Sanitary and environmental conditions of aquaculture sludge

Sludge from fish farming is a potential organic fertilizer whose land application may be an alternative to final disposal. This article discusses the sanitary and environmental properties of raw sludge from recirculating fish farming as well as sludge treated by anaerobic digestion based on the governing regulations in the United States, the European Union and Chile for the land application of biosolids. The results indicate that raw sludge meets the sanitary requirements for land application of biosolids and that the presence of antibiotics (florfenicol, oxolinic acid, enrofloxacin, flumequine and oxytetracycline) was not detected. The concentrations of each metal in the raw and digested sludge occur at levels far below the maximum allowed by the regulations governing land application of biosolids. The stabilized sludge is consistent with an exceptional quality biosolid, a classification accepted by the Environmental Protection Agency of the United States for those biosolids that can be applied without restriction in any type of soil.