Heat exchangers for energy recovery from sludge and water

Biogas production plants and water treatment plants

In water treatment plants and in biogas production plants, a lot of heat is created. Our energy recovery heat exchangers allow to reuse this heat. 

Our sustainable sludge/sludge, sludge/water and air/water heat exchangers are especially designed to recover the maximum amount of heat. As a result, this reused heat leads to a substantial reduction in production costs and an increase in operating efficiency. Task Environmental Engineering is your contact within the Benelux for the Swedish Läckeby heat exchangers. These high quality heat exchangers have been installed in water purification plants and biogas installations for over 20 years. Läckeby heat exchangers features:
  • High quality
  • Insensitive to clogging
  • very compact, with a low footprint
  • High heat recovery
  • a long service life
  • easy maintenance

Heat exchangers for sludge/water and sludge/sludge applications

Our sludge heat exchangers are used for highly viscous substances, such as water treatment sludge, digestion sludge and sludge from biogas installations. These are compact units, insensitive to clogging, with a high heat transfer and large flow capacity. Moreover, maintenance and inspection are very easy. Two versions are available: the sludge-water heat exchanger and the sludge-sludge heat exchanger.

What distinguishes a Läckeby heat exchanger from other heat exchangers?

  • Unique patented design especially for sludge
  • High heat transfer
  • Large flow capacity
  • Minimal pressure loss
  • Patented turning chamber facilitating quick inspection
  • Clogging insensitive
  • Compact (stackable) and easy to install units
  • Homogenous sludge temperature thanks to good mixing in the turning chambers
  • Insulated housing to prevent energy loss
  • Extremely maintenance-friendly

Energy recovery from sludge

In the digestion process of animal manure, organic waste and sludge from water treatment plants, a large amount of heat is generated. Our robust, high quality heat exchangers allow you to make the best use of the available heat and save money in many applications.

So, this excess heat can be used to pre-heat the digestion substrate or to provide hot water. Läckeby offers heat exchangers for high viscosity sludge. Our heat exchangers ensure efficient heat transfer with a minimal risk of clogging.

Two connected sludge/water units on a closed water circuit allow to recover energy from hot sludge. And secondly, this recovered energy is used to preheat the incoming sludge. A closed water circuit excludes the risk of contamination and provides the necessary flexibility to control the process temperature.

Sludge applications

  • direct heating or cooling of raw or digested sludge on the feed line
  • heating or cooling of digested sludge by digestion or pasteurisation circulation
  • Energy recovery from hot sludge
  • Agro-industrial digesters
  • Organic waste digesters
  • Biogas recovery from landfills

Wastewater applications

  • cooling of wastewater in biological water treatment
  • energy recovery from wastewater before discharge
  • biogas production from sewage
  • industrial wastewater treatment plants

Available types of heat exchangers

Heat exchangers for energy reuse from sludge and water


Sludge-to-sludge heat exchangers recover the heat from digested sludge to transfer it to the raw sludge, through a closed piping system. Such a design excludes the risk of contamination. Circular sludge channels provide a large transfer zone, reducing pressure losses. The patented open chamber rotation system allows higher heat transfer. Furthermore, this robust and modular product features high reliability, a high heat transfer and low maintenance requirements.


Sludge-to-water heat exchangers recover heat from sludge to transfers it to the water. Modular Läckeby heat exchangers are compact, easy to install and easy maintenance. The circular sludge channels and patented open chamber rotation system ensure high heat transfer, low pressure losses and a minimum risk of clogging.

Heat exchanger sludge water

Case studies

Heating of the digester substrate in biogas installations

Our sludge/sludge heat exchanger is extremely suitable for heating the digester substrate in anaerobic digestion plants and biogas plants (biogas upgrading). In numerous large and small biogas plants, these heat exchangers have been used with proven efficiency. The digester substrate originates mostly from agriculture and catering.

Surplus heat, produced during the digestion process and the upgrading of the biogas, can be used to preheat the biogas substrate. Preheated biogas substrate allows to speed up the digestion process and reduce the energy consumption.

Preheating hot water circuits

These sludge-water and air-water heat exchangers are ideally suited for preheating water circuits. As a result, this pre-heated water can be used anywhere in the factory or premises. For example, water treatment in laundries or other industries where large amounts of hot water are required. Läckeby heat exchangers are very versatile, you can also use them as cost-saving applications for air conditioning or heating. More about our air-water heat exchangers.

Custom made solutions

Task/Läckeby Sweden produce and install all necessary infrastructure to make your heat exchanger installation as efficient as possible. Our heat exchangers are fully customised for seamless integration into your production process. The installation can be designed as a complete turnkey unit or you can choose to integrate the heat exchanger yourself. Furthermore, we offer you a complete range of shaftless screw conveyors, shaftless piston presses and septic receiving units. 

Installation, maintenance and services

We provide efficient delivery and installation of each heat exchanger. You can also always contact us for the following services:

Heat exchangers


Technical specifications


A selection of our realisations worldwide. Some projects were realised by the mother house Läckeby Sweden, some by our colleagues on all continents, some by Task. A click on the pictures below is providing more information about the projects.