsiveness of a specialist rather than a catalog.
Reliable supply
Material produced at industrial scale under a certified quality system, with logistics arranged around how your site actually receives it.
Technical familiarity
We know the grades, how they behave in biological and adsorptive service, and which questions to settle before you trial anything.
Backed by Birchtech
Part of an environmental technology group whose business is clean air and clean water — not a trading desk that happens to carry carbon.
Claims we can support
We cite the manufacturer's documentation and tell you where the data ends. Your regulators will ask; the answer should hold up.
How it works
Adsorption, in three steps.
The mechanism is straightforward — which is part of why it has held up in industrial service for decades.
A porous carbon framework
Activation in the rotary hearth furnace develops an internal pore structure, giving the material a large internal surface area relative to its mass.
Contaminants adhere
As water or gas passes the particles, dissolved and entrained substances accumulate on that surface. Larger organic molecules adhere preferentially.
Cleaner stream leaves
Loaded sorbent is separated or retained within the treatment stage, and the treated stream continues through your process.
A sorbent is only as good as the supply behind it and the advice in front of it.
Get started
Let's talk about your treatment needs.
Whether you're specifying a sorbent for a new treatment line or looking for a dependable source of HOK®, tell us what you're working on. We'll respond with grade guidance, manufacturer documentation, and supply options.