Marta Marmiroli1, Brett Robinson2, Nanthi Bolan3, Brent Clothier2, Steve Green2, Carlo van den Dijssel2, Nelson Marmiroli1.
1-HortResearch & 3-Massey University, Palmerston North, New Zealand2-University of Parma, Parma, Italy
A Decision Support System for the A Decision Support System for the phytophyto –– treatment of treatment of dairy effluentdairy effluent
Phytoremediation as a for of “Phytoprevention”
PhytoremediationPhytoremediation can come can come handytohandyto solve pollution solve pollution problems already existing. Is problems already existing. Is there a way it can help to there a way it can help to prevent these problems to prevent these problems to show up?show up?
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Agriculture is a Agriculture is a startngstartng pointpoint
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harleybetts.comAtlanta, 2005
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Dairy effluent disposal: current practice
• Directly into waterways
• Onto pasture to improve growth
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Dairy effluent in the environment
• NO3 – 100 mg/kg – groundwater contamination
• NH4 – 50 mg/kg – surface runoff
• K – 200 mg/kg – induced Mg deficiencies
• Pb, Cu, Zn traces – accumulation in soils and/or crops
• DOC – 100 mg/kg – facilitate metal leaching
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Increasing N-loading on waterways
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Financial incentives for sustainable effluent disposal
The Resource Management Act (1991)
Purpose – (1) The purpose of this Act is to promote the sustainable management of natural and physical resources
(2) In this Act, “sustainable management” means managing the use, development, and protection of natural and physical resources … while
(c) Avoiding, remedying, or mitigating any adverse effects of activities on the environment.
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Could fast-growing tree species be used?
Rainfall re-evaporated from leaves
contaminant degradation & metal stabilisation
Contaminant and water extraction
Water & contaminant leaching
Groundwater movement off site
Evapotranspiration
Evapotranspiration
Rai
nfal
l
Rai
nfal
l
Plant uptake of groundwater
• Tolerant to local conditions
• Rapid growth
• High water use
•Extract or enhance the degradation of the target contaminant
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Other problems related to Agriculture and farming
can span from…
…rough Bison in US
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11/06/2005 17
Celestial Lagoon
So it is important to train the cows when to urinate
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to disciplined cows in New Zealand
Leaf
Dry
Mat
ter (
tonn
es /h
a)0
1
2
3
4
Control Effluent irrigated
effect of dairy effluent on growth
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Salixbranchesand leaves are palatablefodder forcows.They alsosupplymineralsas Mg and Ca
Mmhuu!
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Green house experiment
•• 18 18 lysimeterslysimeters•• 12 12 plantedplanted withwith SalixSalix kanayunagykanayunagy clonesclones (a (a
speciesspecies veryvery resistantresistant toto pathogenspathogens))•• 6 control non 6 control non plantedplanted lysimeterslysimeters•• TreatmentsTreatments: 2L : 2L effluenteffluent a day=T1, 1L a day=T1, 1L effluenteffluent a a
day=T2, 0,5L of day=T2, 0,5L of effluenteffluent a day=T3, a day=T3, onlyonly water=T0; water=T0; threethree replicatesreplicates forfor eacheach treatmenttreatment
•• EffluentEffluent collectedcollected fromfrom MasseyMassey dairydairy farmfarm N°4, N°4, PalmerstonPalmerston NorthNorth, NZ, NZ
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•• Water Water forfor irrigatonirrigaton waswas suppliedsupplied accordingaccording toto the the seasonalseasonal and and growthgrowth needsneeds..
•• EffluentEffluent waswas appliedapplied forfor 100 100 daysdays, after , after leavingleavingthe the plantsplants stand stand forfor 35 35 daysdays in the in the bucketsbuckets forforacclimationacclimation
•• WeeklyWeekly activitiesactivities: : collectcollect leachatesleachates, , measuremeasureshootshoot lengthlength, , countcount leavesleaves, , collectcollect leavesleavessamplessamples
•• Destructive final sample: 14 Destructive final sample: 14 Feb.Feb. 20052005
Green house experiment
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Effect of effluent on willow biomass
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1 2 3 4
Daily effluent application
Tota
l dry
bio
mas
s (k
g)
4 mm2 mm1 mm0 mm0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1 2 3 4
Daily effluent application
Tota
l dry
bio
mas
s (k
g)
4 mm2 mm1 mm0 mm
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NO3 and NH4 from lysimeterlecheates after 100 days of effluent
appication
NO3 tot
0
100
200
300
400
500
600
p1 p0.5 np0p0
.5p0
.25np0.5 p0p0.25np0.5 p1 p0np0.5 p0.5p0.25
np0p0
.5 p1
lys
tota
l NO
3 (m
g)
NH4 tot
0
2
4
6
8
10
12
14
16
18
p1p0.5 np0p0.5p0.25np
0.5 p0p0
.25np0.5 p1 p0np0.5
p0.5p0.25
np0p0.5 p1
lys
tota
l NH
4 (m
g)
Total NO3 is almost 100 times higher than total NH4
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Critical questions
•• Poplar and willow (Poplar and willow (phreatophytesphreatophytes) are palatable ) are palatable forage species that have a positive growth forage species that have a positive growth response to dairy effluent.response to dairy effluent.
•• What area of trees is needed to dispose of the What area of trees is needed to dispose of the effluent?effluent?
•• How do the costs compare to pasture disposal?How do the costs compare to pasture disposal?
•• What are the likely longWhat are the likely long--term effects? term effects?
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Decision Support System
• Supple technical program that works for gold, and works just as well for wastewaters: how to dispose of “something” (metal, nutrient, ecc..) and have back a revenue
• For dairy shed effluent we can just say “pecunia non olent”
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CONTAMINANTMOVEMENT
-soil distribution-leaching-plant uptake
CLIMATE
SUBSTATE
PLANT
MANAGEMENT
ECONOMIC
COSTS
-phytorem.-alternative-inaction
PHYTO - DSS
CONTAMINANT
Ease of use
Accuracy
DSS design
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M2+
M2+
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Transpiration “T (L dTranspiration “T (L d--1 1 )”)”
ContaminantContaminantin soil solution “C (mg L in soil solution “C (mg L --11)”)”
The process of phytoextraction
ΦRoot
Adsorption Factor
Root fractionRoot fraction““RR””
( )( ) dzdtztCztCtTztRtM Rz t
∫ ∫=0 0
`)`(`)()`,()( φ
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Trees PasturezP << zS
Rootdepth, zP
N-Humus
N-Litter
NH+4 NO-
3
N-Plant
C-Litter
Rain
N-leaching
Denitrification
VolatilisationRespiration
C-Humus
HARVEST
NitrogenNitrogen in in soilsoil isis affectedaffected byby plantsplantsrootsroots, , microbesmicrobes, , humichumic substancessubstances, DOC , DOC
and and climateclimate
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Parameterisation: climate
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Parameterisation: substrate
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Parameterisation: contaminants
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DSS
Parameterisation: plant properties
plant [contaminant] x plant biomass .
total water-use x soil-solution [contaminant]R.A.F. ≈
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DSS
Parameterisation: economic variables
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DSS
PhytoDSS - outputs
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Conclusions
•• Each farm is unique in the characteristics of soil, Each farm is unique in the characteristics of soil, agronomical practice and climateagronomical practice and climate
•• The DSS is a mechanistic model that takes into The DSS is a mechanistic model that takes into consideration the main variable affecting consideration the main variable affecting Nitrogen and metal leaching into soil and water Nitrogen and metal leaching into soil and water due to wastewater disposal onto agricultural landdue to wastewater disposal onto agricultural land
•• Existing models may not be suitable for dairy Existing models may not be suitable for dairy effluents because they do not consider DOC and effluents because they do not consider DOC and N N
•• There may also be concerns for metals transport There may also be concerns for metals transport from soil to groundwaterfrom soil to groundwater
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Willows may provide an exposure pathway for Cd
Pastur
e
Yeogi
Kawa
Verone
seShin
sei
Crows n
est
Yunna
nens
is
Toa
Booth
Kinuya
nagi
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0 D
C
B B
A A A A A A
Leaf
[Cd]
μg
g-1
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Future challenges: determining nutrients and metal contents of plant used for wastewater
disposal
0
2
4
6
8
10
12
14
Soil Cd=0.3 μg/g
Leaf cadmium concentrations in 15 willow clones
Clone Number
Leaf
cad
miu
m c
once
ntra
tion
(µg/
g)
1214 11 13 9 8 6 2 4 10 1 15 7 5 3
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Preliminary SEM/EDX screening of sections from willow branches
C O Ca
CdZnKCuMgAtlanta, 2005
C O
Ca CdZnKCu
Mg
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Take home message
•• DairyDairy farmsfarms are getting are getting largerlarger and the and the problemproblem of of disposingdisposing of of wastewaterswastewaters isis becomingbecoming urgenturgent
•• GreenGreen--househouse lysimeterslysimeters experimentexperiment withwith willowwillowstandsstands can simulate can simulate leachingleaching and and plantplant growthgrowthunder under dairydairy shedshed effuenteffuent irrigationirrigation
•• Data from Data from greengreen--househouse experiment are experiment are instrumental to shape a suitable DSS to help instrumental to shape a suitable DSS to help farmers to follow an environmental sound and farmers to follow an environmental sound and costcost effectiveeffective disposaldisposal of of wastewaterswastewaters
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Acknowledgements
•• OECD ( OECD ( OrganisationOrganisation forfor EcononomicEcononomic CoCo--operationoperation and and DevelopmentDevelopment) ) fellowshipfellowship
•• HortRsearch Environmental GroupHortRsearch Environmental Group in Palmerston North (Brent in Palmerston North (Brent Clothier, Brett Clothier, Brett RobinsonRobinson, , SteveSteve Green, Carlo Green, Carlo vanvan denden DijssenDijssen, Tessa , Tessa MillsMills, , SivaSiva SivakumaranSivakumaran, , IanIan McIvorMcIvor, , RogerioRogerio ChicotaChicota, Iris , Iris VokclerVokcler, , HamyHamy ((visitingvisiting studentstudent fromfrom MasseyMassey University) and University) and MeryMery--BethBethKirkhamKirkham ((visitingvisiting professor professor fromfrom Kansas State Kansas State UniversityUniversity))
•• Prof.Prof. NanthiNanthi BolanBolan and and allall the staff in the the staff in the SoilSoil ScienceScience lab (lab (IanIan, Bob, , Bob, MikeMike, , JagraiJagrai, Rita) at , Rita) at MasseyMassey UniversityUniversity
•• Prof.Prof. Nelson Nelson MarmiroliMarmiroli and prof. Elena Maestri at Parma University, and prof. Elena Maestri at Parma University, ItalyItaly
•• USEPA travelling USEPA travelling grantgrantAtlanta, 2005
