GIOTTO WATER has technologies to best meet all drying requirements!

Thermal drying is a process for the reduction of the volume of wet solid products, by removing the water and achieving dry solids concentration over 90% DS. This process has proven applications in both the environmental field (volume reduction of sludge from wastewater treatment plants) as well as in production processes of industries, such as chemical, pharmaceutical, food processing and minerals processing. In thermal drying process, the final product is stabilized in a dry granular form that simplifies the storage, delivery, use or disposal.


Thermal drying of sludge allows to obtain a final product suitable for reuse in different applications depending on the composition of the treated product.


  • Municipal wastewater treatment
  • MSW Anaerobic digestion
  • Distilleries
  • Breweries
  • Slaughterhouses
  • Farms
  • Tanneries
  • Oil mills
  • Textile industries
  • Chemical/pharmaceutical

Other products:

  • Food industries (soybeans, yeasts, starches, etc.)
  • Pharmaceutical industry (mycelia, pectines, etc.)
  • Chemical industry (hydroxides, acrylic, emulsions, polypropylene, PVC, etc.)
  • Mining industry (coal, iron and copper, dust, carbonates, calcium sulphate, etc.)

Regardless of the design requirements (type of product to be dried, available energy, evaporation capacity, etc.), Giotto Water is able to offer the technological solution most suitable for every problem, adapting the project to the Customer needs.

  • CTD – Convective Thermal Dryer
  • ECOFLASH – Thin Layer Dryer
  • SBD – Sludge Belt Dryer

CTD – Convective Thermal “triple pass” drum dryer

The wet product is dried by a stream of hot air. The process is performed inside an enclosed rotating drum.

Water evaporation capacity ranges from 1.000 to 10.000 kg/h The drying air stream is heated by a heat generator.

The process is performed inside an enclosed rotating drum consisting of three coaxial cylinders.

There are no rotating parts inside the drum with no wearing problems.

The dried product has a homogeneous and granular shape and is recovered in the product/process air separation section.

Different plant configurations are available according to the specific project conditions:

  • Total recycling of the process air, heated in an air/air heat exchanger arranged in series with the heat generator
  • Heat recovery from cogeneration plants or other waste heat sources
  • Reduction of washing and condensation water needs, through recirculation and cooling with evaporative towers
  • Exhaust gas deodorization by thermal, biological or chemical treatment


ECOFLASH – Thin Layer Dryer

A high speed rotor centrifuges the product on the internal hot wall of a stator, heated with diathermic oil or steam, which transfers the heat to the “thin layer” of sludge.

Water evaporation capacity ranges from 750 kg/h to 3.000 kg/h.

The product to be treated is introduced into a drying chamber, constituted by a jacketed stator heated with diathermic oil or steam.

Inside the stator, a cylindrical coaxial rotor with adjustable paddles operates at a peripherical speed of 30 m/s.

The product is centrifuged on the stator in a thin layer with a thickness of 5 mm, in contact with the hot wall.

The paddles mix and extract the dried product, while an air flow, in countercurrent, allows the extraction of water evaporated and cools the dried sludge simultaneously.

The limited amount of air has the only purpose of transporting the water evaporated during the drying process, while all necessary heat is provided by conduction through the wall of the stator.

The drying process is single passage, continuous without recycle.

The dried product is granular, and dust free.

The main advantages of this technology are:

  • Application with different types of inlet product (organic and inorganic)
  • Reduced energy consumption
  • Minimum air flowrate and low emissions
  • Minimum plant footprint


SBD – Sludge Belt Dryer

Able to work with different energy sources and particularly suited to the reuse of waste heat at low temperature. It has extreme operational flexibility, also with products to be treated at variable characteristics, thanks to the possibility to adjust the belt speed and the process temperatures.

Water evaporation capacity ranges from 250 to 6.000 kg/h. The belt dryer is a convective dryer, where the water is evaporated by a stream of heated air, that goes in contact with the wet product during its transport on a belt.

The dryer is configured with two drying belts, which allow to obtain the correct contact time between sludge and hot air, making it extremely flexible in terms of flowrate and final dryness achievable.

An inlet distribution system is necessary to preform the dewatered sludge and distribute evenly over the width of the upper belt for further transport within the drying tunnel, where a ventilation system allows to distribute the heated air on the sludge in a uniform and constant manner.

The main advantages of this technology are:

  • Application with different types of inlet product (organic and inorganic)
  • Pelletized final product with no dust
  • Reduced energy consumption and the possibility of recovering heat from sources at low temperature
  • Low emissions
  • Low process temperature
  • Easy installation and reduced footprint
  • Modular construction