Microflora inhabiting raw sewage, secondary effluent and dewatered sludge in Ibb, Yemen republic

الملخص EN

The microflora of raw sewage, secondary effluent and dewatered sludge (manure) were investigated.

Microbial total counts were relatively higher in raw sewage than in secondary effluent and dewatered sludge.

A mongst the bacterial groups recorded in the present investigation, faecal Streptococcus, Streptococcus pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus and Escherechia Coli were found in the three substrates at 37 oC.

On the other hand, Salmonella spp.

were isolated from raw sewage and secondary effluent, but Shigella spp were isolated only from raw sewage.

Some of these bacterial species can produce toxins and cause infections directly or indirectly through contact with sewage sludge.

The most common fungal species in the tested substrates on Sabouraud’s agar, without cyclohexamide at 28oC were : Aspergillus flavus, A.

fumigatus, A.

niger, Acremonium strictum, Aspergillus.

terreus, A.

versicolor, Cladosporium cladosporioides, C.

herbarum, C.

oxysporum, Gibberella fujikuroi, Cohliobolules hawaiiencsis, Fusarium solani, F.

oxysporum, Penicillium chrysogenum, Geotrichium candidum and Scopulariopsis brevecaulis.

On Sabouraoud’s dextrose agar with cycloheximide the most frequently isolated species were: Aspergillus flavus, A.

fumigatus, A.

niger, Gibberella fujikuroi and Geotrichium candidum.

Some pathogenic fungi were also,isolated, but in various incidences and numbers such as Chrysosporium tropicium C.

indicum, C.

parvum, Geotrichum candidum, Histoplasma capsulatum, Microsporum canis, M.

gypseum and M.

manginii.