Biosorption of heavy metal ions such as Cd2+ by dead biomass has been
recognized as a potential alternative to existing removal technologies
applied to wastewater treatment. Two bacterial strains were studied i
n the laboratory, Streptomyces griseus and S. clavuligerus, an industr
ial by-product. Both washed and unwashed samples were examined. Foam f
lotation is proposed in this work as the separation stage following bi
osorption. Effective biomass separation was conducted in the presence
of a frother, ethanol. The pH of the solution was a crucial parameter
for flotation and also for metal binding. Other basic parameters of fl
otation examined were the initial cadmium concentration in the dilute
aqueous solution and the quantity of biomass used. A study of zeta-pot
ential measurements of the actinomycetes was carried out under the con
ditions used in the separation; surface tension was also measured. The
se provided useful information on the process. (C) 1994 John Wiley & S
ons, Inc.