Heat exchangers for energy recovery from sludge and water

In water treatment plants and in biogas production plants, a lot of heat is created. Heat that we can reuse. Our sustainable sludge/sludge, sludge/water and air/water heat exchangers are specially designed to recover the maximum amount of heat. This reuse of 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 Läckeby heat exchangers from Sweden. The high quality heat exchangers have been installed in water purification plants and biogas installations for over 20 years. These top quality, compact heat exchangers have a high heat recovery, a long life span and are 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. They are compact units, insensitive to clogging, have a high heat transfer and large flow capacity. Moreover, maintenance and inspection are very easy. There are two versions available: the sludge-water heat exchanger and the sludge-sludge heat exchanger.

What distinguishes a Läckeby heat exchanger from others?

  • 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 flows

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.

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. These heat exchangers ensure efficient heat transfer with minimal risk of clogging.

Two connected sludge/water units on a closed water circuit allow the recovered energy from hot sludge to be used to preheat the incoming sludge. The 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


The sludge-to-sludge heat exchanger recovers 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. This robust and modular product is highly reliability, has a high heat transfer and low maintenance requirements.


The sludge-to-water heat echanger recovers heat from sludge and transfers it to the water. The modular heat exchangers in the Läckeby range are compact, easy to install and also easy to maintain. 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). These heat exchangers have been used with proven efficiency in numerous large and small biogas plants, mostly using digester substrate from agriculture and catering.

The surplus heat, produced during the digestion process and the upgrading of the biogas, can be used to preheat the biogas substrate in order to speed up the digestion process and reduce the energy consumption.

Preheating hot water circuits

Our sludge-water and air-water heat exchangers are ideally suited for preheating water circuits. This pre-heated water can be used internally. 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.

A tailor made solution for your company

Task/Läckeby from Sweden produce and install all necessary infrastructure to make your heat exchanger installation as efficient as possible. Our heat exchangers are fully customised and integrated 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 reception 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 will give you more information about the projects.