Treatability study of leachate generated in a controlled landfill

Abstract

This study evaluated the processes of coagulation/flocculation, activated carbon adsorption and reaction with Fenton to reduce the concentration of pollutants and increase aerobic biodegradation of leachate so that it can be treated by biological process. For the process of coagulation / flocculation, pH (4 to 8) and the concentration of ferric chloride (100 to 600 mg L^-1) were evaluated. For the adsorption on activated carbon (PAC) process, CAP concentrations of 0.1 and 5.0 g L^-1 were evaluated; and for Fenton reaction, COD:H₂O₂ ratio[1: 0.5, 1: 1, 1: 2 and 1: 5] and Fe:H₂O₂ [1 : 3, 1: 5 and 1:10] were evaluated. The aerobic biodegradation of treated leachate by Zahn-Wellens method was evaluated under the best-obtained conditions. The results for coagulation/flocculation was 22.9% removal of COD and 64% of TOC, using 300 mg L^-1 of coagulant and pH equal to 4. For the adsorption on activated carbon, removal of 69% of COD was reached using 5 g L^-1 PAC. For Fenton reaction, removal of 82.3% for COD was reached (for COD: H₂O₂ = 1: 2, Fe: H₂O₂ = 1: 3). The results of aerobic biodegradability showed that only Fenton-treated leachate could increase biodegradability by 12 percentage points compared with raw leachate. The results showed the potential of the Fenton process as a pre-treatment to the biological process.

Keywords:
activated carbon; aerobic biodegradability; coagulation/flocculation; Fenton reaction.