| By the year 2,000 it is estimated that municipal wastewater treatment plants within the United States will produce over 12 million dry metric tons of residual biosolids annually. The long-term beneficial reuse of the biosolids, more commonly referred to as sludges, is currently limited by the trace presence of heavy metals. This investigation examined the biosorptive interaction between municipal wastewater residual biosolids and three regulated metals: cadmium, copper, and lead. The study concluded: (1) there is a high degree of affinity between the metals and the biomass, (2) the material possesses a significant adsorptive capacity, (3) water is not an effective eluent, (4) precipitation and ionic strength may complicate the biosorption phenomenon, and (5) tentatively, that electrokinetics are not an effective means of desorbing cadmium from a biomass slurry. The research reveals that residual biosolids may be a highly effective adsorbent media, indicates that electrokinetics may not be a practical means of elution, and suggests that there is vast potential for future study, investigation, and exploration in this area. |
