PRODUCE QUALITY SLUDGE AND GENERATE

SAVINGS WITH PRE-LIMING

BIOSOLIDS

Dehydris™Lime

ADVANCED DEWATERING OF SLUDGE BY PRE-

LIMING BEFORE CENTRIFUGATION

P-PPT-B-005-EN-1107

BIOSOLIDS

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CONTENTS

Dehydris™

Lime � Dehydris™ Lime on the dryness scale

� Dehydris™ Lime Workshop

� Uses and post treatments

� Operation Description

� The plus of Dehydris™ Lime

� References

� Case Study: Calais (62), FRANCE

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Dehydris Lime DRYNESS SCALE COMPARISON

Dehydris™

Lime

0.4 %Dryness

4 – 6 %20 – 45 %

60 – 90 %

Process Thickening Dehydration Drying

Sludge volume /

Extracted water volume

Range Name Drainis™ Dehydris™ Evaporis™

Process Name Drainis™ Turbo

Dehydris™ Osmo

Dehydris™ Lime

Dehydris™ Twist

Evaporis™ LT

Evaporis™ LE

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Dehydris Lime PROCESS (1/2)

Dehydris™

Lime

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Dehydris Lime PROCESS (2/2)

Dehydris™

Lime

6

Landfill Agriculture re-use

Dehydris Lime

• Reduced volume of cake• Calcium intake • Heap holds its shape• Biological stability

• Reduced volume of cake • Dryness: 30%

• No recycling (dryers STC, BDS)• Improved drying kinetic

Thermal Drying

Dehydris Lime – USES AND POST TREATMENTS

Post treatments

UsesUses

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Area of application:

• Physical-chemical and biological UWW sludge, whether or not digested

Used limes:

• Quicklime thermicity delayed

• Quick lime thermicity delayed or fine quick lime

• Liquid lime solution ready for use

Polymers:

• High pH stable polymers

• Standard polymer is used for digested sludge

OPERATION DESCRIPTION

Dehydris™

Lime

tem

péra

ture

time

60°°°° C

Quicklime thermicity delayed

� Maintaining the rate of reaction� Delayed activation as sharp

as for classic quicklime

Classic quicklime

Reactivitydelay

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Dehydris Lime ADVANTAGES

• Intimate mixing of lime in sludge – stability sustainable organic

• Identical dryness to that obtained with post-liming

– up to 50% gain compared to dewatering with centrifuge only

• Granular structure– heap holds its shape

• Reduced phosphate content in the centrates returned to the plant inlet

• Simple implementation• Easy-to-run unit • Enhanced security

– No mechanical blade mixer

– No dust

Dehydris™

Lime

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Contract CapacityStart-up Date

Type of sludge

Sludge-end use

Calais (62), France 120,000 PE 2007 Activated sludge Agricultural spreading

Île d’Arrault (45), France 100,000 PE 2011 BRM (Ultrafor™) Agricultural spreading

Basse Wavre, Belgique 200,000 PE 2010 Anaerobic digestion Agricultural spreading

Château-Thierry (02), France 40,000 PE 2012 Activated sludge Agricultural spreading

AMONG Dehydris Lime REFERENCES

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A CASE STUDY: CALAIS « JACQUES MONOD » (62), FRANCE

CONTEXT:

• A 120 000 p.e. UWW treatment plant (prolonged aeration)

• Replaces post-liming (mixer out of use) by pre-liming prior to centrifugation (a Degrémont Services achievement)

• Pre-liming commissioned in 2007

DESIGN:

• The sludge treatment line:– Floatation, pre-liming, centrifugation

• Treatment capacity : 800 Kg DS/hour

• Delayed temperature increase quick lime, lime treatment rate: 30% CaO/DS

• Centrate dephosphatation efficiency >75%

• Final dry solids content: 28%

• Sludge end use:agricultural spreading