SELECTED NUTRIENTS AND HEAVY METALS IN SEWAGE SLUDGE FROM NEW JERSEY POTWs

For Publicly Owned Treatment Works (POTWs), selected sewage-sludge nutrient and heavy-metal data were obtained for 1996 and 1997 from the New Jersey Department of Environmental Protection, and the variability of sludge characteristics between and within facilities was examined. The POTWs were grouped into three categories depending on flow rate and percentage of industrial input. Analysis of the data revealed that the nutrient concentrations had not changed much over the past 20 yr, but heavy-metal concentrations had declined markedly due to improved pretreatment methods. The pollutant concentration limits were exceeded in only a few facilities. A high proportion of different means was found in 1996 and 1997 for total Kjeldahl nitrogen, phosphorus, and lead. The variability within 98 facilities ranged 37 47% for total Kjeldahl N, ammonium N, potassium, copper, Pb, and zinc, and variability was above 50% for P and cadmium. Based on the findings, recommendations are proposed for the use of these sewage sludges in land application.