Helminth eggs inactivation efficiency by faecal sludge dewatering and co-composting in tropical climates.
This study investigates helminth eggs removal and inactivation efficiency in a treatment process combining faecal sludge (FS) dewatering and subsequent co-composting with organic solid waste as a function of windrow turning frequency. Fresh public toilet sludge and septage mixed at a 1:2 ratio were dewatered on a drying bed. Biosolids with initial loads of 25-83 helminth eggs/g total solids (TS) were mixed with solid waste as bulking material for co-composting at a 1:2 volume ratio. Two replicate sets of compost heaps were mounted in parallel and turned at different frequencies during the active composting period: (i) once every 3 days and (ii) once every 10 days. Turning frequency had no effect on helminth eggs removal efficiency. In both setups, helminth eggs were reduced to <1 viable egg/g TS, thereby complying with the WHO guidelines 2006 for the safe reuse of FS.
Koné
Doulaye
D
Swiss Federal Institute of Aquatic Science and Technology (Eawag), Department of Water and Sanitation in Developing Countries (Sandec), P.O. Box 611, Ueberlandstrasse 133, CH-8600 Duebendorf, Switzerland. Doulaye.Kone@eawag.ch
Cofie
Olufunke
O
Zurbrügg
Christian
C
Gallizzi
Katharina
K
Moser
Daya
D
Drescher
Silke
S
Strauss
Martin
M
D000818:Animals; D001200:Ascaris / Q000254:growth & development*; D005243:Feces; D010063:Ovum; D015203:Reproducibility of Results; D012722:Sewage; D014258:Trichuris / Q000254:growth & development*; D014329:Tropical Climate
D012722:Sewage