[Composting facilities. 1. Microbiological quality of compost with special regard to disposable diapers]

At three different composting facilities, co-composting of used panty diapers with an addition of 10% (weight) to the usual plant input was investigated for various hygienic and microbiological parameters. In nearly any case, a sufficient degree of germ reduction above 99.9% could be observed by determination of reduction rates of B. subtilis spores. The concentrations of "total microorganisms" ranged from 3.9 x 10(5) to 3.3 x 10(11) colony forming units per gram compost (CFU/g) in composts without and from 3.3 x 10(5) to 4.7 x 10(9) CFU/g in composts with panty diapers in the input. The concentrations of "gram-negative bacteria" ranged from 3.3 x 10(4) to 1.3 x 10(9) CFU/g (without panty diapers) resp. from 3.3 x 10(5) to 3.5 x 10(8) CFU/g (with panty diapers), the concentrations of "fecal streptococci" from 1.7 x 10(3) to 7.7 x 10(7) CFU/g (without panty diapers) resp. from 1.4 x 10(4) to 1.4 x 10(8) CFU/g (with panty diapers). Facultatively pathogenic microorganisms showed a broad variety, but no common trend in composts with and without panty diapers in the input. Statistical validity of the determination of contents of microorganisms in compost samples was guaranteed by the collection and analysis of 20 parallel samples with an average sample mass of 10 to 15 kg. From the analyzed quantitative and qualitative hygienic-microbiological parameters, it can be concluded that no negative hygienic-microbiological effects, caused by the addition of 10% (weight) of used panty diapers in the input, have to be expected. Under the aspects of epidemiologic hygiene, composting of used panty diapers together with usual input materials seems to cause no increased risks under the tested conditions. Under the aspect of consumer protection, there is no increase in the risk of infection when using compost produced with addition of panty diapers, compared to compost produced without panty diaper addition to the input.