Document Type
Thesis
Date of Award
1-31-1988
Degree Name
Master of Science in Environmental Engineering - (M.S.)
Department
Civil and Environmental Engineering
First Advisor
Hsin Neng Hsieh
Second Advisor
Robert Dresnack
Third Advisor
Su Ling Cheng
Abstract
Wastewater produced in domestic, commercial, and industrial activities often contains significant amounts of metals. This would result in the discharge of heavy metals into the sewer system. Some of the heavy metals can be adsorbed by activated sludge. This may present a problem for the treatment and ultimate disposal of sludge.
The purpose of the research was to determine how much metals can be adsorbed by sludge. Nickel and Lead were selected for this investigation because of their environmental significance. Both belong to priority pollutants considered potentially toxic. Factors affecting the adsorption, such as sludge concentration, metal concentration, mixing condition, temperature, and pH value were studied. Models for predicting the amount of Nickel and Lead in the sludge were also developed.
The results of this experiment show that wide ranges of concentrations of Nickel and Lead (i.e., 0.08 to 44.09 mg of Nickel and 3.73 to 221.28 mg of Lead) can be adsorbed by a gram of activated sludge under different conditions. It was found in the study that most of the adsorption took place in the first five to ten minutes after contect. Adsorption reached equilibrium within two hours. The best Nickel adsorption occurs at pH value of 7, a temperature 35°C, and at a mixing speed of 100 rpm, whereas the optimum adsorption for Lead was at pH 4, 30°C, and also a rotating speed of 100 rpm. Mixed Liquor Suspended Solids (MLSS) to metal ratio would also affect the adsorption capacity. Generally speaking, more Nickel and Lead can be adsorbed at a lower MLSS/metal ratio, however, total metal removal efficiency was reduced at low MLSS/metal ratio. Amoung all the factors affecting Nickel and Lead adsorption, pH is the most important. Temperature and mixing speed are minor controlling factors. Activated Sludge can adsorb 20 to 70 percent Nickel and 80 to more than 99.75 percent Lead with a Nickel concentration of from 1 to 1,000 mg/1 and a Lead concentration of from 100 to 2,000 mg/l. The adsorption capacity of sludge for Lead is greater than for Nickel.
Recommended Citation
Chen, Chi-Yun, "Adsorption of nickel and lead with activated sludge" (1988). Theses. 3252.
https://digitalcommons.njit.edu/theses/3252
