TECHNICAL ISO/TR
REPORT 20736
First edition
Sludge recovery, recycling, treatment
and disposal — Guidance on thermal
treatment of sludge
Valorisation, recyclage, traitement et élimination des boues — Lignes
directrices pour le traitement thermique des boues
PROOF/ÉPREUVE
Reference number
ISO/TR 20736:2021(E)
ISO 2021
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ISO/TR 20736:2021(E)
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© ISO 2021

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ISO/TR 20736:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................vi

Introduction ..............................................................................................................................................................................................................................vii

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Abbreviated terms .............................................................................................................................................................................................. 3

5 Sludge properties................................................................................................................................................................................................. 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Physico-chemical characteristics ............................................................................................................................................ 4

5.2.1 General...................................................................................................................................................................................... 4

5.2.2 Dry matter ............................................................................................................................................................................. 4

5.2.3 Loss on ignition ................................................................................................................................................................. 4

5.2.4 Calorific value ..................................................................................................................................................................... 5

5.2.5 Grease, scum and screening ................................................................................................................................... 5

5.2.6 Physical consistency and others ......................................................................................................................... 6

5.3 Chemical and microbiological characteristics ............................................................................................................. 6

5.3.1 General...................................................................................................................................................................................... 6

5.3.2 Sulfur .......................................................................................................................................................................................... 6

5.3.3 Phosphorus ........................................................................................................................................................................... 7

5.3.4 Nitrogen ................................................................................................................................................................................... 7

5.3.5 Chlorine and other halogens ................................................................................................................................. 7

5.3.6 Organic micro pollutants .......................................................................................................................................... 7

5.3.7 Trace elements................................................................................................................................................................... 8

5.3.8 Pathogens ............................................................................................................................................................................... 8

6 Thermal processes fundamentals ...................................................................................................................................................... 8

6.1 General ........................................................................................................................................................................................................... 8

6.2 Drying ............................................................................................................................................................................................................. 9

6.3 Hydrolysis .................................................................................................................................................................................................10

6.4 Incineration ............................................................................................................................................................................................11

6.5 Pyrolysis.....................................................................................................................................................................................................12

6.6 Gasification ..............................................................................................................................................................................................13

6.7 Thermolysis ............................................................................................................................................................................................14

6.8 Carbonization ........................................................................................................................................................................................14

6.9 Wet oxidation ........................................................................................................................................................................................14

6.10 Melting ........................................................................................................................................................................................................15

6.11 Pasteurization .......................................................................................................................................................................................15

7 Technologies ..........................................................................................................................................................................................................16

7.1 General ........................................................................................................................................................................................................16

7.2 Drying ..........................................................................................................................................................................................................16

7.2.1 Direct dryers .....................................................................................................................................................................16

7.2.2 Indirect dryers ................................................................................................................................................................20

7.2.3 Solar dryers .......................................................................................................................................................................22

7.3 Hydrolysis .................................................................................................................................................................................................23

7.4 Incineration ............................................................................................................................................................................................24

7.4.1 Fluidized bed furnace ...............................................................................................................................................24

7.4.2 Multiple hearth furnace (MHF) ........................................................................................................................28

7.4.3 Hybrid furnace ................................................................................................................................................................31

7.4.4 Others .....................................................................................................................................................................................32

7.5 Pyrolysis.....................................................................................................................................................................................................33

7.6 Gasification ..............................................................................................................................................................................................33

7.7 Thermolysis ............................................................................................................................................................................................35

7.8 Carbonization ........................................................................................................................................................................................36

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ISO/TR 20736:2021(E)

7.9 Wet oxidation ........................................................................................................................................................................................36

7.10 Melting ........................................................................................................................................................................................................37

7.11 Pasteurization .......................................................................................................................................................................................39

7.12 Emerging technologies ..................................................................................................................................................................40

7.12.1 General...................................................................................................................................................................................40

7.12.2 Oxidation technologies ............................................................................................................................................40

7.12.3 Enzymatic sludge hydrolysis ..............................................................................................................................41

7.12.4 Plasma gasification .....................................................................................................................................................41

7.12.5 Ultrasound pretreatment ......................................................................................................................................41

7.12.6 Microwave irradiation ..............................................................................................................................................41

7.12.7 Infrared radiation .......................................................................................................................................................42

7.13 Design aspects ......................................................................................................................................................................................42

7.14 Auxiliary equipment ........................................................................................................................................................................42

7.14.1 General...................................................................................................................................................................................42

7.14.2 Transport, receiving area, storage and feeding systems ............................................................43

7.14.3 Heat supply and recovery .................. ....................................................................................................................43

7.14.4 Gas cleaning ......................................................................................................................................................................44

7.14.5 Ash and other residues handling ....................................................................................................................44

7.14.6 Wastewater treatment .............................................................................................................................................44

7.14.7 Process monitoring .....................................................................................................................................................44

7.14.8 Safety systems .................................................................................................................................................................45

8 Operational aspects ........................................................................................................................................................................................45

8.1 General ........................................................................................................................................................................................................45

8.2 Drying ..........................................................................................................................................................................................................46

8.3 Hydrolysis .................................................................................................................................................................................................46

8.4 Incineration ............................................................................................................................................................................................46

8.4.1 General...................................................................................................................................................................................46

8.4.2 Fluidized bed furnace ...............................................................................................................................................47

8.4.3 Multiple hearth furnace ..........................................................................................................................................48

8.5 Pyrolysis.....................................................................................................................................................................................................49

8.6 Gasification ..............................................................................................................................................................................................49

8.7 Thermolysis ............................................................................................................................................................................................49

8.8 Carbonization ........................................................................................................................................................................................49

8.9 Wet oxidation ........................................................................................................................................................................................49

8.10 Melting ........................................................................................................................................................................................................50

8.11 Pasteurization .......................................................................................................................................................................................50

8.12 Hazards .......................................................................................................................................................................................................50

9 Management of energy and secondary resources ..........................................................................................................50

9.1 General ........................................................................................................................................................................................................50

9.2 Drying ..........................................................................................................................................................................................................51

9.3 Hydrolysis .................................................................................................................................................................................................51

9.4 Incineration ............................................................................................................................................................................................51

9.5 Pyrolysis.....................................................................................................................................................................................................52

9.6 Gasification ..............................................................................................................................................................................................53

9.7 Thermolysis ............................................................................................................................................................................................54

9.8 Carbonization ........................................................................................................................................................................................54

9.9 Wet oxidation ........................................................................................................................................................................................54

9.10 Melting ........................................................................................................................................................................................................54

9.11 Pasteurization .......................................................................................................................................................................................54

9.12 Thermal treatments and circular economy .................................................................................................................55

10 Management of residues ...........................................................................................................................................................................55

10.1 General ........................................................................................................................................................................................................55

10.2 Flue gas .......................................................................................................................................................................................................55

10.2.1 Characteristics and parameters .......................................................................................................................55

10.2.2 Equipment ..........................................................................................................................................................................57

10.3 Ashes .............................................................................................................................................................................................................59

10.3.1 Composition/parameters ......................................................................................................................................59

10.3.2 Processes and equipment .....................................................................................................................................60

10.4 Wastewater .............................................................................................................................................................................................61

11 Decommissioning of installations ...................................................................................................................................................61

11.1 General ........................................................................................................................................................................................................61

11.2 Specific considerations .................................................................................................................................................................61

12 Co-management with other organic wastes ..........................................................................................................................62

12.1 General ........................................................................................................................................................................................................62

12.2 Specific considerations .................................................................................................................................................................63

12.3 Additional storage and transport aspects ....................................................................................................................65

12.3.1 General...................................................................................................................................................................................65

12.3.2 Storage ...................................................................................................................................................................................65

12.3.3 Transport .............................................................................................................................................................................66

13 Assessment of sustainability ................................................................................................................................................................66

13.1 General ........................................................................................................................................................................................................66

13.2 Environmental aspects ..................................................................................................................................................................67

13.3 Economical aspects ..........................................................................................................................................................................67

13.4 Social aspects.........................................................................................................................................................................................67

Annex A (informative) Calorific values calculations .........................................................................................................................69

Annex B (informative) Various systems to input sludge into a household waste incineration

plant ................................................................................................................................................................................................................................70

Annex C (informative) Case studies ....................................................................................................................................................................72

Annex D (informative) Regulatory aspects .................................................................................................................................................86

Bibliography .............................................................................................................................................................................................................................89

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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

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This document was prepared by Technical Committee ISO/TC 275, Sludge recovery, recycling, treatment

and disposal.

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vi PROOF/ÉPREUVE © ISO 2021 – All rights reserved
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ISO/TR 20736:2021(E)
Introduction

Sludge treatment and management is globally a growing challenge for most countries:

— sludge is a by-product of water treatment process
...

ISO/PRF TR 20736

Sludge recovery, recycling, treatment and disposal -- Guidance on thermal treatment of sludge

Sludge recovery, recycling, treatment and disposal -- Guidance on thermal treatment of sludge

Valorisation, recyclage, traitement et élimination des boues -- Lignes directrices pour le traitement thermique des boues

General Information

Buy Standard

Standards Content (sample)

Questions, Comments and Discussion

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Sludge recovery, recycling, treatment and disposal -- Guidance on thermal treatment of sludge

Valorisation, recyclage, traitement et élimination des boues -- Lignes directrices pour le traitement thermique des boues

General Information

Buy Standard

Standards Content (sample)

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.

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