Pesticide Handling Areas, Biobeds and Biofilters

A presentation for farmers, operators and

advisers

V 1.5, 01/2015

Developed for the Crop Protection Association and Agricultural Industries Confederation. The assistance of the ADAS, Environment Agency, SEPA, the Farming Unions and Bill Basford is also acknowledged. This is part of the voluntary initiative to minimise the environmental impact of pesticides

CAUTION

Seek Advice Before Building a Biobed

Contact local Catchment Sensitive Farming Officer or the Environment

Agency

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Contents

Main issues Options for Pesticide Handling AreasSizingManagement and operationLikely costsFinal water disposal

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Background

High levels of some pesticides have been found in surface water

In UK water companies now need to mix or treat water to comply with the EC Drinking Water Directive

Sprayer use, and in particular pesticide handling areas, can be a significant source of water contamination.

The Water Framework Directive identifies priority substances and the need to meet good ecological status thus indicating a further need for compliance.

Sources of pesticides in the environment

Biocides

Atmospheric output,volatilisation

Deposition

Garden & amenity pesticides

Borehole

Residues in water sediments/biota

Residues in soil, water, crop, food, livestock,wildlife

Veterinarymedicines

Sources of pesticides in the environment

Drainage/runoff to surfacewaters

Biocides

Leachingto groundwater

Crop protectionproducts

Consenteddischarges

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Catchment Studies

In UK, Germany and Sweden– 20-70% pesticide load in surface water

catchment is derived from point sources

UK - River Cherwell study 1998-2000– Funded by Bayer CropScience (UK) Ltd– 40% of catchment pesticide load originated

from concrete handling/washdown area

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Pesticides in water

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

faulty equipmentother hardsurfaces

leaching spillages amenity areas

7 Sources of FarmyardPesticide Pollution

17 %

8 %

28 %

12 %

10 %25 %

Mud from tractorwheels

Tractor exteriorwashings

Spillage of containerwashings

Spillage whilemixing

Tank RinseWater

Foil Seals

Results from Year 1 Aventis Cherwell StudyBayer CropScience Cherwell Study

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Concrete Filling Areas

Typical concrete filling areas showing contamination

and run off

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Best Practice - AimsMinimise contamination incidents through

good operational routine– Limit contamination spread from inadvertent

actions– Minimise water volumes (rain and washings) on

handling area– Store empty containers safely and upright after

use– Dispose of containers frequently and safely as

permitted.Through best practice

pesticide contamination of water fromhandling areas can be reduced

by as much as 99%

Always comply with advice

in Codes of Practice

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Sprayer loading area - Options

Concrete – with / without portable bund– with permanent bund

» drained to sump» drained to treatment -biobed or chemical

Soil / grass» Field margin – not bunded

Drive over system» drained to sump» drained to treatment - biobed or chemical

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ConcretePortable bund

– localises any spills– collect and transfer back to sprayer tank.

Permanent bund – ensure area does not receive other drainage water– construct a 100mm high lip/bund around filling area– Direct drainage off concrete away from normal drains to...

ContainmentMinimise rainfallMatch tank size

to collection quantities

Disposalthrough a licensed

disposal contractor..

TreatmentConsider a Biobed

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Portable Bund

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Homemade Splash Catcher

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Soil / GrassWhere site allows, filling the sprayer over a permeable

surface can be useful. Natural breakdown of the pesticides is achieved by microbial action in the soil

BUT– Site >10m away from field drains and watercourses;>50m

from springs and non domestic boreholes, >250m from domestic wells and boreholes

– Prevent soil compaction by use of drive over grid or hardcore

– May need to move site around periodically if compaction occurs

– Avoid use on heavy clay

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Handling Area - with a biobed

A well planned, designed and operated area linked to a biobed will allow pesticides to be retained and degraded by a considerable amount (10,000 -100,000 fold reduction)

A pesticide handling area (mixing and sprayer loading only) may be linked to a biobed without the need for a Groundwater Authorisation from the local Environment Agency.(See sprayer washing note on next slide)

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Sprayer Washdown - Special note

Best Practice for tank washings and sprayer exterior surfaces is to carry this out in the field– Any washings should be discharged onto the

previously sprayed cropped area– Observing maximum dose for that area– Follow Statutory (Green) Code advice

If sprayer washdown is intended at the pesticide handlingarea with disposal to land elsewhere, unless a lined

biobed is being used, a Permitted Area (previously called a Groundwater Authorisation) must be

authorised from the your local Environment Agency

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Biobeds and The Law EA and SEPA support Lined Biobeds as

significant improvement over current practice

NEW Regulatory advice for England and Wales from EA – Groundwater Authorisation (GWA) now referred to

as Permitted Area not required for lined Biobed– Water from lined Biobed can be “irrigated” or re-

used without GWA – Site will have to be registered with EA under Waste

regulation Exemption T32. This is free and can be done on line

– Scotland check with SEPA– Northern Ireland check with EHS

Biobeds

Design, Construction, Use and Maintenance

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Biobed System Components

1 An area (bunded) where the sprayer stands

2 Drainage from that area to a biobed

3 The biobed

4 Drainage from the biobed•either direct to a vegetative area•or to a designated disposal area

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Biobed Design Types

Offset - the sprayer mixing and loading area is separate from the biobed area

– Features:

• Bunded concrete,

• Slope of 1:100 to silt trap

• Drain - to supply biobed

Direct - the sprayer mixing and loading area is directly over the biobed area

– Features• Direct - bunded

• Steel drive over grid or wheel tracks

21Pesticide Handling Areas

linked to BiobedsWhat do the designs look

like?

– Offset - A separate area, bunded concrete, where the sprayer stands and any liquids drain to a biobed

– Direct - A drive over grid all liquids drain directly to the biobed below the grid.

Both designs deliver to a lined biobed under the T32 Environment Agency Exemption

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LINER

Bunded concrete area

OFFSET LINED with disposal area

Turf over

Irrigation by drip or sprinkler

Pump within biobed

Suitable for wash down under T32 Exemption

Where bunded area is roofed then a biofilter or evaporation system may be appropriate, see separate ppt

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Direct Lined Biobed with drive over

BIOBED

DRIVE OVER LINED-with disposal area

Turf over

Steel Grid

Pump

Disposal by drip or

sprinkler

Liner

Suitable for wash down under T32 Exemption

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Fill area, Biobed, Biofilter,Location.. Location.. Location..

Close to sprayer water filling point, chemical store and electricity supply

Away from other traffic / access routes, footpaths etc.

Avoiding collecting extra rainfall - check yard contours, other drain routes and overflow issues

Separate from other drains / watercourses /boreholes(>10m;>50m non domestic borehole;>250m from domestic borehole)

• Groundwater Risks?

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Pesticide Handling Area Dimensions

300 mm

100 mm Drain via silt trap to pump

chamber

W

L

W = Sprayer transport width + 2 m

L = Sprayer length + 1.5 m

Concrete pad

Bund

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Sprayer loading area - Direct

Size - as for offset

Grid - to support total full sprayer weight not compressing liner

Mesh must be removable for biomix annual top-up

Grid size 100 x 40 mm to suit foot safety and soil/mud flow through

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The Biobed -What is it?

Normally a hole in the ground filled with:– a composted mix 50% by volume straw,25 % soil, 25% peat-free compost (biomix)with turf on top

In principle the biobed may be within an impervious container above ground

The hole is lined with an impermeable liner

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Biobeds - Function, location and size

How do they work?– By locking up the pesticides and then providing

conditions for enhanced microbial degradation of the active ingredients over time

Location– A biobed can be sited independently from the loading

area, taking account of local drainage, access, groundwater risks, contours etc.

Size– Where a 24 m, 3000 l sprayer has been used then 5 x 4 x 1 m deep bed has been satisfactory, though

local rainfall and frequency of use will influence final size.

Biobeds should always be at least 1m deep

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Biobeds - Components The biomix materials could be varied from the mix

suggested. Guidance must be sought to ensure required properties exist.

Turf cover over the biomix is vital to encourage the biological activity of the mix and assist in the management of the moisture status of the biomix.

Efficient distribution of the water over the biobed surface is considered critical, drip irrigation is suggested at 400 mm spacing

Drip header

pipe

Good turf growth

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Sizing Summary

Sprayer type Overalllength (m)

Overallwidth (m)

Self propelled 7 5Trailer 7 5Mounted 4 5

Loading area with working allowances, guidance only, best to measure unit on site.

Biobed - excavated in soil, 1 m deep, 300 batter on sides, 5 x 4 m area suggested as suiting most situations.Rule of thumb: Biobed area should be at least two/thirds of the area from which it is receiving liquids. Maximum size needed 1:1 biobed surface area : fill area

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Offset - System PlumbingFrom offset loading area, install silt trap approx 300 l

capacity supplying pump in small chamber, e.g. 0.75 x 0.75 x 1m deep.

Pump, with integral float switch - approx. 40 l/min@6m head, installed to appropriate regulations.

Site all pipe runs for adequate frost protection.Pipe to optional holding tank or direct to drip over biobed.

Excavate biobed and liner with sealed drain as appropriate or central porous tube containing pump. Liner normally to be 1.5mm synthetic membrane thick with no unsealed seams laid on top of a geotextilemembrane (190g/m2) and 25 mm of sand blinding.

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Direct System Design

Design and construct grid to adequately support spray vehicle and ensure safe operator use.– Operator should be kept off biobed surface

for functional and safety reasons. – Allow for grid to be removed in sections for

annual biomix top-up.Construct foundations, as

appropriate, avoiding support on biobed liner if used.

Excavate biobed and liner with sealed drain as appropriate.

Liner as with Indirect system. See further biobed installation notes in design manual

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Biobed - Installation 1Biobed can either be a biomix - straw, soil and

peat-free compost, or loamy soil, note that ratios are given as % by volume

Lining must be sealed to outlet drain effectively with coarse filter over drain inlet, e.g. 6 mm mesh

Where pump is installed within porous tube sufficient clearance must be allowed for float switch activation.

Lining should overlap top of side batter by approx. 300 mm thereby preventing unnecessary rainfall reaching biobed

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Biobed Installation - 2Direct drain to optional tank or small pump

chamber as before, or to pump to final disposal area

Biomix must be composted for 4-6 weeks before use and evenly loaded into hole. Overfill hole to allow for early sinkage

Turf should be laid at time of filling to encourage growth. Turf does not need to be high quality and is laid over the surface of the biomix, watering early to encourage growth

Install drip irrigation, hard hose type best, laid onto the biobed turf surface as well as the final disposal area, lightly anchor drip lines. Drip irrigation better than spray as spray will cause turf kill.

Test pump system before use

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Biobed Management - short term

Biobed irrigation will maintain regular watering of turf and thus control biomix moisture condition

Grass growth will encourage moisture use and thus evapo-transpiration from biobed

Check weekly for condition and function. Investigate any tendency for waterlogging.

Any foliage cut from biobed turf cover to be mulched over biobed area

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Biobed management - long term 1

Where biomix is used, material will degrade and level sinks by approx. 300 mm per year

Biomix top-up annually necessary. Dependent on turf growth, turf may be peeled back (with adequate operator protection) and new mix added to restore level, replace turf.

Check irrigation function

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Biomix material in the hole is required to be exchanged after 5 years use.

Removal of biomix should be done carefully (with appropriate operator protection) to a covered non porous area for further composting for one year. Research suggests any pesticides remaining are fully degraded in that period.

Drainage from this area should be preferentially routed to the replenished biobed.

The spent biomix material may then be spread to land must be in accordance with U10 exemption from Environment Agency.

Biobed management - long term 2

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Water distribution - disposal area

Where drip irrigation used, lay hard hose pipes at 400 mm spacing with drippers at around 1.5 l/h flow rate.– 1-1.5 running hours per day applies 2-4 mm

of water, dependant on equipment used.

Set controls, e.g. level switch and any timers, to achieve this, allowing for override in intense rainfall – buffer available from optional tank if installed

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Typical Costs - OffsetSprayer loading area - depends on

whether adequate concrete present with bund added or new material - range £2000 - £3000

Each chamber £200, pump £90 - 200Biobed, excavation and materials £1000Liner, with drain £1000 - 2000Drip irrigation to biobed and final

disposal, depends on areas £100- £400

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Typical Costs - Direct

Sprayer vehicle grid - range £2000 - £5000

Biobed, excavation and materials / foundations £1000

Liner, with drain £1000 - 2000Each chamber £200, pump £90 - 200Drip irrigation to final disposal,

depends on area £100- 400

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More Information

www.biobeds.info - Detailed information on designs and principles

www.voluntaryinitiative.org.uk then Water leading to

• My area WIYBY

• H2OK? Campaign

• Biobeds

• Catchment Work

Environment Agency– www.environment-agency.gov.uk/ search biobeds

Scottish Environment Protection Agency– www.sepa.org.uk /biobeds

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CPD

BASIS CPD Points AP/032/034/d = 1APNRoSO CPD Points N0340530c = 1AP

Practical Simple Solutions

Protecting the Environment