Aspects of sustainable development: fly ash deposits, biosolids, contaminated biomass

Abstract

Nowadays, barren and inert fly ash deposits result from power plants operating on fossil coal and occupy large areas of land. They change the landscape, altering ecosystems and dispersing pollutants by precipitations and deflations. On the other hand, from wastewater treatment results sludge waste (biosolids) rich in nutrients. Biosolids are fertilizers with many nutrients and could be recycled to improve soil productivity and stimulate plant growth. A solution was found for the capitalization of two wastes - biosolids and fly ash, both resulting in the same city, Timisoara, Romania. The use of biosolids in fly ash fertilization provides rapid efficiency in topsoil for plant growth. Plant species were chosen considering the possibilities to restrict the metal access in plants, i.e. Lolium perenne species, with reduced harvest, recycled as fodder or, on the contrary, to stimulate accumulation of metals i.e. Onobrychis viciifolia species, with increased harvest, but potentially toxic biomass, processes evidenced by a specific parameter, the coefficient of translocation. Pilot experiments was done in four versions, each in three replicates in a randomized block. The treatment were control and fertilized variant fot each plant species. The new crop installed presents characteristics depending on plant species: with accumulation of metals, i.e. Cr, Cu, Ni, in the shoots, such as in leguminous Onobrychis viciifolia species, resulting vegetation with waste regime. with smaller accumulations of heavy metals, such of grass Lolium perenne, with recycling possibilities in agro-zoo technical field.