Spontaneous emission of phosphane from animal slurry treatment processing.

The degree of the emission of the mutagenic phosphane from animal slurry have become an issue of hygienic which so far has not been investigated. This work clearly detects spontaneously emitted free phosphane from animal slurry for the first time and correlates the degree of its emission with different disposal technologies. The subjects of the investigations are the simple storage process and processes involving biogas plants for the digestion both of pig and cattle slurry. Pig slurry generates about one magnitude more phosphane than cattle slurry. The maximum concentration detected in putrefaction gas was 14621 ppt(v/v). Putrefaction gas samples from fresh fecal slurry in primary (mediary storage) tanks followed by storage basins and sedimenters contains the highest concentrations. The mainly methanogenic biogas process generates the smallest concentrations but the highest fluxes of phosphane. Fluxes and concentrations in open basins are significantly higher during summer than in winter. The correlation of phosphane and dimethyldisulfide concentrations indicates that primary lytic processes play a role in the liberation of phosphane. Individual samples of the emission in air give a maximum value of 35 ppt. By comparison, measurement of phosphane in Hungarian digester gas from municipal sewage treatment show that maximum concentrations could be some orders of magnitude higher. Therefore the data base for phosphane from animal slurry must in future be expanded. The results of analysis so far achieved cannot be interpreted from either a human or veterinary medical viewpoint.