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Decanter vs. Screw Press

Decanter vs. Screw Press

Decanter vs. Screw Press

Product catalog summary
Introduction
This document compares decanter centrifuges and screw presses for solid/liquid separation in wastewater treatment, highlighting the advantages of decanter centrifuges.

Specifications and Performance
Decanter centrifuges achieve a dry substance (DS) content improvement of +5% with a solids capture efficiency of ≥ 99%. This performance is consistently proven with HILLER high-performance decanter centrifuges.

Cost Efficiency
Operators of municipal wastewater treatment plants often face high sewage sludge disposal costs due to suboptimal dewatering technology. Decanter centrifuges offer significant savings potential compared to competitor technologies, reducing disposal costs.

Separation Efficiency
Decanter centrifuges provide superior separation efficiency, achieving stable results over 99%, eliminating the need for centrate water aftertreatment. In contrast, screw presses achieve only 90-95% efficiency, requiring complex and costly post-treatment.

Mobile Test Plants
Decanter centrifuges are available in all sizes for mobile testing, whereas screw presses are limited to nominal throughputs of less than 30m³/h, often leading to discrepancies in scale-up calculations.

Optimization and Economic Efficiency
Decanter centrifuges are well adjustable to changing mud characteristics and offer clear economic advantages in large-scale technology comparisons. Screw presses have limited intervention possibilities and do not match the economic efficiency of centrifuges.

Maintenance and Power Consumption
Decanter centrifuges require higher power consumption and maintenance costs, but these are considered subordinate factors in overall cost comparison. Screw presses have lower power consumption and maintenance costs but require manual cleaning.

Conclusion
The document concludes that decanter centrifuges offer clear advantages in dewatering performance, separation efficiency, and economic benefits, making them the preferred choice for modern wastewater treatment plants.
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Catalog excerpts

Decanter vs. Screw Press-1

DECANTER CENTRIFUGES & PLANTS FOR SOLID/LIQUID SEPARATION DECANTER VS. SCREW PRESS A COMPETITION WITH A CLEAR WINNER Dry substance content in the sludge: Improvement of +5% DS (absolute) with a solids capture efficiency of ≥ 99% are repeatedly achieved and proven with HILLER high performance decanter centrifuges. Many operators of municipal wastewater treatment plants are faced with unnecessarily high sewage sludge disposal costs due to the dewatering technology applied. However, the dewatering result can almost always be optimized and the disposal costs thus be reduced. A large number of tests with our mobile plants show a considerable savings potential through the use of decanters in comparison with competitor technologies. These practical experiences from the direct comparison tests show clear advantages for the centrifuge technology not only in the area of throughput and dewatering performance but also in the separation result of the liquid phase. Separation efficiencies of only 90 to 95% lead to correspondingly high back-loading values for the wastewater treatment plant, which have the effect of a continuous accumulation of fine particles in the wastewater treatment plant system. For this reason, operators decide in favour of modern decanter technology after a well-founded technology comparison on their own plant. A comparison that we can recommend and offer before making such a long-term decision. With very manageable effort, you can quickly see the amount of operating cost savings that can be achieved, and a high degree of separation also provides procedural advantages for your entire wastewater treatment. separation & process

 Open the catalog to page 1
Decanter vs. Screw Press-2

DIRECT COMPARISON SCREW PRESS DEWATERING RESULT (Largest economic factor influencing annual operating costs) SEPARATING EFFICIENCY MOBILE TEST PLANTS OPTIMISATION FRIENDLINESS ECONOMIC EFFICIENCY POWER CONSUMPTION Up to 5% DS (absolute) better dewatering result Stable >99% No centrate water aftertreatment required Clear disadvantages, especially for sludge with „difficult“ dewatering properties, e.g. winter sludge On a daily average, taking into account the regular screen cleaning cycles, only 90 - 95%, resulting in considerable backloading with fines. Necessary post-treatment of the centrate...

 Open the catalog to page 2
*Prices are pre-tax. They exclude delivery charges and customs duties and do not include additional charges for installation or activation options. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates.