Sanitising black water by auto-thermal aerobic digestion (ATAD) combined with ammonia treatment

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
    

Global goals (SDG)

SDG6 Clean water and sanitation

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