Appropriate technology for soil remediation in tropical low-income countries - a pilot scale test of three different amendments for accelerated biodegradation of diesel fuel in Ultisol

Abstract Polluted land in marginalized regions, such as tropical low-income countries and sparsely populated regions in industrialised countries, demand special remediation strategies that are energy-efficient, locally adapted, economically viable. Strategies for appropriate bioremediation technology under such circumstances can be based on locally available resources in combination with in situ bioremediation technologies to keep energy and material costs down. A pilot scale experiment was set up to test the application of three organic by-products from the local industry (whey, pyroligneous acid and compost tea) to enhance the natural biodegradation of diesel in ultisol. Biweekly applications of 6 mL whey kg−1 soil significantly increased the degradation rate but no positive effect on degradation was found with any of the other amendments. Tropical climate is favourable for biodegradation but many tropical soils are rich in clay which can inhibit the bioavailability of the pollutant which in turn may be decisive for biodegradation kinetics. If low cost is a crucial factor, our results indicate that whey treatment has the potential to be an appropriate technology for treating petroleum-contaminated soils in tropical regions.