| Abstract |
| This study aims to compare the maximum total phosphorus adsorption capacity (MPAC) of dewatered sludges, which were generated from four purification plants for the adsorption of T-P from effluent of municipal sewage treatment plant. The MPAC from the Langmuir isotherm plot was ranged from a low of 2.3 mg T-PIg sludge(P-3 sludge) to a high of 7.7 mg T-P/g sludge(P-4 sludge) for potassium dihydrogen phosphate solution(PDP). In the effluent of municipal sewage treatment plant, the MPAC showed a similar to MAPC for PDP. The value of MPAC lower in P-2 and P-3 sludges, which were conditioned with polyacrylamide (anionic charge) than in P-I and P.4 sludges, indicating that the polyacrylamide will affect sludge characteristics and accordingly affect the T-P adsorption capacity. Meanwhile, the P-3 sludge has the highest aluminum content, followed by P-4, P-I and P-2. The highest MPAC was obtained in P4 sludge for potassium dihydrogen phosphate solution and effluent of municipal sewage treatment plant. Although P-3 sludge was contained about I 16g aluminum/kg sludge which was higher than 40% in P-2 sludge, the MPAC was lowest. However, the MPAC highly dependent on the aluminum content in dewatered sludges except the P-3 sludge. Also, during the adsorption process of T-P, the decrease of T-P concentration in solution accompanied with an increase in pH and concentrations of anion such as sulfate and chloride. The results indicated that ligand-exchange is shown to be the dominating mechanism of T-P onto the dewatered sludges. |
|
|
| Key Words |
| Dewatered sludges, T-P adsorption capacity, Sulfate, Chloride aluminum, Langnmuir isotherm |
|
|
|
|
|
PDF