900
Influent BOD7 load kg/day
800
700
600
500
FWD installation started
Surahammar influent BOD load
400
300
200
100
0
Biochemical oxygen demand a big part of treatment load
300
Influent N load kg/day
250
200
FWD installation started
Surahammar influent nitrogen load
150
100
50
0
Total nitrogen another part of treatment load
Surahammar biogas
600
500
450
y = 12.456x - 24519
R² = 0.6996
FWD installation
started
Average annual biogas m3 /day
550
400
350
300
1995
1997
1999
2001
2003
2005
2007
2009
Surahammar influent
monitoring data
Compares 0% FWD with 50% FWD
Flow m3/d kgBOD7/d
Mean pre FWD
120 weeks 11/01/95-30/04/97
Variance
Mean post FWD
120 weeks 13/12/06-01/04/09
Variance
Difference
(post120-pre)
P (1-tail T-test)
kgCOD/d
BOD7:N m3 biogas/d
kgN/d
kgNH4/d
kgP/d
74.0
18.0
3.50
331
4706
408
1084 113.6
3034123
46620
394192
979
405
49.9
1.695
1036
4678
331
892
107
71
13.3
3.11
484
5675190
17138
167426
548
282
12.7
1.191
3147
-0.59%
-19.0%
-17.7%
-6.1%
-3.9%
-26.1%
-11.1%
+46%
0.50
0.06
0.09
0.18
0.28
0.002
0.11
0.01
Sewers
Sewer “dry” biofilm
Sewer atmosphere
“intertidal” biofilm
Both conveyance
system and
ecosystem
treatment starts in
sewers
Bulk water/wastewater
Sewer “wet” biofilm
Aerobic e.g.
Nitrosomonas
NH4+ → NO2- + H+
Anaerobic e.g. anammox
NO2- + NH4+ → N2
6
FOG (fat oil and grease)
•
•
Great biogas potential
Saponification in sewer
converts to blockage
– elevated pH implicated;
– strength related to calcium;
– forms 100-200m downstream of FSE;
– No evidence of FWD output in FOG samples around USA
Northumbrian Water
world class AD
•
•
Teesside and Tyneside
4.7 MW electricity each
– Renewable baseload
•
100% of NW sludge treated by Cambi AD
•
Biosolids recycled to agriculture
– Completing nutrient cycles and conserving soil
organic matter
•
Reduces NW’s CO2e by 50,000 t/year
Sewage sludge
The use of Sewage sludge on land according to the Sludge
(use in agriculture) Regulations
•
Extensive scientific literature
– Concentrations
– Fate and transport
– Agronomy
•
Sophisticated controls and monitoring system
•
>35 years’ operational experience
•
Hazardous substances legislation has banned the most
dangerous
Metals
Dioxins and furans
Conclusions
•
“one size” will not fit all;
– home composting fits some, kerbside collection fits others and FWD fit others,
especially (but not exclusively) people in flatted properties.
•
Exclusive emphasis on kerbside collection of source segregated biowaste has been
mistaken.
•
FWD do not stress infrastructure or increase water company costs
•
•
AD, biogas, CHP and electricity export at WwTW are well established
Use of biosolids to conserve soil organic matter and complete nutrient cycles is ‘safe’
•
The evidence all shows use of FWD is a good option
CIWEM P.P.S. February 2011
“One size most definitely does not fit all……exclusive emphasis on segregating
and collecting biodegradable waste from households has been a mistake.”
CIWEM 18 Feb. 2011
•
Policies and strategies should be evidence based.
•
Diversity of options for the disposal of food make
recycling valuable waste easier .
•
FWDs could provide an opportunity for cost saving to
society as a whole.
www.ciwem.org/policy-and-international/policy-position-statements/food-waste-disposers.aspx
Next steps?
We would like to work with each of you:
• Understand your challenges
• Increase your knowledge of our technology
• Secure your endorsement
Some of our ideas are:
• Briefings like this one
• Study tours
• Pilot projects
We’d like to hear yours ............
More information: www.food-waste-disposer.org.uk
References
Nilsson, P.; Lilja, G.; Hallin, P.-O.; Petersson, B. A.; Johansson, J.; Pettersson, J.; Karlen, L. (1990) Waste
management at the source utilizing food waste disposers in the home; a case study in the town of Staffanstorp.
Dept. Environmental Engineering, University of Lund.
Diggelmann, Carol and Ham, Robert K. (1998) “Life-Cycle Comparison of Five Engineered Systems for
Managing Food Waste.” Department of Civil and Environmental Engineering, University of Wisconsin. January
1998.
Kegebein, Jörg; Hoffmann, Erhard; and Hahn, Herman H. (2001) Co-Transport and Co-Reuse. An Alternative to
Separate Bio-Waste Collection? Wasser-Abwasser GWF 142 (2001) Nr. 6 429-434
Parfitt, J. (2002) Analysis of household waste composition and factors driving waste increases. WRAP
Report on Social Experiment of Garbage Grinder Introduction. Technical note of National Institute for Land and
Infrastructure Management, Japan. No. 226 March 2005
Evans, T.D. (2007) Environmental Impact Study of Food Waste Disposers: a report for The County Surveyors’
Society & Herefordshire Council and Worcestershire County Council, published by Worcestershire County
Council.
Battistoni, P.; Fatone, F.; Passacantando, D.; Bolzonella, D. (2007) Application of food waste disposers and
alternate cycles process in small-decentralized towns: A case study. Water Research 41 893 – 903
Evans, T.D.: Andersson, P.: Wievegg, A.: Carlsson, I. (2010) Surahammar – a case study of the impacts of
installing food waste disposers in fifty percent of households. Water Environ. J. 24:309-319
CIWEM (2010) Wastewater Biosolids - Treatment and Use - policy position statement. Chartered Institute of
Water and Environmental Management
CIWEM (2011) Food waste disposers – policy position statement.
CIWEM (2012) Phosphorus: wastewater's role in stewardship of a vital resource - policy position statement.
Evans, T. D. (2012) Domestic food waste, the options compared (particularly food waste disposers) and their
carbon and financial costs. Municipal Engineer 165 3-10
Available from:
http://www.food-waste-disposer.org.uk/the-science
www.timevansenvironment.com
http://www.ciwem.org/policy-and-international/policy-position-statements.aspx