Coagulation–Flocculation Pretreatment of a Partially Stabilized Leachate From a Sanitary Landfill Site at Alhendín (Granada, Southern Spain)

Abstract

Leachate recirculation, biological, and physicochemical treatment processes are used to treat leachate landfill, but all treatment technologies seem to need a combination of two or more methods to obtain an effluent with suitable properties to eliminate environmental problems. In spite of the considerable literature focused on the coagulation–flocculation applied to landfill leachate before biological treatments, most investigations are developed to study different operating variables as leachate characteristics, type, and concentrations of chemical products applied. Two ferric coagulants (ferric chloride and Ferriclar), two aluminum coagulants (PAX-18 and SAL-8.2), an organic coagulant and flocculant (Chemifloc PA-15), several anionic flocculant (Chemifloc A05.L, A10.L, A20L, and A30.L), and a non-ionic flocculant (Chemifloc N01) were used in jar-test experiments to determine the best conditions for the removal of chemical oxygen demand (COD) and total solids (TS) from a partially stabilized leachate collected at a sanitary landfill site at Alhendín (Granada, Southern Spain). The organic coagulant–flocculant PA-15 showed highest (17%) COD and TS removal efficiencies at a concentration of 2 mL/L. All combinations of coagulants and flocculants enhanced the COD removal efficiency. The best results (more than 25% COD removal) were obtained with a combination of ferric or aluminum-based salts in combination with high molecular weight flocculants.