Removal of Malathion from Aqueous Solutions Using Dried Sludge Produced from Municipal Wastewater Treatment Plants in Daqhlia Government in Egypt

Abstract

Malathion is a dangerous and harmful substance because of its toxicity for humans, animals and aquatic life. Dewatered sewage sludge collected from the disposal area of sludge treatment (drying beds stage) that obtained from wastewater treatment plant in Daqhlia Governorate was thermally treated at three different temperatures 100, 375 and 500°C (which called SLG, SLG1and SLG2 respectively and used to remove malathion from aqueous solution. Experiments were performed at different doses (0.5-1-1.5-2-2.5-3)g of SLG, SLG1 and SLG2 and were shaked at different pH values (2-4-6-8-10-12) at different temperatures. The effect of operational indicators on removal rates has been studied, tested, improved and optimized. The optimum dosage of biomass dried sludge to remove 36.765µg/L of malathion from aqueous solution was 1g/100 mL and the optimum contact time was 30 minutes as the removal efficiency reached to 98%. Adsorption isotherm experiments were performed and showed that the Langmuir model fitted the experimental data well as compared to other models and the malathion adsorption onto SLG followed pseudo second-order model, through which the results obtained to be consistent with the practical results that were implemented.