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Reviving bioremediation options and sustainability: microbial-enhanced biochar opportunities Tony Gutierrez 1 and Frederic Coulon 2 1
School of Engineering and Physical Sciences, Heriot-Watt University, UK
2
School of Water, Energy and Environment, Cranfield University, UK
are nearly 300,000 potentially contaminated sites with an economic value over £1 billion. Heavy metals, together with hydrocarbons, are the most frequent contaminants found at contaminated sites. Similarly, in other countries like China, the fast rate of urbanisation along with huge expansion of manufacturing industry has led to the emergence of significant soil and water contamination problems. In 2014, a national soil survey performed by the Chinese government concluded that up to 16% of all soils, and nearly 20% of all farmlands, were contaminated by organic and inorganic chemical pollutants. In India, recent economic development combined with poor environmental and waste management has also led to rapid land-use change and the emergence of significant soil and water contamination and brownfield problems across the country. Soil provides multiple important functions such as the provision of food and raw materials, a platform for urban development and human well-being, and a filtering and transforming medium for water, nutrients and carbon. Functioning soils are necessary for ecosystem service delivery, climate change abatement, food and fibre production, and freshwater storage. Yet, key policy instruments and initiatives for sustainable development have not fully recognised how contaminated soils compromise the addressing of major challenges such as food and water security, biodiversity loss, climate change and energy sustainability. The presence of contaminated soils causes direct acute and chronic health risks, and limits effective land use for food production, living space and economic development. It is estimated that across the European Union, 350,000 sites are affected by soil contamination. The expectation is that this will continue growing with nearly 3 million polluting activities and estimates of the cost of treatment reaching €4.8 billion (EEA, 2015). In the UK alone, there
20
microbiologist
|
December 2020
Over the past 20 years there has been an increasing drive towards more sustainable treatment-based solutions for contaminated land management as opposed to removal or containment actions, or ‘intensive’ treatments with high requirements for onsite infrastructure, energy and resource use. This has led to the emergence of very successful in situ bioremediation treatments. However, the complexities of both soils and the chemical hazardous mixtures encountered tend to affect the application spectrum and efficiency of bioremediation. Further to this, most of the current bioremediation systems and approaches for treating contaminated soil do not satisfy the end-user needs in terms of efficiency, sustainability and/or cost-effectiveness. Such technologies rely on physical, chemical or bio-based methods, the former two of which are generally prohibitively expensive, whereas all are either non-site-specific, do not work or are quite slow. Thus, the requirement to make contaminated land fit for use places a large economic burden on stakeholders, and there is a pressing need for knowledge, products and new
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