Stabilised mineral–biomass mixtures in groundwork: pilot study

Abstract

Based on fundamental characteristics previously determined, two types of pilot studies were carried out to inform possible future full-scale field application of stabilised mineral—biomass mixtures as components of brownfield restoration projects. To gain a preliminary confirmation of properties, four vertical cylinders containing mixed compacted material were used to represent cylindrical volumes within supposedly continuous mixed emplacements. A 100 t field emplacement based on an alkaline model was constructed within a clay lining. This was regulated by an Environment Agency waste management licence. During 18 months' monitoring, optical surveys detected no significant mechanical movement and the emplacement remained essentially dry despite periods of heavy rain and flooding. No landfill gas was detected in boreholes within the compact mass. Pore water recovered during final excavation contained low but significant levels of ammonia and heavy metals, thus justifying lining. The results should form the basis of development to a full-scale prototype emplacement (∼10 5 t, 1 ha) as a means of assessing this technology for reusing bulk surplus industrial products under regulation.