COMPARATIVE STUDY OF THE METHODS USED FOR THE TREATMENT AND FINAL DISPOSAL OF SEWAGE SLUDGE IN EUROPEAN COUNTRIES ALEXANDROS KELESSIDIS1, ATHANASIOS S. STASINAKIS1,2 1School
of Science and Technology, Greek Open University, Patra, Greece 1,2Water and Air Quality Laboratory, Department of Environment, University of the Aegean, University Hill, 81100 Mytilene, Greece Email:
[email protected]
INTRODUCTION Facts 11.519 t DS/y total sludge production in EU. Old member-states (EU-15): 37% increase of sewer sludge production in the period 1992-2005. New member-states (EU-12): 100% increase in sludge production is expected.
Sludge treatment and disposal in EU is an issue:
Legal constraints
+
Relative legislation remains fragmentary and quite old (Directive 86/278/EEC). Directive 99/31/EC and Decision 2003/33/EC practically prohibit sludge landfilling.
Aims of the study ‘Unify’ existed reports and relative literature that usually contain incomplete, inhomogeneous and sometimes contrary elements. Outline current situation. Discuss future perspectives.
Open Urgent Complicated
Forced mainly by Implementation of Directive 91/271/EEC
MATERIALS AND METHODS
RESULTS AND DISCUSSION
Sources of data used for
Table 1. Sludge treatment methods reported by EU Member States (Ref. [3], [4] ) Stabilisation
Disposal Method Used (%)
80
2 6
6
6
5
4
33
21
15 18
60 11
Sludge disposal evolution in EU-15 (Fig. 1)
18
29
Others
13
Surface waters Landfill Incineration
40
Reuse
57 48
54
50
47
Centrifuges
Belt filter press
Thermal drying
X XX X X X X XX X
Drying beds
X X X
X
X
X
X XX
X
X
X
X
X X X X XX X X x
Thermal
X
X
Polymers
X
Other inorganics (NH3, Iron salts, etc)
X x
Lime
x X
X X X
X X X
x
x X x X X X X X
X
X XX X x x x X X X
XX X XX
X X X
x X X
Bulgaria X Χ Cyprus Χ Χ Czech Republic XX Χ Estonia Hungary X Latvia X Lithuania X Malta Poland XX X Romania Slovakia X XX Slovenia X x x Rare method
Χ
x x XX XX XX x X
X
X
X
X
X
X X X
X X X
X
X
X
X
XX X
X X
X X X X
X X
X X
X X
X
X
X
X X X
New Countries
15
18
X X
Dewatering Filter Press
Austria Belgium (Flanders) Belgium (Wallonia) Denmark Finland France Germany Greece Ireland Italy Luxembourg Netherlands Portugal Spain Sweden UK
Last available Eurostat data (2009). Very last report by Milieu Ltd, WRc and Risk & Policy Analysts Ltd (RPA) (2010). References from individual countries.
9
14
X X
Significant differences between: Member States (e.g Spain and Czech Republic). Regions of the same country (e.g. Flanders and Wallonia in Belgium). Digestion –aerobic, anaerobic is the most common stabilisation method. Composting and lime stabilisation are used considerably in a few countries (e.g. Finland, Poland). Mechanical dewatering is preferred instead of drying beds. Thermal drying is favorable technology in EU-15 countries (e.g Germany, Flanders), instead of scarce use in EU12 (only Slovenia).
EU-15
Figure 1. Chance of final disposal methods in EU-15 (Eurostat, Ref. [1] – [3]) 100
Composting
2. Discuss current trends and future perspectives:
Lime
European Commission’s (EC’s) reports for the implementation of Directives 91/271/EEC and 86/278/EEC, for the period 1992 - 2006. EC’s review study in 2001. Eurostat data. European Environmental Agency’s (EEA’s) reports. Relative literature.
Anaerobic
Country
Conditioning
Aerobic
1. Outline past and current situation:
Sludge Treatment in EU
Landfilling has over sub-doubled in 13 years, decreasing from 33 to 15%. Sludge incineration has almost doubled, from 11 to 21%. Biosolids reuse (= agriculture utilization + composting) has a quite significant increase (12,5%)
X X
Χ Χ
x X XX x X
x
X X
Common use
Χ
X
X
X
X
XX
CONCLUSIONS
X x X X Most common use
XX
Figure 3. Descending sorting of EU-27 Member States in “green” line (Eurostat most recent year, Ref [2], [4])
20
28% Agricultural use
Compost
Incineration
Landfill
Malta (2009)
Greece (2008)
Slovenia (2009)
Belgium (2008)
Romania (2009)
Incineration
Poland (2009)
Agricultural use
Others
Bulgaria (2009)
Compost
Austria (2008)
Compost
Lithuania (2007)
Landfill
Italy (2005)
Landfill
Germany (2008)
35%
Latvia (2007)
21%
Sweden (2009)
0% Others
Netherlands (2006)
21%
10% Denmark (2007)
15%
Incineration
1%
20%
Hungary (2007)
44%
Agricultural use
30%
Spain (2006)
16%
40%
Slovakia (2007)
9% 10%
50%
Ireland (2007)
Sludge management in EU-12
60%
UK (2005)
Sludge management in EU-15
70%
France (2008)
Figure 2. Methods of sludge final disposal in 2005 (Eurostat 2005 or next year, Ref. [1] – [4])
80%
Estonia (2009)
Year
90%
Czech Republic (2008)
2005
Portugal (2007)
2000
Cyprus (2007)
1998
Luxembourg (2008)
1995
Finland (2005)
1992
Sludge Disposal Methods (%)
100%
0
Others
“Old” and “new” Member States’: Different philosophy (Fig. 2) Recycling in agriculture is the prevailing technology in EU-15 (44%), while landfilling is preferred in EU-12. Incineration is the second preferable choice in EU-15 (21%), but it scarcely applied in EU-12 (1%). Composting is more spreaded in EU-12 (21%) compared to EU-15 (10%)
Abandoning landfilling, EU countries have to choose between agriculture use and incineration. The preferable route is going to arise from the particular conditions in each individual country. Biosolids reuse on land is expected to reach an overall percentage of 50% around 2020. By 2020, penetration of incineration is possible to reach 37% in EU-15, overdoubled compared to EU-12.
Great variations among Member States (Fig. 3) The “greener” EU country is Finland with nearly 100% biosolids reuse. The worse ecologic position is occupied by Malta (100% landfilling). Netherlands presents the great preference in incineration (68%).
REFERENCES [1]. EC (2004), Report on the implementation of Council Directive 91/271/EC. [2]. EC (2006), Report on the implementation of Directive 86/278/EEC. [3]. EEA (2002), Review of selected waste streams: Sewage sludge etc. [4]. Milieu Ltd, WRc and RPA (2010), Environmental, economic and social impacts of the use of sewage sludge on land.
