Ver1.4
Farm Biobed Systems to limit point source pollution
from pesticide handling and
washdown areas.
Background Research
Summary
Developed for the Crop Protection Association and Agricultural Industries
Confederation by ADAS. The assistance of the Environment Agency, SEPA &
the Farming Unions is also acknowledged. This is part of the voluntary initiative
to minimise the environmental impact of pesticides
2
Pesticides in water:
sources of contamination
Diffuse
Point Source
Non-crop use
drift
tank filling
roads
drainflow
waste disposal
pavements
surface flow
washings
railways
interflow/base
seepage
leaching
faulty equipment other hard
surfaces
spillages
amenity areas
3
Pesticide handling areas account for 40-70% of
pesticide contamination of water
 Swedish research
– 1000 biobeds in use
– a significant reduction in pesticides found in surface water
– Systems include a biobed directly under the sprayer, which
stands on a grid or wheel support system.
 UK studies
– suggested inclusion of a ‘drive over or direct’ system and use
of containment around a concrete surface of a sprayer filling
area directing discharge to a biobed.
– 3 systems set up in Lincolnshire at commercial scale with full
monitoring for 2 seasons.
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Pesticide Handling?
Loading
Filling
Mixing
Moving
Washdown
– Interior
– Exterior
Part of the
Application
Process
Disposal
Operation
unless
“applied” in the
field
Small
Quantities
High
Concentration
Large
Quantities
Lower
Concentration
5
Pesticide Handling Area:
Offset or Drive Over
Offset - the handling area separate
from the biobed area
Drive Over - the handling area
directly over the biobed area
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What is a biobed used in the study?
 A hole in the ground with an impermeable
liner and coupled drain-The liner was
necessary for controlling discharge and
sampling outflow.
 2 systems filled with composted mix 50%
by volume straw, 25 % soil, 25% peat free
compost (Biomix) and turfed over
 1 system filled with friable sandy loam soil,
not compacted with grass turf over
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Biobeds challenged by commercial use plus pesticide
contamination artificially TWICE in one season
• The artificial treatments simulated maximum contamination
losses from 16 tank mixes on one day with worse case
practice on each load. This contamination would have
needed a water volume equivalent to 60 Olympic size
swimming pools to meet 0.1g/L
• 6 pesticides were used as artificial contaminantsas
in previous experimental studies. These were
sprayed or ‘spilt’ onto each system in addition to
inadvertent chemical addition from commercial use
• 2 artificial applications June
and September 2002, 55
days monitoring afterwards
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Pesticides used as contaminants
Source types, volumes and concentrations
applied
Contamination
Volume applied Pesticide concentration range
source
(L)
(g/L)
Spray concentrate
0.4
250,000-4,000,000
Spray suspension
4
62,000-1,000,000
Sump rinsate
25
25,000-400,000
Washdown liquid
150
220-3,600
Pesticide
Isoproturon
Chlorothalonil
Dimethoate
Epoxiconazole
Chlorpyrifos
Pendimethalin
Total applied (mg)
12105
12105
2582
1009
5810
16140
Typical concentrations (g/L)
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after artificial application to concrete pad to biobed
(Similar results were found on the soil based
Day after
application
Concrete
runoff
0
1
11
30
55
Biobed
leachate
1
3
10
28
55
system)
Dimethoate Chlorothalonil
Isoproturon
Chlorpyrifos Pendimethalin Epoxiconazole
44277
1970
<2
219
4.5
96807
3810
<2
395
8
140850
5510
5370
282
15.8
77646
1920
1310
64
<2
196790
10600
42400
1390
13.2
8506
1550
2020
293
17.4
<0.5
<0.5
<0.5
<0.5
<0.5
0.3
<0.1
<0.1
<0.1
<0.1
<0.5
<0.5
<0.5
<0.5
<0.5
0.5
0.4
0.4
0.4
0.3
<0.1
<0.1
<0.1
0.6
<0.1
0.6
0.2
0.5
0.5
0.2
10
Typical concentrations (g/L)
after application to Drive-over Biobed
Day after
application
Biobed
leachate
0
3
11
34
55
Dimethoate Chlorothalonil
<0.5
6.0
8.0
<0.5
0.9
<0.1
<0.1
<0.1
<0.1
<0.1
Isoproturon
<0.5
<0.5
<0.5
<0.5
<0.5
Chlorpyrifos Pendimethalin Epoxiconazole
<0.1
0.1
0.1
0.1
0.3
0.3
0.1
0.1
<0.1
0.5
0.6
0.2
0.2
0.2
0.2
Note: No surface figures quoted as the grid did not retain any liquids.
Types,volumes and concentrations applied as for other 2 systems
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Max. concentrations measured (g/L)
Dimethoate
Chlorothalonil
Isoproturon
Chlorpyrifos
Pendimethalin
Epoxiconazole
Concrete intercept to
Drive-over
biobed
biobed
Runoff
Leachate
Leachate
44,277
0.9
15.5
96,807
0.3
<0.1
140,850
<0.5
1.2
77,646
0.7
0.4
205,550
2.3
0.5
9,108
0.8
0.7
Concrete intercept to
soil/grass
Runoff
Leachate
24,800
<0.5
94,600
<0.1
55,900
<0.5
56,300
0.8
107,900
0.8
9,450
0.8
Key Points - Over the two 3-month monitoring periods:
•Input concentrations typically reduced by 10,000100,000 fold
•>1100 individual pesticide determinations from
leachate samples
•87% of leachate determinations had concentration
<0.5g/L (<LOQ)
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Operational Aspects
 Water Storage - Flow Management & Biobed
Moisture
 Drip Irrigation to Biobed and Disposal Area
 Annual Biomix Top-up
 Lining to Biobeds
 Winterisation
 Long Term Biomix Disposal - Residues
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Water management Storage, Distribution and Biobed Moisture
 Offset systems
– Receive rainfall from sprayer area and biobed.
– Storage between bunded sprayer area and biobed beneficial
- probably minimum 1 m3.
– Gives flow control and dilution to biobed.
 Pump from tank supplies liquid to biobed through
drip irrigation
– 400 mm spacing in pipe and row width for even distribution.
– Float switch and time control ‘manage’ system to apply 24mm/ day to biobed
– In 600-700 mm rainfall conditions, biobed moisture appears
stable.
 Biobed- if lined
– Directs all water to secondary storage or direct to field
disposal area via drip irrigation as per biobed.
– Similar systems and controls manage application.
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Is a lining to the Biobed needed?
 Linings were used in the trials
– these allowed study of the liquid flowing.
 Site surveys considering soil types,
watercourses and drains will suggest the need
for a lining.
 In theory pesticide Handling areas not being
used for sprayer washdown may not require a
lining
–
–
–
–
There is a reduced load
Disposal is not taking place
There will be natural dispersal of liquids to the soil strata.
BUT future regulatory uncertainties = if in doubt use a
lining
 A lining will be required where washdown is to
be practised.
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Winterisation
 All parts of any Biobed system must be protected
against frost.
 Maximise protection by below ground installation
– No serious problems were found in the research study.
– Above ground pipe runs should be laid to allow drainage as far as
possible and can be insulated.
 Turf cover may assist protection of drip lines on
biobed.
 Disposal area may benefit with a straw covering.
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Biomix
production and maintenance
 The Biomix
– 50% by volume straw, 25 % soil, 25% peat free compost
– Premixed and composted for 5-6 weeks prior to installation
– When installed turfed over to increase biological activity.
– Mixing is simple-layering on concrete-mixing with tractor
loader and composting.
 Natural activity in the mix causes the mix to
shrink
–
Each year a topping up of the same mix is required-approx.
300 mm depth top up is needed.
 Other organic materials may be appropriate, not
trialled yet in UK.
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Long term biomix issues
 Swedish research suggests 6-8 year life of topped
up biomix.
 Disposal subsequently has been to land - AFTER
ONE YEARS FURTHER COMPOSTING. No
pesticides have been determined after that period
 UK studies have not run for this time scale.
 Disposal if Biomix in UK will be subject to Waste
Disposal Legislation. Contact Environment
Agency, SEPA, EHS NI for guidance.
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Useful Scientific References
Carter, A.D., 2000. How pesticides get into water – and proposed reduction measures. Pesticide Outlook 11(4),
149-157.
Bach, M., Müller, K. and Frede, H.K., 2003. Pesticide pollution from point and nonpoint sources in a small river
catchment in Germany. Proceedings of XII Symposium on Pesticide Chemistry, Piacenza, Italy, June 2003. 801809.
EA, 1998. Quantifying point source inputs of pesticides to rivers – phase 2: development of a decision tree. EA
R&D Technical Report P109. Environment Agency, UK.
Fogg, P., 2001. Biobeds: safe disposal of pesticide waste and washings. British Crop Protection Council
Symposium Proceedings No 78: Pesticide Behaviour in Soils and Water, 217-222.
Fogg, P,, Boxall, A.B.A., Walker A. and Jukes, A.A., 2003. Pesticide degradation in a 'biobed' composting
substrate. Pest Management Science 59, 527-537.
Henriksen, V.V., Helweg, A., Spliid, N.H., Felding, G. and Stenvang, L., 2003. Capacity of model biobeds to retain
and degrade mecoprop and isoproturon. Pest Management Science 59,1076-1082.
Mason, P.J., Foster, I.D.L., Carter, A.D., Walker, A., Higginbotham, S. Jones, R.L. and Hardy, I.A.J., 1999. Relative
importance of point source contamination of surface waters: River Cherwell catchment monitoring study.
Proceedings of XI Symposium on Pesticide Chemistry, Cremona, Italy, September 1999. 405-412.
Rose, S.C., Mason, P.J., Foster, I.D.L., Walker, A. and Carter, A.D., 2001. The design of a pesticide handling and
washdown facility. British Crop Protection Council Symposium Proceedings No 78: Pesticide Behaviour in Soils
and Water,
Torstensson, L. and del Pilar Castillo, M., 1997. Use of biobeds in Sweden to mimimize environmental spillages
from agricultural spraying equipment. Pesticide Outlook 8(3), 24-27.
Torstensson, L., 2000. Experiences of biobeds in practical use in Sweden. Pesticide Outlook
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Reductions of 10,000 to 100,000 fold in
pesticide concentration on discharge
Practical Simple
Solutions
Protecting the
Environment
CAUTION
Seek Regulatory Advice Before Building a Biobed
Contact the Environment Agency's Agricultural Waste Line
0845 6033113