Abstract

The effect of a two-step process on the concentration of pathogens and indicator microorganisms in black water (0.9-1% total solids) was studied. The treatment combined auto-thermal aerobic digestion (ATAD) and ammonia sanitisation. First, the temperature of the black water was increased through ATAD and when a targeted temperature was reached (33, 41 and 45.5 degrees C studied), urea was added to a 0.5% concentration (total ammonia nitrogen > 2.9 g L-1). Escherichia coli and Salmonella spp. were reduced to non-detectable levels within 3 days following urea addition at temperatures above 40 degrees C, whereas when urea was added at 33 degrees C E. coli was still present after 8 days. By adding urea at temperatures of 40 degrees C and above, a 5 log(10) reduction in Enterococcus spp. and a 3 log10 reduction in Ascaris suum eggs was achieved 1 week after the addition. With combined ATAD and ammonia treatment using 0.5% ww urea added at an aerobic digestion temperature > 40 degrees C, black water was sanitised regarding the pathogens studied in 2 weeks of total treatment time.

Keywords

ammonia; auto-thermal aerobic digestion; black water; pathogen; urea; sanitisation

Published in

Water Science and Technology
2015, Volume: 72, number: 12, pages: 2112-2121
Publisher: IWA PUBLISHING

SLU Authors

• Nordin, Annika

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Vinnerås, Björn

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all


UKÄ Subject classification

Oceanography, Hydrology, Water Resources


Publication identifier

DOI: https://doi.org/10.2166/wst.2015.432

Permanent link to this page (URI)

https://res.slu.se/id/publ/77182