Composting leachate: characterization, treatment, and future perspectives

Abstract

The increasing production of waste has led to one of the major environmental challenges of today: waste management. A solution to this problem is the composting of organic wastes. While the composting process transforms organic wastes into biologically stable compost, large amounts of highly contaminated leachates that present a direct risk to the environment are also produced. First off, this review discusses the origin and nature of contaminants found in composting leachates. In a general perspective, composting leachates are characterized by the presence of high concentrations of moderately biodegradable organic matter and nutrients and contain toxic pollutants such as heavy metals and plasticizers. Treatment technologies that have been studied are subsequently reported and discussed (treatment efficiencies and operating costs). This review highlights the lack of available solutions to efficiently remove all contaminants found in these leachates, which is a major concern considering the increasing number of composting facilities. While both, membrane bioreactors and reverse osmosis, show promising results with NH 4 , COD and TSS removals of [ 70, [ 85 and [ 99.9%, respectively, the resulting effluent remains hazardous for the environment. Further studies are required to assess the use of a combination of biological and advanced oxidation process for the production of a safely disposable effluent.

Biogas Generation through Anaerobic Digestion of Compost Leachate in Semi-Continuous Completely Stirred Tank Reactors

“…Lim et al [37] observed a decrease of biogas yield for organic loads that were over 4 kg COD /m 3 d. On the contrary, other works identified much higher OLR values as the most profitable for biogas production [10]. The literature reports are quite different also in regards to the methane content of biogas originating from the anaerobic digestion of composting leachate [36]. These differences, probably, depend on the reactor type and on the characteristics of treated leachate and highlight how the digestion of compost leachate is not well clarified yet.…”

“…The above systems showed different behaviors and performances. Indeed, COD removals between 71 and 99.4% were detected while using anaerobic systems, with the AMBR reactors having the highest removal rates reported [36]. Mokhtarani et al [12] found that the COD removal efficiency was independent of organic load rate (OLR) below a value of 6 kg COD /m 3 d, while the COD removal efficiency was significantly reduced above that threshold.…”

Biological treatment of leachate from stabilization of biodegradable municipal solid waste in a sequencing batch biofilm reactor

“…Organic waste, for example, sewage sludge, organic municipal solid waste or green waste, must be stabilized. For this purpose, aerobic stabilization or composting is widely used solution (Roy et al 2018). Both these processes proceed in the same way.…”

Treatment of Water and Wastewater for Reuse and Energy Generation-Emerging Technologies

“…The MBR is usually combined with conventional systems including thermophilic or mesophilic bioprocesses, AOPs, powdered activation carbon to enhance improve the water quality and treatability efficiency [39,40,42,44]. Some of the advantages of MBRs include small foot-print requirement, simple transport configuration and the ability to handle high biomass concentrations [45].…”