Charakterystyka mikrobiologiczna i mozliwosc wykorzystania osadow sciekowych do produkcji kompostu z oczyszczalni sciekow dla miasta Zielona Gora

The paper presents the sewage sludge microbiological characteristics and the possibility of sewage sludge utilization in compost production where the said sludge would come from a Sewage Treatment Plant in Zielona Góra. The experiment which started on 9 July 2001 and continued until 24 Nov 2001, was carried out at the University of Zielona Góra. The tests included the analysis of sewage sludge collected in Łężyca in Lubuskie Province. The sewage based composts contained additions of sawdust, straw and CaCO₃. In the course of microbiological analysis of fresh sewage sludge and repeated it after composting, the quantities of the following microorganism groups were determined: overall quantity of bacteria (mesophilic), Actinomyces, fungi and other bacteria such as: Salmonella, Escherichia coli, Clostridium perfringens; moreover the parasite ova were counted. The examinations of the sanitary state of fresh sewage sludge and repeated after composting, proved that in the sludge after composting with addition of sawdust and CaCO₃ the quantity of microorganisms decreased from 62.5% up to 100%. Neither the occurrences of bacteria Salmonella or Clostridium perfringens nor parasite ova were noted after four months of sludge composting with addiction of sawdust and CaCO₃. On having compared the three experimental compost products = samples obtained, it can be concluded that the most satisfying compost type was the sludge based compost with addition of sawdust and CaCO₃. The sludge composted with the latter method can be used to fertilize the crop plants (maize, cereals, root plants, etc.) since no pathogenic bacteria nor parasite ova occur therein. On the other hand, the experimental composts produced with addition of straw or straw + sawdust, even though showing a significant decrease in microorganism quantities, proved to have contained Salmonella bacteria. The latter fact disqualifies such composts from utilization for agriculture purposes.

Praca przedstawia charakterystykę mikrobiologiczną osadów ściekowych z miast Czerwieńsk, Sława i Łężyca oraz wyprodukowanych z nich kompostów. Doświadczenie założono 09.07.2001 i trwało do 20.11.2001 r. Przygotowano komposty z osadów ściekowych z dodatkiem trocin, słomy i CaCO₃. W osadach ściekowych i kompostach oznaczono liczebność: bakterii mezofilnych, Salmonella, Escherichia coli, Clostridium perfringens, promieniowców, grzybów oraz jaj pasożytów przewodu pokarmowego. Badanie wykazały, że po procesie kompostowania osadów liczebność mikroorganizmów ulegała redukcji w granicach od 62,5 do 100%. W kompostach z dodatkiem trocin i CaCO₃ nie wystąpiły bakterie Salmonella i Clostridium perfringens oraz jaja pasożytów przewodu pokarmowego. Wyniki te wskazują, że osady ściekowe kompostowane z dodatkiem trocin i CaCO₃ mogą bez obaw być wykorzystywane do nawożenia roślin.