Decomposition in soil of anaerobically digested olive mill sludge

Abstract

A laboratory experiment was performed during a 120‐day incubation period in order to evaluate changes in the properties of soil amended with the same waste water from olive‐oil processing, either untreated (UVW) or anaerobically digested (ADVW).

The results indicate that organic and inorganic component levels of the soil amended with ADVW do not differ markedly from those of the control. On the contrary, the contents of the same components for the soil amended with UVW resulted much higher, especially in the first days after the addition and sometimes also at the end of the experimental period. A germination test carried out on the soil amended with ADVW did not show any toxicity, while the soil amended with UVW still showed an inhibitory effect after thirty days, after which the toxicity disappeared completely.

Key words:

• Vegetation waters
• sludges
• anaerobic digestion
• soil amendment