Sludge dewatering

With sludge dewatering, the HILLER DecaPress among the entire field of competition is characterised by being particularly easy to set up and runs very robustly and stably during everyday use. And all this with high throughput levels and considerably reduced consumption of power and flocculant. In the discharge, Hiller decanters achieve maximum dry solids content, which in turn result in reduced disposal costs. The development of the new DecaPress sees HILLER continuing down this path. In addition to countless improvements in detail, the new HILLER DecaPress features a revolutionary drive concept: the HILLER SEE Drive.

Sludge thickening

For sludge thickening, a decanter is used that has been designed specifically for this task. In most cases, this is carried out without flocculant and achieves maximum recovery figures. The excessive sludge is concentrated to a certain dry substance (ds) content, which was defined beforehand. This special Hiller decanter technique reduces the sludge volume by up to 90 percent.

Everything from one source – the complete Hiller concept

As well as manufacturing decanters, Hiller is available to customers for the design and selection of the optimal system components. Hiller gladly undertakes the planning and implementation of the entire system.

Contact us for sludge analyses made in our modern laboratory in Vilsbiburg

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Schematic diagram with a HILLER DecaPress centrifuge for dewatering of sewage sludge

Hiller DecaPress decanter at WWTP Grünstadt (Germany)

SEWAGE SLUDGE DISINTEGRATION BY CENTRIFUGE

Advantage based on experience - HILLER delivers new, expert practical data

Rising sludge disposal costs mean continual pressure to optimise sludge treatment at sewage treatment plants. The approach of using a disintegration process to generate technical and economic advantages for further sludge treatment is not a new one. A wide range of physical and chemical solutions all aim to achieve the following overall goals:

• Reduced viscosity and better pumping properties
• Increased degradation of the organic part (i.e. extended dwell time in the digestion tank)
• Increase in gas yield
• Improved drainage behaviour

HILLER GmbH can demonstrate a specific advantage in this field of application as a manufacturer of high-performance centrifuges.

Hiller DP45N without lysing device

DP45N with lysing device

DP45N with lysing device

Basic procedural approach:
Waste activated sludge (WAS) is generally mechanically thickened prior to mixing with the primary sludge, in order to achieve an optimal consistency in the raw/mixed sludge subsequently before digestion. The amount of sludge added to the digestion tank is therefore reduced by means of a waste activated sludge thickening process. This provides energy savings and better digestion tank utilisation and/or longer detention times in the digestion stage. This results in reduced amounts of digested sludge and improved dewatering properties of the digested sludge.

HILLER centrifuges can be operated with an additionally installed lysing device.
This lysing device is attached in the area of the sludge discharge openings and uses the existing kinetic bowl energy. This means that the additional power consumption of 0.02 to 0.05 kW/kgTR can also be kept correspondingly low.

The disintegration effects in the thickened waste activated sludge (WAS) essentially take place by impact and shear forces generated by rotating knife blades in the labyrinth and the lysing chamber at high circumferential velocity. The WAS disintegration is completed in the full flow of the thick sludge entering the lysing device, meaning that only the WAS thick sludge thickened in the centrifuge is lysed and no lysate enters the separated centrate water.

Mechanical construction:
The lysing device consists of a labyrinth with a lysis chamber fitted with window openings. Fork blades fitted onto the centrifuge bowl rotate through the lysis chamber, and these blades are protected against wear with tungsten carbide plating. From the discharge openings of the centrifuge, thickened waste activated sludge thrown out at high speed flows through the lysis chamber in the axial direction.

Other than the lysing device, no additional plant technology is required.

Equipping a HILLER thickening centrifuge with a lysing device therefore combines the following processes:

• WAS thickening
• WAS disintegration
• WAS liquefaction (change in viscosity of the thickened WAS)

 
For more information on our lysat technology, please see our flyer on thickening and disintegration and the lysat technology.