Impact of Pretreatment on Sludge Content of Heavy Metals

The Camden County Municipal Utilities Authority (CCUMA) is expanding and upgrading its wastewater treatment facilities to secondary treatment. Approximately 100 dry tons of sludge per day will be generated by two regional facilities. The concentration of heavy metals in the municipal sludge is critical in determining the environmental acceptability of land-based sludge disposal alternatives and in assessing suitable land application rates. An extensive industrial survey and an industrial and stormwater sampling program were conducted for cadmium, chromium, copper, lead, mercury, nickel, and zinc. Cadmium was the only metal found to be contributed primarily from industrial sources, and therefore the only metal that would be significantly removed by industrial pretreatment.