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

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Diffuse Point Source Non-crop use

drift tank filling roads

drainflow waste disposal pavements

surface flow washings railways

interflow/baseseepage

faulty equipmentother hardsurfaces

leaching spillages amenity areas

Pesticides in water: sources of contamination

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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 FillingMixingMoving

Washdown– Interior– Exterior

Part of the Application Process

Disposal Operation unless “applied” in the field

Small Quantities

High Concentrati

on

Large Quantities

Lower Concentrati

on

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

• 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

• 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 0.1g/L

• 2 artificial applications June and September 2002, 55 days monitoring afterwards

8 Pesticides used as contaminants Source types, volumes and concentrations

appliedContamination

sourceVolume applied

(L)Pesticide concentration range

(g/L)Spray concentrate 0.4 250,000-4,000,000Spray suspension 4 62,000-1,000,000Sump rinsate 25 25,000-400,000Washdown liquid 150 220-3,600

Pesticide Total applied (mg)Isoproturon 12105Chlorothalonil 12105Dimethoate 2582Epoxiconazole 1009Chlorpyrifos 5810Pendimethalin 16140

9 Typical concentrations (g/L) after artificial application to concrete pad to

biobed

(Similar results were found on the soil

based system)Day after

application Dimethoate Chlorothalonil Isoproturon Chlorpyrifos Pendimethalin EpoxiconazoleConcreterunoff

0 44277 96807 140850 77646 196790 85061 1970 3810 5510 1920 10600 155011 <2 <2 5370 1310 42400 202030 219 395 282 64 1390 29355 4.5 8 15.8 <2 13.2 17.4

Biobedleachate

1 <0.5 0.3 <0.5 0.5 <0.1 0.63 <0.5 <0.1 <0.5 0.4 <0.1 0.210 <0.5 <0.1 <0.5 0.4 <0.1 0.528 <0.5 <0.1 <0.5 0.4 0.6 0.555 <0.5 <0.1 <0.5 0.3 <0.1 0.2

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Typical concentrations (g/L) after application to Drive-over Biobed

Day afterapplication Dimethoate Chlorothalonil Isoproturon Chlorpyrifos Pendimethalin Epoxiconazole

Biobedleachate

0 <0.5 <0.1 <0.5 <0.1 0.3 0.63 6.0 <0.1 <0.5 0.1 0.1 0.211 8.0 <0.1 <0.5 0.1 0.1 0.234 <0.5 <0.1 <0.5 0.1 <0.1 0.255 0.9 <0.1 <0.5 0.3 0.5 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)

Concrete intercept tobiobed

Drive-overbiobed

Concrete intercept tosoil/grass

Runoff Leachate Leachate Runoff LeachateDimethoate 44,277 0.9 15.5 24,800 <0.5Chlorothalonil 96,807 0.3 <0.1 94,600 <0.1Isoproturon 140,850 <0.5 1.2 55,900 <0.5Chlorpyrifos 77,646 0.7 0.4 56,300 0.8Pendimethalin 205,550 2.3 0.5 107,900 0.8Epoxiconazole 9,108 0.8 0.7 9,450 0.8

Key Points - Over the two 3-month monitoring periods:

•Input concentrations typically reduced by 10,000-100,000 fold

•>1100 individual pesticide determinations from leachate samples

•87% of leachate determinations had concentration <0.5g/L (<LOQ)

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Operational Aspects

Water Storage - Flow Management & Biobed Moisture

Drip Irrigation to Biobed and Disposal Area

Annual Biomix Top-upLining to BiobedsWinterisationLong 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

2-4mm/ 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

liningA lining will be required where washdown is to

be practised.– It may be beneficial anyway to control all liquid flow in order to

manage the distribution to a disposal area.

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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.

16Biomix

production and maintenanceThe 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 ReferencesCarter, 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 rivercatchment in Germany. Proceedings of XII Symposium on Pesticide Chemistry, Piacenza, Italy, June 2003. 801-809.

EA, 1998. Quantifying point source inputs of pesticides to rivers – phase 2: development of a decision tree. EAR&D Technical Report P109. Environment Agency, UK.

Fogg, P., 2001. Biobeds: safe disposal of pesticide waste and washings. British Crop Protection CouncilSymposium 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' compostingsubstrate. 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 retainand 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. Relativeimportance 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 andwashdown facility. British Crop Protection Council Symposium Proceedings No 78: Pesticide Behaviour in Soilsand Water,

Torstensson, L. and del Pilar Castillo, M., 1997. Use of biobeds in Sweden to mimimize environmental spillagesfrom 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