Quantification of pathogenic micro-organisms in the sludge from treated hospital wastewater.

The sludge from hospital waste treatment facilities is a potential source of infectious organisms. The average numbers of micro-organisms in the sludge of hospital wastewater in Taiwan were as follows: total count 8.1 x 10(7) cfu g-1 (dry weight of sludge), and 1.4 x 10(6), 3.6 x 10(5), 1.6 x 10(5), 2.2 x 10(5) and 5.5 x 10(4) cfu g-1 (dry weight of sludge) for total coliforms, faecal coliforms, faecal streptococci, Pseudomonas aeruginosa and Salmonella spp., respectively. Salmonella spp. were detected in 37% (10 of 27) of the sludges from hospital wastewaters. Therefore, the treatment of such sludge to reduce pathogenic micro-organisms should be considered.