Heavy metal variability of different municipal sludges as measured by atomic absorption and inductively coupled plasma emission spectroscopy

Abstract Six sludge streams at two sewage treatment plants were monitored for three months to determine variability, degree of magnification, and generation rates of heavy metals and nutrients. Measurements of As, Ba, B, Cd, Cr, Cu, Pb, Hg, Mo, Ni, Se, Ag, Zn, K, N, P, ammonia, total solids, and volatile solids showed that most variability was related to the type of sludge (primary sludge, waste activated sludge, digested sludge, dewatered sludge), and to a lesser extent, to the day‐to‐day changes of a particular sludge stream.