Municipal Solid Waste Landfill Leachate Characteristics and Their Treatment Options in Tropical Countries

Abstract

This review assesses the leachate quality from waste disposal sites in tropical climate zone. Through this review, data from 228 leachate samples from 145 waste disposal sites from 18 countries in the tropical region were analyzed. The 12 types of sites were considered for the analysis based on the climatic conditions, age, and the operating condition of the site. Tropical rainforest, tropical monsoon, and tropical savanna climates were identified for the climatic zone classification. Age of site was classified as young and old. The operating conditions were classified as engineered landfill and open dump site. Eighteen leachate quality parameters were included in the analysis. Leachate pollution index indicated that young sites from tropical rainforest zone and tropical monsoon zone have higher pollution potential, while the pollution potential in tropical savanna zone did not demonstrate considerable difference in pollution potential in terms of age of the landfill. Considering the operating method of the sites, open dumpsites pose higher pollution potential. Positive correlation could be seen among biological oxygen demand, chemical oxygen demand, total dissolved solids, and total Kjeldahl nitrogen. pH negatively correlated with organic pollutants as well as heavy metals. Analysis of emerging contaminants present in landfill leachate is limited in tropical region; thus, it is recommended to conduct studies on emerging contaminants. Further, the leachate treatment options considered in tropical region are discussed in this review.

Assessment of surface water quality near municipal Solid Waste dumping facility in Bukoba, Kagera Region, Tanzania

“…Consequently, most areas near landfills are prone to water pollution because of their proximity to MSW dumping sites, and therefore, pose a substantial risk to water users and the environment at large. (Abiriga et al, 2020;Lindamulla et al, 2022).…”

“…Dumping solid wastes in landfills has become the easiest and a less expensive method of disposing of waste in the entire globe (El Mouine et al., 2022). This disposal method has been practiced for many years and is known to be the most old and common technique for municipal waste disposal (Amano et al., 2021; Asibor et al., 2016; Hredoy et al., 2022; Lindamulla et al., 2022; Podlasek et al., 2021; Siddiqi et al., 2022). During landfilling, solid wastes undergo various rapid and gradual changes; biologically physically as well as chemically (Abiriga et al., 2020; Amano et al., 2021).…”

“…During landfilling, solid wastes undergo various rapid and gradual changes; biologically physically as well as chemically (Abiriga et al., 2020; Amano et al., 2021). Consequently, these solid waste materials in landfills slowly start to decompose and release further pollutants in the form of by‐products from its interstitial fluids that may further be transported to surface, sub‐surface, and underground waters to cause pollution (Abiriga et al., 2020; Lindamulla et al., 2022). The most dangerous pollutant from MSW dumps is called “leachate,” which is in the form of liquid and contains various organic and inorganic substances, including heavy metals and other hazardous chemicals.…”

“…The decomposition of solid wastes in landfills is boosted by physical, chemical, and biological processes, and by moisture from precipitation (Abiriga et al., 2020; Amano et al., 2021; Lindamulla et al., 2022). It is however, important to note that the existing waste materials in a particular landfill are in the form of solid, liquid (leachate), and gaseous states (Amano et al., 2021; Asibor et al., 2016; Hredoy et al., 2022; Lindamulla et al., 2022; Podlasek et al., 2021; Siddiqi et al., 2022).…”

Coagulation and oxidation strategies for landfill leachate wastewater

“…Leachates are classi ed as young (less than 5 years), intermediate (5-10 years), and old (more than 10 years) based on the age of the land ll [22,23]. The BOD/COD ratio for young land ll leachates is generally greater than 0.5, whereas for old leachates, it is generally less than 0.1 [3].…”