BioCycle December 2008, Vol. 49, No. 12, p. 50
Project assesses opportunities for using marginal and contaminated land for biomass production and soil remediation.
P. Bardos, T. Chapman, Y. Andersson-Sköld, S. Blom, S. Keuning, M. Polland and T. Track

THE increasing importance of biomass for energy production and feedstocks for manufacturing processes (e.g., plastics) has become a worldwide phenomenon. Establishment of nonfood crops for biomass can contribute to policy goals related to renewable energy and carbon management. However, use of land to produce any type of biomass for feedstocks, fuels and energy has become increasingly contentious, with a range of concerns about impacts on food production and habitat (conservation issues). There is also the question about whether some biofuels even have a positive carbon balance at all when the effects of biomass cultivation on nitrous oxide (N2O) emissions from soil are considered. The wider environmental impacts on soil and water and the carbon and resource costs of artificial fertilizers and pesticides also are factors.
A European Environment Agency (EEA) Scientific Committee has questioned the sustainability of existing European Union (EU) commitments to biofuels, and suggested that the EU target to increase the share of biofuels used in transport to 10 percent by 2020 should therefore be suspended. This suggestion was echoed by the European Parliament in September 2008, although it is not yet clear if this argument has been accepted by the European Commission. The EEA opinion was in part based on a sustainable land use report it commissioned, which found that in 2005 an estimated 36,000 km2 of agricultural land in the 25 EU member countries was directly devoted to biomass production for energy use, projected to rise to 190,000 km2 by 2030.
Remediate Land, Produce Biomass
Use of marginal land and secondary resources (such as compost, biosolids and other recycled organics as a soil input; and other resources such as agricultural and forestry residues as a source of biomass) is an emerging opportunity in this biomass debate. Marginal land includes previously developed land, underutilized land and land affected by diffuse contamination. All across Europe there are areas of land that have been degraded by past use, and that are not possible to restore easily or sustainably using conventional methods. Such previously developed land includes areas affected by mining, fallout from industrial processes such as smelting, activities related to forestry and the pulp and paper industry, areas elevated with contaminated dredged sediments, former landfill sites and many other areas where the decline of industrial activity has left a legacy of degraded land and communities. The extent of contamination may not be sufficient to trigger remediation under current regulatory conditions, and there may be little economic incentive to regenerate the areas affected.
In August 2007 the EEA estimated that some 250,000 sites in EU member countries require clean up, and that potentially polluting activities may have taken place at 3 million sites. Numbers are set to rise. A relatively high proportion of these sites remain unused because of problems that include contamination, market failure, cost and planning difficulties. For example, United Kingdom (UK) data from 2005-07 suggests there is 63 km2 of previously developed land in England, of which 35 km2 were vacant or derelict; 17 km2 had been derelict for more than 9 years (sites larger than 2 hectares). A UK regional study in the northwest of England identified 15 km2 of previously developed land, however this area increased to 26 km2 if “under utilized/neglected” land was included.
Data about areas of land affected by diffuse contamination is harder to find. However, in areas like Avonmouth, UK, Kempen, Belgium and the Netherlands, and the Nord Pas de Calais, France, many square kilometers of land are affected by smelter fallout alone, and thousands of square kilometers are suspected to be contaminated in Eastern Europe, e.g. Lithuania and Ukraine.
Food cultivation may not be appropriate on marginal land, for example because of public concerns over the possible presence of soil contaminants. However, not only is marginal land a useful opportunity in many places for biomass production, the substitution of nonrenewable inputs (such as fertilizers) with renewable inputs (such as compost) further improves sustainability – the combination of cultivation and soil rehabilitation could be an integral part of land rehabilitation and risk management in the long term. There may also be further benefits from this kind of land use, e.g., providing a self-funding land management regime, returning economic activity to deprived areas, a long-term improvement in land values and environmental benefits such as carbon sequestration (substitution of fossil carbon resources, and “temporary” sequestration in managed soils), depending on the area. The renewable energy opportunities presented by marginal land use have been recognized by the US EPA.
Of course, set against the scale of agricultural land use overall, the marginal land bank may not seem large. However, using it as a biofeedstock resource is important for several reasons: the land bank may be very significant in particular localities and regions, and these are often areas with economic under-performance; it is an effective means of returning productivity to marginal land; and it brings wider sustainability benefits.
Factors to consider when evaluating marginal land are: 1) Fit for purpose, e.g. manage the risks posed by the contamination; 2) Sustainable, i.e. with small environmental impacts and low use of resources and energy, providing economic benefit rather than stringent costs and wider social benefits; and 3) Attractive to implement, i.e. low cost needing little active management, are readily acceptable to land owners, authorities and the public, stimulating interest. It is possible that long-term use of marginal land for biomass production may at least offset the costs of its management, and potentially even generate local revenue.
The use of recycled organic matter for biomass production on marginal land is likely to fall into two stages. The first is the conditioning and restoration to create conditions suitable for biomass production. The second might be ongoing additions for maintaining soil productivity and fertilizer substitution. Depending on the biomass being grown, this reuse of organic matter such as compost is likely to be far greater in terms of volume required per unit area than the single applications of compost conventionally used for the restoration of marginal land, such as for public amenity use “country parks” and nature areas that has characterized a large amount of marginal land management in the past. This is potentially a significant outlet for recycled organic matter.
“Rejuvenate” Project
Opportunities for combining marginal land reuse, organic matter recycling, risk management and biomass production are being explored by the European “Rejuvenate” project, which will: Evaluate the feasibility of a range of possible approaches to combining risk based land management (RBLM) with nonfood crop land uses and organic matter reuse as appropriate; Develop a decision support tool to identify marginal land for biomass reuse opportunities in the UK, Germany and Sweden; and Assess how verification of their performance might be carried out and identifying what requirements remain for future research, development and demonstration.
“Rejuvenate” includes partners from Germany, the UK, the Netherlands and Sweden and began in October 2008. It is funded, under the umbrella of an ERA-Net SNOWMAN, by the Department for Environment Food and Rural Affaires and the Environment Agency (England), FORMAS (Sweden) and Bioclear BV (Netherlands). The EU ERA-Net SNOWMAN is a network of national funding organizations and administrations providing research funding for soil and groundwater, bridging the gap between knowledge demand and supply (www.snowman-era.net). It is one of more than 70 ERA-Nets (European Research Area-Networks) funded by the EC’s 6th Framework Programme for Research and Technological Development.
The “Rejuvenate” project will identify generic opportunities for and barriers to combining nonfood crop production with risk based land management for economically marginal degraded land (i.e. areas of degraded land that have remained underutilized for protracted periods of time). Opportunities will be categorized based on compatibility with land risk management requirements; land characteristics; biomass applications and markets; and organic matter reuse opportunities.
Opportunities will be assessed for their likely levels of profitability and project risk, know-how requirements, compatibility with other forms of reuse (such as built development) and amenity. For bioenergy crops, particular attention will be paid to “second generation” biofuel opportunities. First generation biofuels such as ethanol from maize tend to process commodities, which can also be used as foods. Second generation biofuels are derived from residues such as straw or the entire crop biomass, e.g. including lignocellulosic components, and are seen as offering higher energy yield per unit land area with lower environmental impacts. Opportunities will also be assessed for their state of development, identifying what verification measures might be required to appraise human health risk management and wider sustainability factors such as carbon sequestration potential and local revenue generation potential.
A combination of considerations will allow an approximate ranking of the likely attractiveness of different RBLM and nonfood crop approaches on the basis of long-term viability. Key factors are likely to be: maintenance of a productive soil (including whatever soil forming processes are needed at the beginning); local climatic and meteorological conditions; meeting crop requirements, particularly with a view to minimizing or substituting nonrenewable inputs and inputs that might have wider environmental impacts such as persistent pesticides; maximizing the “carbon value” of soil management and production, considering permanent sequestration by the substitution of nonrenewable inputs by the biomass produced, and temporary sequestration within the managed site surface; and providing an effective means of combining nonfood reuse with concerns about biodiversity and ecological impacts and public amenity values (such as landscape and accessibility).
Regulations governing restoration of marginal lands using organic waste materials vary from country to country, but two considerations will be important: Quality of the biomass produced, and effective management of risks to human health and the wider environment.
The transfer of potential contaminants from the marginal land (or secondary organic matter inputs) to biomass needs to be avoided, or at least be limited to levels tolerable by downstream biomass use (for energy, fuel or manufacturing feedstock). This consideration is important both from a competitive product quality standpoint, and to avoid triggering a regulatory view that the feedstock generated is a waste or its use of downstream processing needs special pollution control measures.
Risks to human health and the wider environment from the marginal land and secondary organic matter inputs must be managed with local regulatory requirements or better. These risks might include toxic substance transfer to biomass, risks to human health of toxic substances by direct contact with contaminated surfaces or via blowing dust. There are also other environmental risks such as nitrate migration to groundwater. Risk management needs will be highly site and material specific. It is also likely that pragmatic risk management strategies will be adopted – driven by finding the approach that is most likely to win regulatory acceptance, and is most economically feasible, both of which are vital to securing rapid reuse of the marginal land. Case studies from the “Rejuvenate” project will be reported on in a future issue of BioCycle.
Paul Bardos and Tony Chapman are with r3 Environmental Technology Ltd, a research consultancy; Yvonne Andersson-Sköld works at the Swedish Geotechnical Institute in Göteborg; Sonja Blom works with FB Engineering AB in Sweden; Sytze Keuning works with Bioclear BV in the Netherlands; Marcel Polland and Thomas Track work at DECHEMA, the Society for Chemical Engineering and Biotechnology in Germany.