Metals removal from municipal landfill leachate and wastewater using adsorbents combined with biological method

摘要

Different physical, chemical, and biological treatment methods are used to eliminate heavy metals and pollutants from wastewater and landfill leachate. Sequencing batch reactor (SBR) is a type of biological treatment. This study was conducted to study heavy metals elimination from urban wastewater and landfill leachate using an adsorbent, namely powdered ZELIAC (PZ) that improved SBR. PZ consists of portland cement, limestone, rice husk ash, activated carbon, and zeolite. Response surface methodology and central composite design were used to elucidate the nature of the response surface in the experimental plan and determine the optimum settings of the independent variables [aeration rate (L/min), contact time (h), and leachate to wastewater ratio (%; v/v)] and their reactions. To study the aerobic process, four dependent factors (Fe, Mn, Ni, and Cd) were evaluated as reactions. The results indicated that compared with SBR, PZ-SBR removed heavy metals more efficiently. At the optimum contact time (11.70h), aeration rate (2.87 L/min), and leachate to wastewater ratio (20.13%) in PZ-SBR, removal efficiencies for Fe, Mn, Ni, and Cd were 79.57, 73.38, 79.29, and 76.96%, respectively.