Improvement of anaerobic digestion of landfill leachate by using coagulation‐flocculation, Fenton's oxidation and air stripping pretreatments

Abstract

In Tunisia, the anaerobic digestion process is regarded as a new alternative for the treatment of landfill leachate (LFL). Raw LFL contained high amounts of organic matter, high ammonia concentrations and low biodegradability. In order to improve anaerobic conditions and biogas yields, pretreatment using coagulation‐flocculation, Fenton oxidation (FO) and air stripping processes were investigated and compared in terms of biogas production. Air stripping process was optimized using Response Surface Methodology (RSM). Central Composite Design (CCD) was used with three factors. Under optimized conditions, removals of 85% ammonia, 26% chemical oxygen demand (COD) were achieved. Coagulation‐flocculation provided an increase in the effluent biodegradability with 46% of COD reduction. Fenton's oxidation allowed reducing 48% COD, 30% of biological oxygen demand (BOD5). The effect of pretreatments was investigated with the biochemical methane potential (BMP) assay. A comparison of three different pretreatment methods of LFL for biogas production was performed. Air stripping was demonstrated as providing a better biogas yield than other pretreatments which reached 588 mL/g CODint. The best methane yield was obtained using air stripping pretreatment under optimized conditions. It can result in more robust and effective anaerobic digestion. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1041–1049, 2018

Coagulation and oxidation strategies for landfill leachate wastewater

“…In terms of suspended solids, 94% of the VSS was removed in T1, and 90% in T3. The most common biological treatment is anaerobic because it produces less sludge, is excellent for treating young leachates, and generates methane, which is both bene cial for the environment and the economy [13,44].…”

“…Leachate is a liquid by-product of decomposition processes that occurs in the solid waste management process [10,11]. Therefore, leachate has a high concentration of organic substances such humic acids, hydrocarbons, pharmaceuticals, hormones, pesticides, and microplastics in addition to inorganic substances like heavy metals, the majority of which are poisonous and refractory [12][13][14][15][16]. For instance, some leachates have dissolved organic matter concentrations of up to 20,000 mg/L [3,17].…”

Biogas recovery from fresh landfill leachates by using a coupled air stripping-up follow anaerobic sludge blanket (UASB) process

“…The objective was to identify appropriate start-up conditions while using non-diluted leachates. Applied pretreatments were consequently limited to acidity correction, 48h air stripping as recommended by other auteurs [47][48][49], and their combination as illustrated in Table 2. A test containing only inoculum and distilled water was conducted under the same conditions and was used as control pretreatment.…”

Combination of air stripping and biological processes for landfill leachate treatment

“…The experiments were conducted in triplicate at 10 L column with aeration rate of 7 L/min and at room temperature (25 ± 2°C). The pH and reaction time were fixed at 11 and 18 h according to Smaoui et al [30].…”