Treatment of Piggery Wastes in Portugal: A General Overview

Production and use of piggery wastes in Portugal are described in terms of the number, distribution, type of intensive units, distribution of agricultural crops, stocking density and fertiliser usage. The main problems related to the contamination of water, soil and plants are discussed. Critical pollution problems resultant from the direct discharge of pig slurry in the environment seem to be restricted to localised areas in the country. The large pig unit with limited land is likely to present the greatest problem because of the potential imbalance between the number of animals kept and the land available for slurry spreading. It was estimated that only 12.5 % of the total number of producing units have effluent treatment systems, but most of them present serious technical limitations. The majority of pig production facilities have been developed with little planning and concern for the nuisance and pollutional characteristics inherent with their operation. It appears that farmers are limited by the lack of available technical information, which is vital for the successful approach to the piggery wastes problem in Portugal.