The effect of different percentages of bulking agent (sawdust) on microbial quality of faecal sludge
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Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Water Science & Technology
Abstract
The use of raw sludge spread on land as conditioner and fertilizer has been practised over the years
in urban agriculture. However, this raw sludge (biosolids) is associated with a potential health risk as
a result of the pathogenic microorganisms it contains. The study considered the dewatering of faecal
sludge (FS) mixed with sawdust to produce biosolids that can be applied as manure for agricultural
use. It assessed the bacterial and helminth egg qualities of the biosolids produced from FS-sawdust
mixture. Bench-scale unplanted filter beds were used for dewatering of FS mixed with different
percentages of sawdust. The sludge consisted of public toilet sludge and septage in the ratio of 1:3.
An analysis of variance of the completely randomized design was undertaken and a P-value below
0.05 was considered statistically significant. The sawdust-FS mixture analysed after complete
dewatering showed significant reduction in microbial (bacteria) content (P < 0.05) and helminth eggs,
making the biosolids produced safe for farmers and the environment. The bulking agent improved
the quality of the biosolids, with greatest pathogen removal observed in the 150% sawdust, whilst
the least reduction was recorded in the 0% sawdust (control).
Description
An article published by Water Science & Technology | 67.8 | 2013
Keywords
biosolids, faecal sludge, pathogens, public toilet sludge, sawdust, septage
Citation
Water Science & Technology | 67.8 | 2013