[Microflora in swine slurry as a parameter in determining the efficiency of deodorizing treatment. II. Treatment with ammonium peroxydisulfate].

Fresh and stored liquid manure from the pig could be deodorized by addition of 2% (w/v) Ammonperoxodisulfate (= APS). This effect was accompanied by a rapid increase of the redox potential up to +400 mV, fluctuating oxygen contents of maximal 0.8 mg/l, a significant decrease of pH below 7.0, a complete decomposition of organic nitrogen compounds and a considerable increase of total nitrogen caused by APS-addition. After 20 days, odour production could be noted again in the fresh slurry sample. It is assumed, that this effect is due to a population of yeasts, vigorously grown up towards the end of the test. The stored slurry sample was shown to be stable with respect to deodorization effect and yeasts could be found in portions lesser than 1%. In the fresh as well as in the stored slurry samples, organisms of the genus Bifidobacterium dominated towards the end of manure handling. In spite of an oxidised substrate it is assumed, that these anaerobic to aerotolerant microorganisms found a microbiotope with a reduced environment inside the flocks, built up by APS-addition. The facultatively anaerobic microorganisms, for the most part of the genus Bacillus, which mainly belong to producers of odorous compounds almost could be eliminated within 20 days at the latest by APS-treatment. It should be focused to prevent a secondary odour production by H2S-forming yeasts. This may be managed in future by an odour-reducing minimal APS-addition under a 2%-application. In addition, the costs of APS-treatment of liquid piggery waste could be reduced considerably.