DynaSand Carbon

Continuous GAC filtration for public water utilities, industrial and clean water treatment
DynaSand Carbon is Nordic Water’s continuous backwash granular activated carbon (GAC) filter for high-flow municipal fourth stage, industrial and clean water treatment. It combines the proven continuous filtration principle of DynaSand with the adsorption performance of activated carbon to remove micropollutants, natural organic matter (NOM), colour, COD, PFAS*, residual oxidants (such as chlorine, chloramine and ozone) and other trace organics from water and wastewater.

*PFAS removal is dependent on the selected carbon grade and local design requirements.

DynaSand Carbon is designed for treatment sites requiring operational efficiency in challenging operating conditions: high flows, varying loads and limited space. It provides continuous carbon filtration without the downtime associated with conventional backwash GAC filters.

Talk to a filtration specialist

Read about the Baden-Baden micropollutant removal case

Download the Baden-Baden micropollutant removal case here

DynaSand Carbon at a glance

• Continuous GAC filtration – no scheduled backwash cycles or production stops

• High-flow capability – suited to municipal wastewater quaternary treatment, drinking water and industrial effluent polishing

• Efficient carbon use – continuous media movement helps maintain adsorption performance and extend media life

• Compact footprint – ideal for both new builds and retrofit projects with limited space

• Supported globally – application and lifecycle support via Nordic Water and the wider Sulzer network

Carbon filtration for micropollutant removal

DynaSand Carbon provides continuous carbon filtration for micropollutant removal in municipal and industrial wastewater, as well as clean water applications. By combining up-flow filtration with continuous media movement, it delivers stable adsorption of pharmaceuticals, personal care products and other trace organics without the downtime associated with conventional backwash filters.

This makes DynaSand Carbon a practical option where:

• Micropollutant limits are tightening or emerging

• Upgrades are needed on existing biological treatment plants

• Operators require a robust, continuous solution rather than a batch-style filtration step

Micropollutant reduction is only one part of what the system can do, but it is a key driver in many current projects and regulations.

How DynaSand Carbon works

DynaSand Carbon uses the established DynaSand continuous filtration principle, with granular activated carbon as the filter media.

1. Up-flow filtration and adsorption
   Water enters at the bottom of the filter and flows upwards through the GAC bed. Dissolved organics, micropollutants and other contaminants are adsorbed onto the carbon surface as the water passes through.

2. Continuous media movement
   A small flow of air and water lifts a portion of the carbon bed via an internal airlift. This movement happens continuously while the filter is in operation.

3. Internal washing
   At the top of the airlift, carbon passes through an internal washer where entrained solids and fines are removed. Clean carbon then returns to the top of the bed.

4. Stable long-term operation
   Because the media is continuously refreshed, DynaSand Carbon operates without the need for scheduled backwash cycles or separate backwash pumps and tanks.

Key technical characteristics

• Filtration mode: continuous up-flow GAC filtration

• Media: granular activated carbon (several grades can be selected to match the application)

• Operation: fully automatic, continuous media regeneration

Typical applications: quaternary polishing, clean water treatment, industrial water and wastewater treatment

Public authority wastewater fourth stage treatment

• Micropollutant polishing following activated sludge clarification, MBBR or MBR

• Fourth stage treatment before discharge to sensitive receiving waters

• Water reuse schemes, where consistent trace organics control is required

DynaSand Carbon can be installed downstream of existing clarification and filtration stages or integrated as a new quaternary step.

Clean water and drinking water

• Natural organic matter (NOM) reduction to help manage disinfection by-product formation.

• Taste and odour removal, including compounds such as geosmin and MIB, naturally occurring compounds that cause earth or musty tastes in drinking water.

• Pesticide and herbicide adsorption for surface and groundwater sources.

• PFAS treatment, when designed with appropriate GAC grades and contact times.

• Removal of residual oxidants such as free chlorine, chloramine and ozone to protect downstream membranes, ion exchange resins and other sensitive equipment.

DynaSand Carbon can complement existing coagulation–clarification–filtration–disinfection trains where additional organic and oxidant control is required, particularly before RO and NF membranes.

Industrial water and wastewater treatment

• Colour and COD reduction in sectors such as textiles, pulp and paper, food and beverage, pharmaceuticals and chemicals.

• Trace organics removal prior to discharge or reuse.

• Process water polishing, including removal of residual chlorine, chloramine and ozone as pre-treatment before reverse osmosis and other membrane or resin systems.

Continuous carbon filtration is particularly suited to industrial plants where flows are high, downtime is costly and influent conditions - including oxidant levels - can vary.

Practical design points

When applying DynaSand Carbon, we typically evaluate:

• Influent conditions – suspended solids, organic load – and any target contaminants, the presence of upstream treatment steps and residual oxidants

• Treatment goals – micropollutants, COD, colour, NOM, PFAS, taste and odour, oxidant removal for membrane protection, and overall effluent or product water quality targets

• Empty bed contact time (EBCT) – sized to provide the necessary adsorption for target contaminants

• Hydraulic loading – to maintain stable bed behaviour and head loss

• Media selection and replacement strategy – carbon type, regeneration or replacement intervals, and long-term OPEX

These details are usually developed in collaboration with plant operators or designers and may be supported by pilot testing where appropriate.

A collaborative approach to filtration projects

Choosing the right carbon filtration technology is rarely just a product decision. Nordic Water works with:

• Public water utilities upgrading wastewater treatment or drinking water quality

• Industrial operators facing tighter discharge licences or internal sustainability targets

• Consulting engineers and EPCs who need reliable, documented solutions that integrate into broader process designs

Experience, expertise and support

• DynaSand continuous filtration has been used in thousands of installations worldwide over several decades.

• Our teams bring application knowledge from municipal wastewater, drinking water and industrial process water projects.

• As part of Sulzer, we can align filtration with pumping, mixing, aeration, screening, flotation and sludge handling solutions where needed.

Our objective is to provide realistic performance expectations, robust designs and long-term support.

Baden-Baden WWTP​

The Baden-Baden wastewater treatment plant added a fourth treatment stage for municipal micropollutant removal, using DynaSand Carbon continuous GAC filtration to support current and future discharge requirements.

Nordic Water supplied a full-stream granular activated carbon filtration process. The installation uses 120 DynaSand Carbon filters arranged in 12 concrete basins, providing a total filter area of 600 m² and treating an average flow of approximately 4,700 m³/h.

Project highlights

• Fourth treatment stage for municipal micropollutant removal

• Full-stream GAC filtration using 120 DynaSand Carbon filters

• Designed for full-flow operation, including wet-weather conditions

• Reported 95.5% micropollutant removal efficiency in the first year

• Low-maintenance continuous filtration with stable, reliable operation

Read the case study

DynaSand filters solve micropollutant problems

Download the Baden-Baden micropollutant removal case here

FAQ – DynaSand Carbon (Continuous GAC Filtration)

Q1. What is DynaSand Carbon and how does it work?
DynaSand Carbon is a continuous granular activated carbon (GAC) filter that uses an internal airlift column to move and clean the media and elute foreign debris continuously. Water flows upward through the carbon bed, where organics, micropollutants and oxidants are adsorbed.

Q2. How does DynaSand Carbon remove micropollutants?
Micropollutants are adsorbed onto the activated carbon as the water passes through the bed. The continuous movement of the carbon maintains adsorption efficiency and prevents the breakthrough issues seen in static GAC beds, especially under variable loading.

Q3. Can DynaSand Carbon remove chlorine, chloramine and ozone?
Yes. Activated carbon naturally removes free chlorine, chloramine and ozone through catalytic and adsorptive reactions. This makes DynaSand Carbon suitable as pre-treatment before RO, NF or ion exchange systems, where oxidants must be removed to protect membranes and resins.

Q4. When should I use DynaSand Carbon instead of conventional GAC filters?
DynaSand Carbon is preferred when:

• Flows are high or continuous

• Downtime for backwashing is not acceptable

• Influent quality varies

• Space constraints limit the use of multiple GAC vessels

• Continuous oxidant or organics polishing is required

Conventional GAC is suitable for long EBCT, low-flow and stable operating conditions.

Q5. What contaminants can DynaSand Carbon remove?
Typical targets include:

• Micropollutants (pharmaceuticals, personal care products, pesticides*)

• Natural organic matter (NOM)

• Taste and odour compounds

• Colour and COD

• Residual oxidants (chlorine, chloramine, ozone)

• PFAS* (with specific GAC grades and design EBCT)

*Design-dependent; influent quality and carbon selection determine performance.

Q6. Can DynaSand Carbon be used in drinking water treatment?
Yes. DynaSand Carbon can provide NOM reduction, pesticide removal, taste/odour control and oxidant removal in surface water and groundwater systems. It can operate as a primary GAC step or as a polishing step downstream of clarification and filtration.

Q7. Is DynaSand Carbon suitable for industrial wastewater?
Yes. It is commonly used for:

• Colour and COD reduction

• Trace organics polishing

• Membrane pre-treatment (oxidant removal)

• Water reuse projects

Industries include pulp & paper, textiles, food & beverage, pharmaceuticals and chemicals.

Q8. How often does activated carbon need to be replaced?
Carbon replacement intervals depend on:

• EBCT

• Influent organic load

• Target removal objectives

• Carbon grade

• Flow variability

Continuous filtration extends media life by reducing fouling and maintaining adsorption performance.

Q9. Does DynaSand Carbon require backwash equipment?
No. The filter continuously regenerates carbon using an internal airlift and washer. This eliminates the need for:

• Backwash pumps

• Backwash tanks

• Backwash sequences

• Downtime

Q10. Can DynaSand Carbon integrate with existing treatment trains?
Yes. It is typically installed downstream of:

• Biological treatment

• Clarification

• DynaDisc or DynaCloth filtration

• Sand filtration

• Oxidation (ozone, UV, AOP)

It can also serve as a polishing step before membranes or reuse.

Q11. What is EBCT? (Empty Bed Contact Time)
EBCT is the theoretical time water spends in the carbon bed, based on the carbon volume and flow rate. It is a standard design parameter for PAC/GAC systems in municipal and industrial water treatment.