Sludge Thickening and Dewatering


Applicable to primary, secondary and tertiary sludge applications, Johnson Screens sludge treatment products play a key role in the following processes:

  • Thickening by concentration solids
  • Screening for removal of troubling solids
  • Disinfection for inactivation of pathogens
  • Dewatering by mechanical water removal
  • Incineration by thermal oxidation of organic solids

Johnson Screens offers highly efficient and comprehensive solutions for sludge treatment, from thickening to reuse.

Package Dewatering Bag Units


Technofanghi is a company located in Italy and specializes in high quality sludge treatment and dewatering systems specifically designed for small to medium size treatment plants. With their Teknobag® system, Teknofangi have adapted the well known “Geobag dewatering process” into a low-cost, continuous sludge treatment process. The system is based on a coagulation, flocculation and gravity thickening process and is fully controlled by a programmable electronic panel, ensuring optimal process operation.

The system uses an integrated coagulation, flocculation and gravity thickening and dewatering process combined in the one unit. Dry solids content of up to 30% can be achieved, depending on the nature and solids content of the sludge to be dewatered.

The Teknobag system is best adapted for treatment plants for which a larger, expensive and more maintenance intensive sludge treatment system is not suitable. The Teknobag system is the ideal addition to package plants or treatment plants in remote locations as it only requires operator attendance approximately every 3 to 4 weeks.

In production over 25 years and with over 12,000 units sold the Teknobag Draimad is an extremely well proven solution to sludge dewatering.

NZ reference available.

Sludgless Thickener

Sludge Thickener

Johnson Screens® Sludgless Thickener provides an economic solution for either sludge thickening or dewatering at small to medium size water, wastewater and industrial effluent treatment plants.

The Sludgless Thickener comprises of static circular drums with a internal screw conveyor. The drums are fabricated in stainless steel using various size Vee-Wire® screen profiles.

A screw, slowly rotating with variable speed, conveys the sludge gently upward through the inclined basket. Water drains through the basket. The degree of thickening is adjustable by means of a height adjustable weir plate in the sludge discharge and the variable screw speed. Screen cleaning is performed during screw operation by means of an automatic washing system.

Flow Capacities

1 - 10 m³/hr depending upon whether dewatering or thickening

Belt Press


A significant amount of R&D has resulted in the compact MONOBELT® – an entirely new patented belt filter press designed to combine thickening and dewatering into one single process. Sized for small and medium size treatment plants, the MONOBELT® system offers cost advantages among other benefits for municipal and industrial
end users.

The MONOBELT® uses an endless belt with spliced joint and no zippers or clips. The second belt of the machine is a filter cloth fixed on a large perforated cylinder. This has the advantage of greatly reducing the traction stresses on the filter cloth, consequently significantly increasing the product life to as much as eight times that of similar systems. The lifetime of an endless belt is about 3 – 4 times longer than a joined one.

Models available up to 30m³/hr. There are currently more than 1,100 units installed in municipal and industrial sewage treatment plants throughout Europe and the world.

Drum Thickener

The Johnson Screens rotary sludge thickener (RST) is based on the proven Milliscreen™ rotary drum screen design. This compact unit is capable of thickening primary, waste and activated or digested sludge, and delivers savings of reduced transportation and operation costs. The RST drum is constructed out of fine Vee-Wire® or wire mesh depending on the application. The system is comprised of a flocculation tank with a mixer, flow distribution tray, the RST and controls. All wetted parts and support structure are constructed of either 304 or 316 stainless steel.

The drum and mixer speed can be adjusted for maximum performance with minimal polymer use. Sludge can typically be thickened to 5 to 7 percent total solids, and in some cases up to 12 percent total solids with capture efficiencies up to 98 percent. Flows up to 90 m³/hr



Teknofanghi’s long experience in the field of sludge dewatering has led to the development of a complete range of polyelectrolyte preparation and dosing units.

The range includes the CMP semi-automatic series (since 1983) and the fully automatic CAP series (since 1994). With over 6,000 units sold Teknofanghi polydilution equipment is long proven.

The simpler CMP series is most suitable for use in small plants where the flocculant requirement is not continuous and where personnel are available for chemical make-up.

The CAP series was developed for applications in which the polyelectrolyte must be fed on a continuous basis with accurate control of dilution and ageing. This series is for polyelectrolyte on both powder and emulsion base.