Sewage Sludge Drying System

  • Up to 45% subsidized acquisition costs

  • Save up to 75% on energy costs

  • 100% planning reliability thanks to premium after-sales service

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The disposal of sewage sludge is one of the biggest challenges in municipal and industrial wastewater treatment. With a HARTER sewage sludge drying system, you significantly reduce sludge volume, lower transport and disposal costs, and simultaneously meet environmental regulations.

The innovative heat pump drying operates exhaust-free, hygienically, and extremely energy-efficiently – ideal for municipal wastewater treatment plants, industrial, and chemical facilities.

How HARTER develops individual solutions for every requirement is shown in: How Solutions for Heat Pump Dryers are Created.
An overview of the technology can be found in: Energy-Saving Drying with Heat Pumps.

Do you require a custom solution and/or would you like to test the drying process beforehand?

Development with practical tests in our in-house development center

We are an innovation-driven team and welcome new challenges. HARTER tests your custom solution in the technical center under realistic conditions, optimizes the parameters, and documents the results transparently. Please contact us – we would be pleased to provide you with a non-binding consultation!

Contact our experts now +49 8383 9223‑210 or submit the contact form
2000

Drying systems

in over 20 countries stand for our quality

100

Employees

from all areas ensure a high level of vertical integration

+ 35

Years of experience

in the development of innovative drying systems

Sewage Sludge Drying System – Operating Principle and Process Advantages

After mechanical dewatering, sewage sludge often still contains 60–80% water. Only through targeted thermal drying does the sludge become transportable, storage-stable, and significantly easier to dispose of or thermally recover.

The HARTER heat pump drying operates in a closed air circuit:
The air is dehumidified, heated, and recirculated over the material – completely without exhaust air losses. The system reuses the energy recovered in the heat pump multiple times, drastically reducing electricity consumption.

Your advantages at a glance:

  • Up to 70% less energy consumption than with hot air processes
  • Exhaust-free, low-odor operation
  • Uniform residual moisture levels at low temperatures (30–75 °C)
  • low-maintenance, durable technology
  • Stable process control independent of ambient air

How HARTER modularly expands systems and designs them for higher throughputs is shown in: Expanding Capacities with Heat Pump Dryers.

Sewage Sludge Drying Systems

Sewage Sludge Drying System – Applications, Designs, and Integration

The HARTER sewage sludge drying systems are suitable for both municipal and industrial applications. Whether for municipal wastewater treatment plants, chemical plants, paper mills, or electroplating facilities – HARTER delivers customized systems for every requirement.

Typical Application Areas:

  • Municipal and industrial wastewater treatment plants
  • Sludges from the chemical, food, or pharmaceutical industries
  • Electroplating and metal hydroxide sludges
  • Mixed sludges from industrial processes

System Types:

  • Batch and Tray Dryers for batch processes
  • Belt and Tunnel Dryers for continuous throughputs
  • Special Systems with customer-specific air guidance and automation

The drying temperature is precisely adapted to the material. Due to the exhaust-free design, neither odors nor pollutant emissions are generated – a major advantage for densely built-up locations or indoor operation.

In its in-house technical center, HARTER tests original sludges under real conditions. Air guidance, temperature, humidity, and residual water content are analyzed. These data form the basis for a validated, operationally reliable series system.

The Process

We dry with dry air and deliver it to the right places: A perfect interplay of air preparation and air guidance provides you with the best possible drying result.

Interface: Airgenex® Dehumidification Technology / Dryer – Moist air is extracted from the drying chamber and supplied to the dehumidification unit.

The pre-cooler pre-cools the air in a first stage. This significantly reduces the compressor’s energy consumption.

Moisture condenses on the fins of the air cooler and drains out of the drying system via the drip tray and condensate drain.

The cooled, dehumidified air is warmed up without additional energy by means of a pre-heater.
The air heater warms the air to the required process temperature.

The process air fan ensures the necessary air exchange between the Airgenex® dehumidification technology and the drying chamber.

Now, the dry, unsaturated air is guided into the drying chamber, where it absorbs the product’s moisture. Thus, the cycle is closed.

Efficiency that pays off.

Our HARTER drying systems save up to 75% CO₂ and are up to 45% governmentally funded.

Reliable – Competent – Long-term

Service that thinks ahead – for years to come

With the HARTER After-Sales Service, you secure a reliable and efficient drying solution for the long term. Whether it’s maintenance, spare parts supply, or technical adjustments – we support your system throughout its entire life cycle and ensure that it delivers optimal results at all times.

Performance Service

Optimal performance through our “all-round carefree package”

Custom Service

Flexible for changing requirements

Expert Service

Fast assistance in case of failure

Lifetime Service

So that the quality is always right

Sewage Sludge Drying System – Sustainability, Economic Efficiency, and Environmental Footprint

HARTER’s heat pump technology is not only efficient but also makes a significant contribution to resource conservation. Thanks to the closed air circuit and heat recovery, almost all energy remains within the system.

Sustainable advantages:

  • Low CO₂ emissions due to high energy efficiency
  • No combustion or exhaust air emissions
  • Reduction of disposal volume by up to 70%
  • Short payback periods due to low operating costs
  • Eligible technology (e.g., BAFA, EU programs)

Many HARTER customers combine drying with heat recovery or photovoltaics. This further increases energy self-sufficiency and climate neutrality. Find more about related applications on Industries.

What our customers say

Not convinced yet? Our customers are thrilled!

“Sometimes it is better to say nothing and let your customers speak for themselves.”
– Regina Mader, Managing Director

“For several decades, we have been using a sludge dryer from Harter in our electroplating shop and are very satisfied with it. The technology and service are reliable and have helped us save a lot of money on disposal.”

Daniel Hutter
Verzinkerei Kriessern AG

“BK Giulini GmbH has been working successfully with Harter GmbH for around 20 years. We are very satisfied with both the dryer technology and the reliability of the complete system. Based on these positive experiences and the very good service, we invested in another drying system of this type in 2023.”

Dimitri Baumbach
ICL Ladenburg / BK Giulini GmbH (ICL Group)

“In our waste incineration plant, we have saved an enormous amount of money by drying our heavy metal-containing hydroxide sludge. The system technology is sustainable and easy to maintain. In retrospect, the investment was a very good decision.”

Stefan Ringmann
KVA Linth

FAQ – Frequently Asked Questions about Sewage Sludge Drying Systems

The air is dehumidified and reheated. This closed circuit prevents energy losses and ensures uniform drying to the desired residual moisture content.

Depending on the material type and target residual moisture, between 30 °C and 75 °C. This allows the sludge to dry efficiently, without thermal decomposition or odor formation.

Compared to hot air or gas processes, savings typically amount to 50–70%. This significantly reduces operating costs.

Since no exhaust air is generated, no moist or contaminated air streams are released to the outside. Odors remain in the system and are bound in the condensate.

Yes. HARTER develops modular systems that can be easily connected to existing dewatering equipment (e.g., chamber filter presses).

Via sensors and digital process control. The parameters are individually validated for each sludge type in the technical center.

Yes. Due to their high energy efficiency, they meet the criteria of many funding programs at national and European levels.

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