Municipal solid waste has continued to be a major problem in many nations of the world. The primary methods of treating landfill leachate include physical-chemical and biological treatment processes. Pressure-driven membrane processes, such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis (RO), are among the utmost promising and capable ways for treating landfill leachate. The concentrated leachate created from pressure-driven membrane processes typically represents 13%–30% of total incoming landfill leachate. Concentrated leachate is a dark brown solution with high levels of pollutants. Treating concentrated leachate is extremely difficult, and thus, a combined treatment system is suggested. In the present study, concentrated landfill leachate was treated using a combined treatment technique that included electro-ozonation. The removal efficacies of chemical oxygen demand (COD), color, and nickel were monitored at original pH (7.3) as well as current and voltage of 4 A and 9 V, respectively.
TopLandfill Leachate
Moisture penetrates into the wastes in a landfill after a while we will have the landfill leachate. Characteristics of leachates differ from one landfill to another in the short- and long-terms periods due to differences in climate, hydrogeology, and waste composition (Visvanathan et al., 2000).
Landfill leachates are considered as wastewater that has the strongest environmental impact. The most significant feature of leachates is the high concentrations of particular contaminants.
Urban landfill leachates consist of contaminants that can be classified into four main groups as follows: (1) dissolved organic matter; (2) inorganic compounds such as calcium, potassium, sodium, ammonium, calcium, magnesium, sulfates, and chlorides; (3) iron and heavy metals such as nickel, lead, copper, chromium, cadmium, and zinc; and (4) xenobiotic organic materials (Aziz et al., 2011; Tengrui et al., 2007).
Concentrated Landfill Leachate
Concentrated leachate is a dark brown solution with a high chemical oxygen demand (COD) and a low biochemical oxygen demand (BOD) to COD ratio, which make it difficult to biodegrade (Zhang et al., 2013). Thus, a combined system should be used to treat concentrated leachate. Shengli et al. (2011) investigated the treatment of concentrated landfill leachate via coagulation and fly ash adsorption. He et al. (2015) studied concentrated landfill leachate treatment through oxidation with Fenton’s reagent.