Solid waste management and bioelements in soil.
Two studies are reported in the field of solid waste management. The first concerns heavy metal migration below a landfill site. The results show that total and leachable heavy metal concentrations are more variable in refuse than in soil samples, as refuse is not homogeneous but can be influenced by local conditions and the seasons. In the soil below refuse, the concentration of total metals is low and similar to control soil samples, whereas leachable metals behaved differently in the two drillings, their mobility depending on soil characteristics. The bulk of heavy metals, however, remains immobile. The second study regards the utilization of compost as a filter bed for pig slurry to reduce its pollution load hence enriching the compost of the nutrients it lacks. A pilot plant was installed utilizing pressed straw bale containers filled with compost through which pig slurry was filtered. The filtering tests demonstrated a reduction of the pollution load of slurry and at the same time evidenced the possibility of utilizing the entire filtering system as a fertilizer to improve compost, with heavy metal concentration tolerance limits lower than the ones proposed at a national level to prevent environmental pollution.