Leaching Studies on a Model Monofill of Water Treatment Plant Residuals

To study the leaching of metals and organic chemicals from Water Treatment Plant (WTP) residuals, a model monofill was constructed. Samples of leachate were collected from the monofill at three different times during a 1-year period. TCLP and total metal analyses were conducted on water treatment plant residual samples. It was found that the concentrations of the 39 regulated constituents were less than the TCLP regulatory limits. Total metal and TCLP test results reveal information regarding of leaching capacities of various metals in the residual. Total metal and TCLP tests show that manganese has the highest leaching capacity, followed by calcium, sodium, aluminum, magnesium, and iron. It was observed that the quantities of calcium in the leachate increased appreciably with time, causing a change in the sequence of leaching of the three samples tested.