sludge handling in small and mid-size treatment plants ... - sludge... · sludge handling in small...

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Workshop on Sustainable Sludge Handling / Lübeck 07.09.2011

- Introduction

Sludge handling in small and mid-size treatment plants

Dr.-Ing. Jörn Einfeldt(Privatinstitut für Klärtechnik GmbH, D-23611 Bad Schwartau, Germany)

- Case Examples: Small Treatment Plants

(i.e. WWTPs Badendorf, Gudow)

- Case Examples: Mid-size Treatment Plants

(i.e. WWTPs Ratzeburg, Ratekau)

- Summary

Page 2

German Experts on Water Management


• Consulting

• Field investigationsand data collection

• Process design and

development

• Facilities start up

• Expert‘s report

• Optimization

• Support

Introduction

Associated Partner of

Biotests and chemical

investigations

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Introduction

Schleswig-

Holstein

© GKSS, 2010

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Introduction

Reference:

Studie „Ermittlung und Bewertung der technischen

und logistischen Rahmenbedingungen bei der zukünftigen Klärschlammentsorgung in Schleswig-

Holstein“, LANU 2005

WWTPs > 100,000 PE

2

Page 5



Introduction

Reference:

Studie „Ermittlung und Bewertung der technischen

und logistischen Rahmenbedingungen bei der zukünftigen Klärschlammentsorgung in Schleswig-

Holstein“, LANU 2005

796WWTP < 100.000 PE

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Percentage of sewagesludge volumes by sizeclass

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Introduction

Biological Treatment,i.e. aeration tank Clarifier

Inlet Effluent

Return sludge

Excesssludge

Not talking about…

WWTP Carrapateira / Portugal

…constructedwetlands

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Introduction

Dumpsite Agriculturaluse

Landscape building,

composting

Incineration

In Germany:

Reference: Umweltbundesamt, Zusammenstellung aus Daten des Statistischen Bundesamtes (Stand 2009)

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Introduction

Dumpsite Agriculturaluse

Landscape building,

composting

Incineration

Schleswig-Holstein:71,5 % (2009)

Reference: Umweltbundesamt, Zusammenstellung aus Daten des Statistischen Bundesamtes (Stand 2009)

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Introduction

Required degrees of stabilisation assigned to utilisation or disposal objectives(ATV-DVWK-M-368E)

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Introduction

Recommended areas of application for biological sewage sludge stabilisation process

(Reference: ATV-DVWK-M-368E)

„ small “

„ mid-size “

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Introduction

Reference:

Disposal costs in € / m³

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Introduction

€/tDS

€/toS

Reference:DWA-Arbeitsbericht

Arbeitsgruppe AK-13.4,

KA 2010 (57) No.3

Agriculture4%DS 25%DS

0

100

200

300

400

20

40

60

80

100

Disposal costs in € / tDS, incl. transport

4

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Introduction

Drying beds(WWTP As-Salt / Jordan)

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Introduction

primary sludge surplus sludge (if necessary aerob stab.)

sludge stabilisation (digestion)

specialsolutions forpretreatment

mechanical sludgedewatering (raw sludge)

mechanical sludge dewatering

composting, conditioningfraction drying

> 40% dsdrying

>80% ds

co-incinerationcoal/ waste

mono incineration

cement industry,gasification,Low-T-Conversion

agriculture/ landscaping

thermal recycling thermal/ material recycling material recycling

(or sedimentation)

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ZV Grevesmühlen

Badendorf

Gudow

Examples small WWTPs

Neversdorf

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1) Example WWTP Badendorf (1,000 PE)

ThickenerAeration Tank

Clarifier

Leachate

Humification bed,

3 sections

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primary sludge surplus sludge (if necessary aerob stab.)





dewatering /drying / composting

fraction drying> 40% ds

drying>80% ds


mono incineration


> 12 aAgriculture /landscaping


(sedimentation / gravity thickening)

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1) Example WWTP Badendorf (1,000 PE)

Reed bed with drainage system

Dewatered sludge, 14 days after feeding

Characteristics:

- > 0.6 m²/PE- further degradation of organic material - 35 – 50% dry solids

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2) Example WWTP Gudow (4,500 PE)

Aeration Tank

Clarifier

2 Sludge ponds

old part

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3) Example WWTP Neversdorf (8,200 PE)

Aeration Tank 1(new)

2 Clarifier

2 Sludge ponds

Aeration Tank 2+3

(old)

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Page 21



primary sludge surplus sludge (aerob partly stabilized)





storing,stabilisationfraction drying

> 40% dsdrying

>80% ds


mono incineration


0,5 / 1 aagriculture


(sedimentation / thickening)

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3) Examples WWTP Neversdorf / Gudow

Sludge removal and transport

Stirrer

Sludgepump

Collection

ContainerTransport

Leachate

sewer

(closed)

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Characteristics:- 8 – 12% dry solids

(for pumping)

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Examples small WWTP


Damaged leachate sewer,caused by ice layer in winter

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4) Example Zweckverband Grevesmühlen

„Zweckverband“:Association of several communities,in this case for the purpose ofwastewater treatment

Reference: www.zweckverband-gvm.de

Centralized sludge handlingfor 31 WWTPs with a sizefrom 35 to 40,000 PE

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4) Example Zweckverband Grevesmühlen

Central WWTP Grevesmühlen:- 40,000 PE- Sludge handling for

80,000 – 100,000 PE

Reference: www.zweckverband-gvm.de

WWTP Grevesmühlen: digester, dewateringOther WWTPs: thickening, 5 %DS, transport

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Remarks on sludge thickening for small WWTPs

- Static thickening, if costs for sludge transport are low

Specific annual

costs, €/MgDS

(includingoperating costs

for digestion!)

Output DS [%DS]

Flotation

Mechanicalthickening

Static

thickening

(Reference:DWA-M-381)

- Centrifuge- Belt thickener- Drum thickener- Screw thickener

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Remarks on sludge dewatering for small WWTPs

- Dewatering (belt filter press, centrifuge, chamber filter press) or

Drying (?, different technologies…) for long transport distancesmobile or stationary units? - cooperations?

- Alternative: Drainbags (< 3,000 PE) ?

Reference: KA Betriebs-Info 2011 (41) Nr. 3oder www.panholzer-draintec.de

- Step 1: Filling

- Step 2: Dripping / Draining(30 – 35 %DS)

- Step 3: Drying,up to 80 %DS

(depending on weather conditions)

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Page 29



Ratekau

Ratzeburg

Examples mid-size WWTPs

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WWTP Ratekau, 50.000 PE WWTP Ratzeburg, 25.000 PE

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Recommended areas of application for biological sewage sludge stabilisation process

(ATV-DVWK-M-368E)

Page 32




primary sludge surplus sludge






> 40% dsdrying

>80% ds


mono incineration

cement industry,gasification,Low-T-conversion



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Page 33




5) Example WWTP Ratzeburg (25,000 PE)

Digester

Biogastank

Combinedheat and power unit

Sludgedewatering

Storage

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5) Example WWTP Ratzeburg (25.000 PE)

Digester

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Combined heat and power unit

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Sludge dewatering

(belt filter press)

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Page 37





Storage area

Dosing of lime:nutrient enrichment

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6) Example WWTP Ratekau (50,000 PE)

Inflow from Ratekau, Sereetz, Hemmelsdorf

Inflow fromWWTP Timmendorf,

including excess sludge

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primary sludge surplus sludge





> 40% dsdrying

>80% ds


mono incineration(transport)




Chem.-therm. Desintegration

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6) Example WWTP Ratekau: Flowscheme sludge

Mechanicalthickening

Excess sludgestorage

Chemical-

thermal

desintegration

2 digesters

Chamber filterpress

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6) Example WWTP Ratekau: CTD

Hot watersupply

Excess sludge

Mixer

Sodiumhydroxidesolution

Desintegratedsludge -> digester

Results:

- Higher gasproduction(but not scientifically

quantified)

- Better operating conditions(in activated sludge tank,no more bulking sludge)

© Copyright PONDUS Verfahrenstechnik GmbH, Teltow

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6) Example WWTP Ratekau: CTD

Filter belt in the

background

CTD Reactor

NaOH Dosing

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Summary

- Many different solutions for sludgehandling of small and mid-sizeWWTPs exist and are well-proven

- Different framework conditionsrequire matched process designs

- New technologies may produce newoperating challenges

- Some WWTP operators have to change the process of sludgehandling with changing legislativein Germany

Page 44



Thank you for

your attention !

Page 44Page 44Workshop on Sustainable Sludge Handling / Lübeck 07.09.2011

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