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Sustainable management of metal-contaminated soils in the Campine region

Phytoremediation and bio-energy production

Van Slycken S., Meers E., Tack F.

February 24 2011

Tempus projectFaculty of Bioscience Engineering

Presentation outline

I. Campine regionLocation & history

II. SanitationPhytormediation vs conventional sanitationWhat’s in a name

III. Project overviewExperimental designWorkpackagesConclusion

Tempus projectFaculty of Bioscience Engineering

Tempus projectFaculty of Bioscience Engineering

Belgium

Campine region

I. General Introduction

I. General Introduction

• 19th century - mid 1970- Zn and Pb refineries in ‘the Campine’ (Kempen)- Pyrometallurgical process

• Through the years - Atmospheric deposition- Enrichment of trace elements in top soil layer

• Now- 700 km² (BE + NL), 280 km² (BE)- Cd, Zn and Pb contamination

Tempus projectFaculty of Bioscience Engineering

I. General Introduction

• Soil characteristics in the Campine- Sandy- Acidic

• Consequences- High availability of trace elements- Accumulation of metals in top soils layer- Accumulation of metals in crops- Exceeding legal threshold values of food and fodder crops- High risk for leaching- High risk for ecosystem and human health Action is needed!

Tempus projectFaculty of Bioscience Engineering

II. Sanitation vs phytoremediation

Tempus projectFaculty of Bioscience Engineering

Contaminated soils

• Conventional sanitation• Excavation• Treatment or dumping

• Alternative• Phytoremediation• Usage: bio-energy production

+ In situ treatment+ Large area + Also moderate contamination - Longer sanitation period

+ Also diffuse contamination + No loss of soil texture + Economic valorisable

+ Ex situ treatment+ Small areas+ High contamination level+ Short sanitation period

- Not for diffuse contamination- Loss in soil texture- High cost

Figure from Witters et al. 2009. Bioenerg. Res

II. Sanitation vs phytoremediation

Phytoremediation is a technique that involves the use of plants for the removal of pollutants from the environment or to render them harmless (Garbisu and Alkorta, 2001)

Tempus projectFaculty of Bioscience Engineering

Tempus projectFaculty of Bioscience Engineering

Agricultural landcontaining (elevated)levels of heavy metals

Currently in use for food and feed production

Metal introduction inhuman food chain

FAVVEU

Non-food crops

Phytoremediation crops

Energycrops

Metal sequestration

Stimulated attenuation of soil contamination

Alternative farmer income

Sustainable,renewableenergy production

III.Project overview: user commity

Tempus projectFaculty of Bioscience Engineering

Contaminated soils Industry

Biomass: breeders Biomass: conversion Energy supplier

Agriculture

III.Project overview

III.Project overview• Biomass production

- Annual plants: maize, rapeseeds, cereals- Perennial plants: short rotation coppice- Yields comparable to non-contaminated soils

Tempus projectFaculty of Bioscience Engineering

Data from Van Slycken et al. 2011. Int. J. Phytorem. and Van Slycken et al. 2011. Env. Poll.

III.Project overview• Total extraction of heavy metals

- Biomass production x metal concentration in plant tissues- Maize < rapeseed < short rotation coppice

Tempus projectFaculty of Bioscience Engineering

Data from Van Slycken et al. 2011. Int. J. Phytorem. and Van Slycken et al. 2011. Env. Poll.

III.Project overview• Sanitation period

- Clean up: 5 mg Cd kg-1 soil (values field) - Target: 2 mg Cd kg-1 soil (limit value for sanitation)- Soil density of 1400 kg m-3 and depth 0.25 m

Tempus projectFaculty of Bioscience Engineering

Cd (mg kg-1)

Biomass(ton ha-1)

Cd removal (g ha-1 y-1)

Clean up

Maize 096±0.26 19±3 19±6 > 500

Rapeseed 5 6 27±14 ±300

SRC-willow-shoot 20 4 70 150

SRC-poplar-shoot 18 4.5 80 120

Data from Van Slycken et al. 2011. Int. J. Phytorem. and Van Slycken et al. 2011. Env. Poll.

III.Project overview• Energy conversion

- Maize- Anaerobic digestion- No difference in biogas potential of maize from a contaminated soil

compared to biogas potential of maize from a non-contaminated soil- Metals end up in digestate

- Short rotation coppice- Combustion/ gasification /pyrolysis - No effect of elevated metal concentration in wood on conversion

efficiency- Metals end up in ash or char

Tempus projectFaculty of Bioscience Engineering

Data from Van Slycken et al. 2011. Int. J. Phytorem. and Van Slycken et al. 2011. Env. Poll.

III.Project overview• Economic modelling

- Different angles- Conversion- Farmers- People- Environment (Cd in different pathways/CO2)

- Different studies- NPV- MCA

Tempus projectFaculty of Bioscience Engineering

IV. Phytoremediation - bio-energy crops – metal contaminated agricultural soils?

• A perfect alternative on metal enriched soils• Keeps the farmer ‘in business’• Controlled and safe usage of biomass• Ecological and sustainable

Tempus projectFaculty of Bioscience Engineering

Phytoremediation with bio-energy crops =Sustainable management of

Metal contaminated agricultural soils!

Tempus projectFaculty of Bioscience Engineering