Diagnosis and assessment of the management of sanitary landfill leachates in Portugal

Application of Electrocoagulation with a New Steel-Swarf-Based Electrode for the Removal of Heavy Metals and Total Coliforms from Sanitary Landfill Leachate

“…The research has evaluated the possibility of using treated LL in agriculture, since it is an effluent with a high concentration of ammonia [1,2,25]. The results of our research pointed out that the irrigation practice with treated LL, obtained through EC with SfE, would bring positive environmental advantages since it would reduce the use of water from surface waters and groundwater for the irrigation of green spaces, such as football fields, squares and gardens.…”

“…Sanitary landfill leachate (LL) is a type of wastewater with high loads of organic and inorganic compounds, namely natural and synthetic organics, xenobiotics, ammonia, nitrate, pathogenic microorganisms, and heavy metals. The LL is composed of four different fractions: the natural humidity of the garbage, which increases in the rainy events; the aqueous constitution of organic matter, which is released during the decomposition processes; the bacteria in the trash, which secrete enzymes that dissolve organic matter with liquid formation; and from existing water sources in the area [1].…”

“…The leachate composition is very varied and heterogeneous, but generally contains [1][2][3]: High concentration of dissolved organic matter (as chemical oxygen demand (COD)), ammoniacal nitrogen (N-NH4 + ), nitrate nitrogen (N-N03 − ), chloride (Cl − ), potassium (K + ), sodium (Na + ), calcium (Ca 2+ ), iron (Fe 2+ ), magnesium (Mg 2+ ), manganese (Mn 2+ ), sulfate (SO 4 2− ), hydrogen carbonate (HCO 3 − ), heavy metals (lead (Pb 2+ ), chromium (Cr 3+ ) cadmium (Cd 2+ ), nickel (Ni 2+ ), copper (Cu 2+ ) and zinc (Zn 2+ )) [3,4] and also xenobiotic organic compounds (e.g., phenols, aromatic hydrocarbons, pesticides [5], pharmaceutical compounds and personal use [6], antibiotics [7] and microplastics [8]).…”

“…The disposal of solid wastes in inappropriate places can cause significant negative impacts on soil and water bodies and public health problems, namely due to the groundwater and soil contamination with LL, and; therefore, the treatment of this effluent is necessary and important [4]. In general, the treatment of LL involves the use of biological processes (e.g., activated sludge, stabilization ponds and constructed wetlands) and physicochemical processes (e.g., coagulation, AOPs, ultrafiltration (UF) and reverse osmosis (RO)) [1][2][3]5,7]. However, the most used biological and physicochemical processes have showed variation in efficiency and high operation costs due to the use of UF and RO, and, additionally, the filtered material is returned to the landfill which will become a problem in the future [1,9].…”

“…In general, the treatment of LL involves the use of biological processes (e.g., activated sludge, stabilization ponds and constructed wetlands) and physicochemical processes (e.g., coagulation, AOPs, ultrafiltration (UF) and reverse osmosis (RO)) [1][2][3]5,7]. However, the most used biological and physicochemical processes have showed variation in efficiency and high operation costs due to the use of UF and RO, and, additionally, the filtered material is returned to the landfill which will become a problem in the future [1,9].…”