OLIVE‐MILL WASTEWATER IN ANTIQUITY. ENVIRONMENTAL EFFECTS AND APPLICATIONS

The present study examines the results of archaeological research and all the related information retrieved from the writings of ancient Greek and Roman authors on the use and the environmental effects of olive‐mill wastewater since antiquity. The ancients were aware of the negative effects that the uncontrolled disposal of olive‐mill wastewater had on the environment, while the controlled release was considered to be beneficial for the soil. A predecessor of olive‐mill wastewater is amurca (Latin) or amorge (Greek). Both terms have been used by ancient authors to describe the watery, bitter‐tasting liquid residue obtained when the oil is drained from compressed olives. The role of amurca or amorge is, however, difficult to assess, though it does seem to have been a universal remedy against insects, weeds and plant diseases. On the basis of production and consumption patterns, an attempt was made to estimate the annual olive oil production during the reign of Augustus, which in turn could provide us with an order of magnitude approach for the generated olive‐mill wastewater (amurca). Although there is no evidence that the Romans practised any detoxification technique for reducing the pollutant effects of this waste before disposal, several Greek and Roman writers have described the recycling of amurca into valuable products. Some of the uses of amurca are, in the light of recent research, questionable or not exactly applicable for the present day. However, the pesticidal and fertilizing properties of olive‐mill wastewater have been confirmed by a large number of research studies.