A Critical Review of Biological Processes and Technologies for Landfill Leachate Treatment

Abstract

The most common method to deal with the huge production of municipal wastes is still the disposal in landfills which, however, generates a leachate with high contents of organic and nitrogen pollutants. Requirements must be fixed by law to control leachate release from such landfills, and effective treatment processes and technologies must be applied to reduce its impact on the environment. Biological processes for leachate treatment are discussed in this review, in the former part of which attention is paid to leachate formation and its qualitative and quantitative features, while the latter deals with the state‐of‐the‐art of the most effective biotechnological treatments presently employed. Processes, alternative methods, and technological improvements are compared, with special focus on novel technologies to remove nitrogen pollutants from leachate, highlighting advantages and drawbacks of each treatment.

Novel and Conventional Technologies for Landfill Leachates Treatment: A Review

“…The non-homogenous nature of the pollutants is due to the numerous biochemical reactions diffuse within the waste piles that contribute to leachate generation. According to other studies [14,15], generally the leachate composition ranges are 100-50,000 mg/L chemical oxygen demand (COD), ,000 mg/L biological oxygen demand (BOD), 5-11 pH, 13-5000 suspended solids (SS), and 10-13,000 mg/L nitrates (NH 4 -N), which are functions of the numerous factors that influence the compound quality; the most important factor is the waste age. Indeed, time influences the COD, BOD 5 and the ratio of BOD 5 :COD, since they decrease with the time while the pH value increases [15].…”

“…As reported by other reviews, conventional treatments are not sufficient to obtain high performances in contaminant removal because no flexible and universal way to treat landfill leachate exists; instead, it is specific, case by case [13,14]. Taking into account the leachate age, season, climatic conditions, regulation criteria and pollutant concentration, leachate treatment plants are forced to integrate chemical-physical and biological stages [18] which ameliorates drawbacks and contributes to a higher treatment efficiency [35].…”

“…This aspect plays a key role in implementing treatment processes, since there is no single treatment available for all landfill leachate typologies [14]. The non-homogenous nature of the pollutants is due to the numerous biochemical reactions diffuse within the waste piles that contribute to leachate generation.…”

“…Managerial variables are the ones that affect mostly leachate production, such as waste disposition methods or the land slope, while the post-closing phase allows physical and geometrical parameters to be constant and clearly definable. As a result, leachate composition and flow may vary considerably case by case [14]; hence, specific surveys are required for each specific disposal site in order to implement the most suitable leachate treatment plant.…”

Mono and Poly-Cationic Adsorption of Heavy Metals Using Natural Glauconite

“…Heavy metals belong to the group of most dangerous pollutants and exhibit a negative impact on human health and ecosystems [1]. Their harmful effect is related to their ability to accumulate in tissues of living organisms, which causes numerous disorders.…”