Hygienization of sludge through anaerobic digestion at 35, 55 and 60 ºC

• Legislation in Sweden and the European Union concerning the use of sewage sludge in agriculture is under revision and future concentration limits for pathogens in treated sludge are likely to be expected. The aim of this study was to evaluate the hygienization of Salmonella, Escherichia coli, Enterococcus and Clostridium perfringens through continuous anaerobic digestion at 35, 55 or 60 ºC as well as to investigate process stability and methane production at 60 ºC. The results indicated that digestion at 55 or 60 ºC with a minimum exposure time of 2 h resulted in good reduction of Salmonella, E. coli and Enterococcus and that anaerobic digestion thus could be used to reach the concentration limits suggested for the EU, as well as in Sweden. Furthermore, stable continuous anaerobic digestion of sludge was achieved at 60 ºC, however with 10% less methane production compared to digestion at 35 and 55 ºC.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Keyword

anaerobic digestion

Methanosaeta

Methanosarcina

pathogen removal

sludge hygienization

Publication and Content Type

art (subject category)

ref (subject category)