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The biosorption capacity of untreated olive stones (OS) and olive stones chemically treated (TOS) to remove COD's landfill leachate was investigated in this study. Characterization of the both biosorbents was performed using XRD, SEM, FTIR and 13C NMR techniques. Leachate was taken from Hassi Bounif Sanitary Landfill (HBSL) in Oran (Western Algeria). So, Hassi Bounif Leachate (HBL) exhibited a basic pH between 7.83 and 8.2, high COD level varying from 5,200 to 8,000 mg.L-1, low BOD5/COD ratio from 0.1 to 0.16, and high NH3-N concentrations ranged from 2,300 to 2,800 mg.L-1. Accordingly, this leachate can be classified as an intermediate leachate that is likely to stabilize. Biosorption studies were carried out in a batch system and the effects of contact time, media pH, and biosorbent mass on the removal efficiency of COD were explored. Based on results obtained at pH=11, contact times of 55 and 105 min were achieved for biosorbent masses of 0.1 g for TOS and 0.3 g for OS, respectively, and were found to be the optimal operating conditions for HBL treatment. Thus, the highest COD removal efficiencies of 79.94 and 67.04% were reached for TOS and OS, correspondently. The pseudo-second order model was the best fitted to our experimental data with high regression coefficients (R2 ≥ 0.98). The Langmuir isotherm model adequately represented the COD removal process, with a maximum adsorption capacity of 90.91 mg.g-1 for TOS and 31.25 mg.g-1 for OS at T=50°C and pH=11. The thermodynamic parameters indicated that the biosorption process was feasible, spontaneous, and endothermic. These findings suggested that TOS might be employed as an inexpensive and effective biosorbent for COD removal from stabilized leachate. They can also provide baseline information and design assistance for a leachate treatment plant at the HBSL site, as well as for any sanitary landfill in Algeria. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENT\nPUBLIC INTEREST STATEMENTAdsorption is one of the most efficient ways to eliminate hazardous metals. The study evaluated the effectiveness of banana peel biochar as a cheap adsorbent to remove hazardous metals from landfill leachate. The landfill leachate of 100 mg/L was mixed with banana peel biochar (0.50, 1.50, and 3.00 g each) and placed in a water bath for 15, 30, and 45 min at a constant temperature of 30 °C and 35 °C. The adsorption efficiency of banana peel biochar for nickel in the leachate ranged from 98.76% to 98.96% and chromium ranged from 99.71% to 99.77% at a temperature of 30 °C for 15 mins and 99.07% to 99.27% for Ni and 99.71% to 99.73% for Cr at a temperature of 35 °C for 45 min. Banana peel biochar maximum adsorption capacity of nickel ranged from 1.15 × 10−5 mg/g to 5.27 × 10−6 mg/g, and 1.05 × 10−5 mg/g to 6.76 × 10−6 mg/g for chromium. Adsorbent made from less expensive banana peel can affordably remove nickel and chromium from landfill leachate. To acquire a broad understanding of the adsorbent’s application, more adsorptive research utilizing banana peels as an adsorbent to treat various wastes ought to be conducted.Investigating banana peel biochar as an economical and eco-friendly adsorbent for eliminating toxic metals, particularly nickel and chromium, from landfill leachate is innovative. With high adsorption efficiencies of 99.77% for nickel and 98.96% for chromium, the study showed how banana peel waste can tackle real wastewater treatment and major environmental issues. This study advances knowledge of the uses of biochar in waste management and more investigation into the treatment of a larger spectrum of pollutants, the development of a circular economy, and the improvement of eco-friendly waste treatment techniques using banana peel biochar. Banana peel biochar offers an eco-friendly alternative to synthetic adsorbents and reduces the environmental impact associated with waste disposal.Banana peel biochar offers an eco-friendly alternative to synthetic adsorbents and reduces the environmental impact associated with waste disposal. The adsorption efficiency of nickel and chromium exceeded 98% which indicates a strong affinity of nickel and chromium onto the banana peels biochar surface. Banana peel biochar has high adsorption efficiency for nickel. The removal of nickel from landfill leachate can be accomplished affordably by using inexpensive banana peel biochar as an adsorbent. The dosage of banana peel biochar as well as several experimental variables such as contact time, and temperature favors the adsorption. The banana peel is an efficient and cheap material, which can be used to remove Ni and Cr from wastewater to the permissible limits. [ABSTRACT FROM AUTHOR]

The fate of biobased and biodegradable cellulose-derived plastics in landfills represents an important topic from economic and environmental points of view. Anaerobic digestion is a cost-effective waste-to-energy technology. The behaviour of six polymer types—that is, cellulose (C), cellulose acetate (CA), viscose (V), nanocellulose (NC), acetate textile (AT), and heteropolysaccharide pectin (P)—was studied under anaerobic batch mesophilic conditions in a landfill leachate for 147 days. The cumulative biogas production was as follows: C>V=CA>>AT>>NC=P. Metagenomic analysis revealed notable variations in the proportion of bacterial and archaeal domains with the highest archaeal abundance in the presence of CA (80.2%) and C (78.5%). At the end of digestion, cellulolytic, hydrolytic, and dehydrogenase activities were measured in the intact samples, as well as the liquid and solid fractions, under aerobic and anaerobic conditions. Cellulolytic activity in P was detected only in the pellet, while in NC, activity was mostly in the supernatant under both aerobic and anaerobic conditions. Scanning electron microscopy and confocal scanning laser microscopy showed a defragmentation and degradation of polymeric substrates as well as microbial colonisation. Based on the results, landfill leachate is appropriate for the anaerobic biodegradation of cellulose-derived polymers; however, the process is polymer specific. [ABSTRACT FROM AUTHOR]

Partially Saturated Vertical Constructed Wetlands (PSV-CWs) are novel wastewater treatment systems that work through aerobic and anaerobic conditions that favor the removal of pollutants found in high concentrations, such as rivers contaminated with domestic wastewater and landfill leachate. The objective of the study was to evaluate the efficiency of PSV-CWs using monocultures and polycultures of Typha latifolia and Heliconia psittacorum to treat river waters contaminated with leachates from open dumps and domestic wastewater. Six experimental units of PSV-CWs were used; two were planted with Typha latifolia monoculture, two with Heliconia psittacorum monoculture and two with polycultures of both plants. The results indicated better organic matter and nitrogen removal efficiencies (p < 0.05) in systems with polycultures (TSS:95%, BOD5:83%, COD:89%, TN:82% and NH4+:99%). In general, the whole system showed high average removal efficiencies (TSS:93%, BOD5:79%, COD:85%, TN:79%, NH4+:98% and TP:85%). Regarding vegetation, both species developed better in units with monocultures, being Typha latifolia the one that reached a more remarkable development. However, both species showed high resistance to the contaminated environment. These results showed higher removals than those reported in the literature with conventional Free Flow Vertical Constructed Wetlands (FFV-CWs), so PSV-CWs could be a suitable option to treat this type of effluent. NOVELTY STATEMENT: The research addresses the contamination of water resources in developing countries by landfill leachate and domestic wastewater discharges. It proposes treatment through Partially Saturated Vertical Constructed Wetlands (PSV-CWs), which, despite the limited information available, have been shown to be effective in removing pollutants in effluents with high concentrations. In addition to evaluating PSV-CWs, the study examines the impact of different types of vegetation on pollutant removal efficiency, concluding that PSV-CWs are a promising and viable option for the treatment of these effluents. [ABSTRACT FROM AUTHOR]

In recent years, TiO 2 NPs have attracted great attention among the semiconductors because of stability, commercial availability, and ease of preparation. For this reason, NPs are widely used in wastewater treatment and membrane bioreactor (MBRs) In this study, the effect of titanium dioxide (TiO2) nanoparticle material was investigated on both the landfill leachate (LFL) treatment and membrane fouling performance. The system performance was evaluated for under varying TiO 2 concentrations (50–300 mg/L TiO 2), constant HRT (24 h), and constant backwashing (5 min)-relaxing (0.5 min) in AnMBR. The optimum conditions were determined as 300 mg/L TiO 2 and the corresponding to COD, Color, TOC and TN removal efficiencies were observed as 55 %, 23 %, 22 %, 30 %, respectively. The best membrane performance was observed at 300 mg/L TiO 2 corresponding to membrane fouling rate as 0.01 mbar/min. TiO 2 addition significantly mitigated membrane fouling (75 % decrease) for AnMBR. Bacteroidetes, Firmicutes and Proteobacteria have been observed to be the dominant species in LFL and MBRs. The bacterial species responsible for membrane fouling were determined as Alphaproteobacteria, Sphingobacteria and Flavobacteria. The addition of TiO 2 was determined membrane fouling decreased in AnMBR. As a result of TiO 2 NPs were observed to thin the cake layer and postpone membrane fouling and filtration. [Display omitted] • The best membrane performances were observed at 300 mg TiO 2 /L. • Membrane fouling rate was determined as 0.01 mbar/min. • TiO 2 addition significantly mitigated membrane fouling (75 % decrease). • TiO 2 prevents cake layer formation and/or pore clogging and postpone. • Bacteroidetes, Firmicutes and Proteobacteria have been observed as dominant species. [ABSTRACT FROM AUTHOR]

• A CO 2 combined oxidant method for PRB regeneration is proposed for leachate–contaminated areas near landfill. • CO 2 well-washing technology is used for improving PRBs permeability. • The optimal ratios of oxidants and PRB fillers are proposed to achieve the best regeneration effect. Groundwater contamination near landfills is commonly caused by leachate leakage, and permeable reactive barriers (PRBs) are widely used for groundwater remediation. However, the deactivation and blockage of the reactive medium in PRBs limit their long-term effectiveness. In the current study, a new methodology was proposed for the in situ regeneration of PRB to remediate leachate-contaminated groundwater. CO 2 coupled with oxidants was applied for the dispersion and regeneration of the fillers; by injecting CO 2 to disperse the fillers, the permeability of the PRB was increased and the oxidants could flow evenly into the PRB. The results indicate that the optimum filler proportion was zero-valent iron (ZVI)/zeolites/activated carbon (AC) = 3:8:10 and the optimum oxidant proportion was COD/Na 2 S 2 O 8 /H 2 O 2 /Fe2+ = 1:5:6:5; the oxidation system of Fe2+/H 2 O 2 /S 2 O 8 2− has a high oxidation efficiency and persistence. The average regeneration rate of zeolites was 72.71%, and the average regeneration rate of AC was 68.40%; the permeability of PRB also increased. This technology is effective for the remediation of landfills in China that have large contaminated areas, an uneven pollutant concentration distribution, and a long pollution duration. The purification mode of long-term adsorption and short-time in situ oxidation can be applied to the remediation of long-term high-concentration organically polluted groundwater, where pollution sources are difficult to cut off. [ABSTRACT FROM AUTHOR]

Humic acid (HA) is a typical refractory organic matter, so it is of great significance to investigate its effect on the performance of Anammox granular sludge. When the dosage of HA ≤ 50 mg/L, HA promotes the total nitrogen removal rate (NRR) to 1.45 kg/(m3·day). When HA was between 50 and 100 mg/L, the NRR of Anammox was stable. At this time, the adsorption of HA causes the sludge to gradually turn from red to brown, but the activities of heme and enzymes showed that its capacity was not affected. When HA levels reached 250 mg/L, the NRR dropped to 0.11 kg/(m3·day). Moderate HA levels promoted the release of extracellular polymeric substance (EPS), but excessive HA levels lead to a decrease in EPS concentrations. HA inhibited Anammox activity, which indirectly hindered the transmission of substrate and accumulated substrate toxicity. Although HA promoted the increase of heterotrophic microbial abundance in Anammox system, the microbial diversity decreased gradually. With the increase of HA concentration, the abundance of Candidatus_Brocadia , the main functional microorganism of Anammox system, decreased gradually, while the abundance of Candidatus_Kuenenia increased gradually. [ABSTRACT FROM AUTHOR]

The aim of this study was to systemically evaluate how different pyrolysis temperatures (400, 550, and 700 °C) and particle sizes (1–2 mm and 63–75 µm) were influenced biochar evolution, made from urban pruning waste, during pyrolysis process and to establish their relationships with biochar potential for removal of lead (Pb), cadmium (Cd), and manganese (Mn) from real municipal solid waste landfill leachate. The effects of pH (2–7), contact time (30–300 min) and adsorbent dosage (0.1–5 g L−1) on heavy metals removal were also examined. The results showed that physicochemical properties of biochar were greatly influenced by pyrolysis temperature. Particle size, however, showed little influence on biochar characteristics (p > 0.05). The yield, volatile matter, hydrogen and oxygen contents, and surface functional groups decreased consistently with increasing pyrolysis temperature. An increase in the pH, electrical conductivity, ash, fixed carbon, and specific surface area values was also found. In biochar samples formed at high temperatures (i.e., 550 and 700 °C), Fourier transform infrared spectroscopy-FTIR studies confirmed the increase in aromaticity. Field emission scanning electron microscopy-FESEM images showed differences in the microporous structure and lower size pores at higher temperatures. Biochar pyrolyzed at 700 °C with a particle size of 63–75 µm (i.e., Lv700-63) showed the highest removal efficiency performance. Pb and Cd ions were completely removed (100%) by 0.2 g L−1 Lv700-63 at 7.0 pH and contact times of 120 and 90 min, respectively. The maximum percentage removal of Mn was 86.20% at optimum conditions of 0.2 g L−1 Lv700-63 dosage, 7.0 pH, and 180 min contact time. The findings suggests that the surface complexation, π-electron coordination, and cation exchange were the dominant mechanisms for the Pb, Cd, and Mn removal onto Lv700-63. [ABSTRACT FROM AUTHOR]

Struvite is an eco-friendly fertilizer widely produced from waste streams. Landfill leachate, rich in ammonium-nitrogen (NH4-N), encourages the recovery of NH4-N in the form of struvite. However, the presence of heavy metals, particularly cadmium (Cd) and nickel (Ni), may affect the purity of struvite crystals, thereby hindering its applicability as a fertilizer. While previous studies have examined the effects of various heavy metals on struvite crystallization, the specific impact of Cd and Ni, especially in landfill leachate, remains insufficiently studied. This study aimed to fill this gap by investigating the effect of Cd and Ni on the purity and morphology of struvite crystals obtained from synthetic solutions (Phase 1) and synthetic landfill leachate (Phase 2). Additionally, a kinetics study was conducted to determine the fate of Ni and Cd during struvite crystallization. Batch experiments of struvite precipitation were performed with varying concentrations of Cd and Ni. Aqueous analysis results indicated a minor reduction in NH4-N recovery in both phases when Cd or Ni were present. Furthermore, XRD and SEM analyses of solid samples demonstrated that all crystals were highly pure struvite. The impact of Cd and Ni in Phase 2 was slightly more significant than in Phase 1. The kinetics study suggested that struvite can be safely recovered from landfill leachate contaminated with Cd and Ni. However, further research is needed on actual landfill leachate to fully understand the combined and advanced effects of heavy metals on struvite crystallization. [ABSTRACT FROM AUTHOR]

Partial nitritation (PN) is a novel treatment for nitrogen removal using aerobic ammonium oxidation with reduced oxygen requirements compared to conventional nitrification. This study evaluated the performance of the PN process and the factors influencing nitrogen removal from landfill leachate. During the reactivation of biomass, the results showed 70% ammonium removal, but only 20% total nitrogen removal. Further analysis showed that low nitrite accumulation and high nitrate production promoted the growth of nitrite‐oxidizing bacteria (NOB). The ammonium removal activity after soaking the cultivated biomass in synthetic water and leachate was measured to be 0.57, 0.1, 0.17, and 0.25 g N•g VSS−1•d−1 for synthetic wastewater and leachate soaking for synthetic wastewater, 12 h, 3 days, and 7 days, respectively. The study found abundant ammonium‐oxidizing bacteria (AOB) and NOBs in biomass soaked in synthetic wastewater. However, soaking in leachate promoted AOB growth and inhibited NOB growth making leachate suitable for PN. Practitioner Points: The study found that with a longer leachate‐soaking period for biomass, ammonium removal activity increases, which in turn increases ammonium conversions during the PN process.Ammonium‐oxidizing bacteria (AOB) can acclimate to landfill leachate substrate and grow with a longer soaking period.Nitrite‐oxidizing bacteria (NOB) were inhibited by landfill leachate substrate, which is beneficial for nitrite accumulation.Anabolized DO can convert nitrite to nitrate rapidly, which results in higher nitrate accumulation compared to nitrite accumulation.Hence, the DO level has to be sufficiently low to prevent nitrite oxidation and nitrate accumulation. [ABSTRACT FROM AUTHOR]

Plastic pollution poses a worldwide environmental challenge, affecting wildlife and human health. Assessing the biodegradation capabilities of natural microbiomes in environments contaminated with microplastics is crucial for mitigating the effects of plastic pollution. In this work, we evaluated the potential of landfill leachate (LL) and estuarine sediments (ES) to biodegrade polyethylene (PE), polyethylene terephthalate (PET), and polycaprolactone (PCL), under aerobic, anaerobic, thermophilic, and mesophilic conditions. PCL underwent extensive aerobic biodegradation with LL (99 ± 7%) and ES (78 ± 3%) within 50–60 days. Under anaerobic conditions, LL degraded 87 ± 19% of PCL in 60 days, whereas ES showed minimal biodegradation (3 ± 0.3%). PE and PET showed no notable degradation. Metataxonomics results (16S rRNA sequencing) revealed the presence of highly abundant thermophilic microorganisms assigned to Coprothermobacter sp. (6.8% and 28% relative abundance in anaerobic and aerobic incubations, respectively). Coprothermobacter spp. contain genes encoding two enzymes, an esterase and a thermostable monoacylglycerol lipase, that can potentially catalyze PCL hydrolysis. These results suggest that Coprothermobacter sp. may be pivotal in landfill leachate microbiomes for thermophilic PCL biodegradation across varying conditions. The anaerobic microbial community was dominated by hydrogenotrophic methanogens assigned to Methanothermobacter sp. (21%), pointing at possible syntrophic interactions with Coprothermobacter sp. (a H2-producer) during PCL biodegradation. In the aerobic experiments, fungi dominated the eukaryotic microbial community (e.g., Exophiala (41%), Penicillium (17%), and Mucor (18%)), suggesting that aerobic PCL biodegradation by LL involves collaboration between fungi and bacteria. Our findings bring insights on the microbial communities and microbial interactions mediating plastic biodegradation, offering valuable perspectives for plastic pollution mitigation. [ABSTRACT FROM AUTHOR]

Landfill leachate contains antibiotic resistance genes (ARGs) and microplastics (MPs), making it an important reservoir. However, little research has been conducted on how ARGs are enriched on MPs and how the presence of MPs affects pathogens and ARGs in leachates and soil. MPs possess the capacity to establish unique bacterial populations and assimilate contaminants from their immediate surroundings, generating a potential environment conducive to the growth of disease-causing microorganisms and antibiotic resistance genes (ARGs), thereby exerting selection pressure. Through a comprehensive analysis of scientific literature, we have carried out a practical assessment of this topic. The gathering of pollutants and the formation of dense bacterial communities on microplastics create advantageous circumstances for an increased frequency of ARG transfer and evolution. Additional investigations are necessary to acquire a more profound comprehension of how pathogens and ARGs are enriched, transported, and transferred on microplastics. This research is essential for evaluating the health risks associated with human exposure to these pollutants. [ABSTRACT FROM AUTHOR]

Anaerobic co-digestion (ACoD) has been adjudged as an efficient technology to advance the goal of climate change adaptability and carbon neutrality during waste treatment and bioenergy generation. Prior to digestion integration, an evaluation of the compatibility of the waste streams is critical to enhanced bioenergy output. This study examined the methane potential, microbial ecology, and kinetics during the co-digestion of organic fraction of municipal solid waste (OFMSW), sewage scum (SS), and a blended mixture of 1 part of new and 2 parts of mature leachate (LB) through mesophilic biochemical methane potential (BMP) test. Synergistic interaction within the mixtures increased methane yield by up to 92% (486.7 mL/gVS) over the treatment of OFMSW alone (252.3 mL/gVS). Likewise, the methane yield of LB-containing mixtures was enhanced by 16–41.5% over LB treatment alone (344 mL/gVS). Model estimates by modified Gompertz (MG) and logistic function (LF) were conclusive that the mixtures caused the methane production rate to improve by up to 16% from OFMSW alone and by at least 22% from LB alone. Furthermore, microbial analysis of mixtures revealed the proportion of LB in the mixture had a higher influence on the diversity than OFMSW. Even though acetoclastic Methanosaeta was more dominant, methane production was via a dual methanogenic pathway associated with both acetoclastic Methanosaeta and hydrogenotrophic Methanospirillum. Finally, the results obtained provide an insight on ACoD as a sustainable waste management strategy to enhance bioenergy production and reduce emissions through the recirculation of multiple heterogeneous waste streams into economic use. [ABSTRACT FROM AUTHOR]

In this study, the treatment of landfill leachate in supercritical water conditions with and without catalyst use was investigated. A real waste, namely lathe waste, was used as the catalyst. The experiments were made at a constant 25 MPa pressure, at four reaction temperatures in the range of 450-600°C and four reaction times between 60 and 150 s. Through the experiments, the impacts of reaction temperature, reaction time and the use of lathe waste catalyst on landfill leachate treatment were investigated. The efficiency of the treatment was evaluated in terms of liquid reaction products’ total organic carbon (TOC) and total nitrogen (TN) conversions. As a result, it was seen that elevated reaction temperatures and long residence times favored TOC conversions. On the contrary, greater TN reductions were encountered at lower reaction temperatures. The use of lathe waste was observed to promote the treatment efficiency for all experimental runs. The highest TOC conversion was seen at 600°C and 150 s conditions, which was 57.2% for the noncatalytic treatment. The employment of lathe waste improved this value to 66.9%. As for TN, the highest conversion was encountered at 450°C and at a reaction time of 150 s. At the foresaid reaction conditions, using lathe waste as the catalyst provided 41.9% reduction in the TN content of landfill leachate. [ABSTRACT FROM AUTHOR]

Introduction Landfill leachate, a liquid resulting from waste decomposition, contains nutrients like ammoniacal-N, Na, K, and organic matter. Biological treatments effectively remove degradable organics from young landfill leachate, but aged leachate with recalcitrant organics requires combined physical-chemical and biological methods or advanced technologies, leading to higher treatment costs. Even after treatment, leachate may not meet environmental standards for release. In arid and semi-arid regions with water scarcity and low soil organic matter, leachate application to soil presents a potential solution. Soil’s properties enable it to retain and degrade pollutants while utilizing leachate’s nutrients to enhance fertility and crop growth. However, leachate composition and application rates are critical factors due to potential negative impacts from total nitrogen, salinity, and heavy metals. Alkaline pH in aged leachate reduces heavy metal contamination risk. Detailed leachate characterization before soil application is crucial to prevent environmental and functional problems. This review examines existing research on leachate irrigation’s effects on soil properties and plant nutrition, contributing to sustainable leachate management and agricultural practices in water-limited regions. Additionally, the review explores potential risks associated with leachate irrigation, including soil salinization, heavy metal accumulation, and groundwater contamination. By understanding both the benefits and drawbacks, informed decisions can be made regarding the suitability and implementation of leachate irrigation in specific contexts. Materials and Methods To carry out this study, keywords such as "Landfill leachate", "Composition of landfill leachate" and "Landfill leachate irrigation" were searched in the Web of Science, Google Scholar, ScienceDirect, and SID databases. For these keywords, 205 articles were found from 1989 to 2023. After the screening, quality review, and removal of repetitive and unrelated articles, 110 relevant articles were used. The main criterion for selecting articles was the effects of landfill leachate irrigation on the various properties of soil, and the nutrition of different plant species. The quality of the articles was evaluated through the Scimago Journal Rank (SJR) index, the citation, the Impact Factor, and the source normalized impact per paper (SNIP) index. Results and Discussion Landfill leachate presents a complex environmental challenge due to its potential for both soil contamination and enrichment. Leachate's xenobiotic and heavy metal components can induce soil contamination, altering the natural environment. Studies have documented reduced hydraulic conductivity, increased gas production, and altered microbial communities, ultimately impacting soil productivity. Leachate percolation can also modify physicochemical characteristics, including reduced microbial biomass, phosphorus-fixing capacity, and pH shifts, depending on waste composition. Conversely, research highlights the potential benefits of leachate application in arid and semi-arid regions facing water scarcity and low soil organic matter. Leachate can contribute to the increased organic content, improved soil structure, and regulated pH, enhancing soil fertility and crop productivity. The presence of macro and micro-nutrients such as Fe, Mn, N, P, and Zn further supports leachate's potential as a fertilizer. However, concerns remain regarding inhibitory chemicals in leachate and their potential detrimental effects on plant growth and yield. Studies report instances of leaf injury, reduced yield, and poor survival rates in certain plant species. In contrast, research demonstrates the positive effects of diluted or low-strength leachate application, stimulating plant growth and enhancing yield, particularly for Brassica species and tree species like Acacia confusa, Leucaena leptocephali, and Eucalyptus tortellini. These contradictory findings underscore the intricate interplay of factors influencing leachate irrigation outcomes. Soil characteristics, plant species, leachate source and composition, application methods, and their interactions all play significant roles in determining the success or failure of leachate irrigation. Conclusion Landfill leachate, characterized by its elevated nitrogen and nutrient levels, presents a potential alternative water and fertilizer source for agricultural practices, particularly in arid and semi-arid regions facing water scarcity. However, responsible leachate utilization necessitates a comprehensive approach that balances maximizing benefits with minimizing environmental risks. Prior to agricultural application, detailed leachate characterization is crucial to determine its precise composition and suitability for irrigation. This includes quantifying heavy metal concentrations, salinity levels, and the presence of potentially toxic organic compounds. Concurrent plant selection is equally important, prioritizing species with demonstrated tolerance to leachate constituents. Given the potential for salinity and heavy metal accumulation, continuous application of raw leachate, especially for sensitive crops, should be avoided. Implementing alternating irrigation regimes with conventional water sources can mitigate these risks while providing essential nutrients for plant growth. Monitoring soil health indicators, including pH, organic matter content, and microbial activity, is vital to assess long-term impacts and implement necessary soil amendments. Determining optimal leachate application rates requires a multifaceted approach that considers plant-specific nitrogen requirements, leachate toxicity levels, and soil infiltration capacity. This ensures adequate nutrient supply without exceeding the assimilative capacity of plants and soil, preventing environmental contamination. Further research is needed to investigate the long-term impacts of leachate irrigation on soil health, crop quality, and potential groundwater contamination. Developing standardized guidelines for leachate treatment and application, tailored to specific regional contexts and crop types, is crucial for promoting sustainable and responsible leachate utilization in agriculture. [ABSTRACT FROM AUTHOR]

Disposal of landfill leachate is a critical environmental challenge due to its high pollution content. Effective treatment technologies are essential to mitigate the adverse impacts on groundwater and surrounding ecosystems. This paper employs bibliometric analysis and utilizes CiteSpace software to conduct a visual analysis of the knowledge graph of 959 research articles on "Disposal of Landfill Leachate" from the Web of Science core database for the period 1996-2022. The results indicate that the publication quantity has undergone three stages: the sprouting stage, the stable development stage, and the rapid development stage. In terms of international collaboration, China and the USA play an absolute core role. The journals Waste Management, Journal of Hazardous Materials, and Water Research are ranked among the top 3 publications in the field of landfill leachate treatment. The keyword co-occurrence clustering analysis revealed 7 clusters, including groundwater quality, heavy metals, hydrogeophysics, municipal solid, hydraulic conductivity, geochemical barriers and waste disposal, representing the primary research topics. This paper provides a comprehensive analysis of the research progress and development trends in the field of disposal of landfill leachate. It contributes to a better understanding of the key research areas and offers potential prospects for future investigations to researchers. [ABSTRACT FROM AUTHOR]

A hybrid electrolytic water system was constructed including the anodic electro-oxidation treatment of the leachate from a waste incineration plant as well as the coupled cathodic electrolysis for hydrogen production. Four types of electrolyzers were designed with different flow channels and investigated the effect of different electrolysis parameters on the coupled reactions. The results indicate that the pin-type electrolyzer is superior to the other three electrolyzers in term of the degradation performance and energy consumption. At high current density of 4000 A/m2 and the flow rate of 100 ml/min, the pin-type electrolyzer shows the lowest potential of 6.09 V, the COD removal rate of 98.17% for the leachate and the energy consumption of 200.14 W h. The mass transfer mechanism was further explored under different flow channels and current densities, illustrating that the excellent performance of the pin-type electrolyzer is due to its largest mass transfer area and the most uniform inside flow field distribution. The apparent COD degradation kinetic behaviors were studied, indicating that the maximum degradation rate was 0.033 min-1 at the electric density of 4000A/m2. Such electrocatalytic oxidation of waste leachate coupled with hydrogen production would provide a promising route to construct new hybrid electrolytic water systems. [Display omitted] • Electrooxidation of leachate is successfully coupled with hydrogen production. • The coupled electrolytic water system operates well at 4000-5000A/m2. • COD removal rate is 98.17% in Pin-type electrolyzer at 4000A/m2 and 2h • Flow patterns in different electrolyzer channels are studied using PIV. • The apparent kinetics of leachate electrooxidation degradation were studied. [ABSTRACT FROM AUTHOR]

This study analyzed the impact of leachate from a temporary landfill on soil microbial diversity in Tingo María, Huánuco region, Peru. Three treatments were used: untreated soil (S), addition of stream water (T0), leachate (T1), and leachate treated by coagulation and flocculation (T2), with 828.5 ml/week added in three weekly doses. Soil samples were collected from the Reserved Forest of the Universidad Nacional Agraria de la Selva. Twenty-one randomly distributed soil samples were taken and homogenized for analysis. Soil quality parameters measured included sand, clay, silt, texture, pH, organic matter, nitrogen, phosphorus and potassium. As for microorganisms, viable aerobes, lactobacilli, actinomycetes, fungi, nitrogen-fixing bacteria, and Escherichia coli were quantified using specific culture and counting methods for each of them. To evaluate the impact of the leachate on microbial diversity, equity indices (Shannon and inverse Simpson), dominance indices (complementary Simpson and Berger Parker) and the percentage composition of each microorganism per treatment were used. An ANOVA was performed to estimate differences in microbial diversity, with a Tukey test at a significance level of α = 0.05. The study showed that leachates affect soil microbial diversity, reducing equity and increasing the dominance of certain species such as E. coli. They also alter physicochemical parameters, decreasing organic matter and nitrogen but increasing other elements such as phosphorus and potassium. This could have implications for soil health and functionality. [ABSTRACT FROM AUTHOR]

[Display omitted] • Estimated amount of ∑ 26 PFAS released from landfills (M ̇ SW) was 36.8 g/ha-yr. • 97% and 3% of M ̇ SW was found in leachate and stormwater, respectively. • Less than 1% of M ̇ SW was found in gas condensate and groundwater. • ∑ 8 PFAA-precursors/∑ 26 PFAS was consistent in the leachate released. • PFAS from landfills will be released for an estimated period of over 40 years. Per- and polyfluoroalkyl substances (PFAS) have been found at high levels within landfill environments. To assess PFAS distributions, this study aimed to evaluate PFAS mass flux leached from disposed solid waste and within landfill reservoirs by mass balance analyses for two full-scale operational Florida landfills. PFAS mass flux in different aqueous components within landfills were estimated based on PFAS concentrations and water flow rates. For PFAS concentration, 26 PFAS, including 18 perfluoroalkyl acids (PFAAs) and 8 PFAA-precursors, were measured in samples collected from the landfills or estimated based on previous studies. Flow rates of aqueous components (rainfall, evapotranspiration, runoff, stormwater, groundwater, leakage, gas condensate, and leachate) were evaluated through the Hydrologic Evaluation of Landfill Performance model, water balance, and Darcy's Law. Results showed that the average PFAS mass flux leached from the solid waste standardized by area was estimated as 36.8 g/ha-yr, which was approximately 1 % to 3 % of the total amount of PFAS within the solid waste. The majority of PFAS leached from the solid waste (95 % to 97 %) is captured by the leachate collection system, with other aqueous components representing much smaller fractions (stormwater system at 3 % to 5 %, and gas condensate and groundwater at < 1 %). Also, based on the results, we estimate that PFAS releases will likely occur at least over 40 years. Overall, these results can help prioritize components for waste management and PFAS treatment during the anticipated landfill release periods. [ABSTRACT FROM AUTHOR]

[Display omitted] • PFAS concentrations in aqueous samples were measured at two landfills. • PFAS in municipal solid waste leachate was more variable than MSW ash leachate. • PFAS concentrations were stable within landfills (coefficient of variation < 50 %) • Leachate in uncovered trenches had the highest fluctuations. • PFAS fluctuations associated with alkalinity, total organic carbon, and ammonia. Studies of per- and polyfluoroalkyl substances (PFAS) fluctuations at landfills have focused on municipal solid waste (MSW) leachate. Few studies exist that evaluate fluctuations (defined by the coefficient of variation, CV) in MSW incinerator ash (MSWA) landfill leachate and that evaluate PFAS fluctuations in stormwater, groundwater, and treated liquids on-site. In this study, aqueous landfill samples (leachate, treated leachate, stormwater, gas condensate, ambient groundwater, and effluent from a groundwater remediation system) were collected from a MSW and an MSWA landfill geographically located within close proximity (less than 40 km). The objective of this study was to compare the leachate compositions between these two landfill types and to evaluate temporal variations. Results indicated that the CV of total detected PFAS concentrations in leachate was higher for the MSW landfill (CV = 43 %) compared to the MSWA landfill (CV = 16 %). The total detected PFAS concentration in MSW leachate samples (mean: 9641 ng/L) was higher than in MSWA leachate samples (mean: 2621 ng/L) (p < 0.05). Within a landfill, PFAS concentrations were correlated (r s > 0.6, p < 0.05) with alkalinity, total organic carbon (TOC), and ammonia. Results from the on-site leachate treatment system at the MSW landfill indicated reductions in COD, TOC, and ammonia; however, the ∑ 26 PFAS concentration increased 3 % after the treatment. Overall, results demonstrated that differences between landfill types and fluctuations in PFAS within landfills should be considered when designing landfill leachate collection and treatment systems to remove PFAS. The comparative analysis in this study can provide insights into optimizing leachate management for MSW and MSWA landfills. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three PFAS leached from biochar derived from construction/demolition (CDD) wood. • 5:3 FTCA was reduced by CDD wood biochar in landfill leachate batch leaching. • Low biochar surface area and high matrix organic matter hinder PFAS sorption. • CDD wood biochar not recommended for in-situ landfill leachate PFAS reduction. With regulations for per-and polyfluoroalkyl substances (PFAS) impending, the abundance of these chemicals of emerging concern in municipal solid waste (MSW) landfill leachate increasingly challenges landfill operators to seek on-site leachate pre-treatment options. This two-staged study explores the potential reuse of biochar derived from construction and demolition debris (CDD) wood as an in-situ PFAS sorbent for application within MSW landfill leachate collection systems. Batch leaching tests were first used to examine the feasibility of capturing PFAS from landfill leachate using two sources of CDD-wood-derived biochar. Then, columns were used to test the in-situ sorption capabilities of the same biochars under simulated landfill conditions. All leachates were characterized for pH, chemical oxygen demand, ammonia-nitrogen, and 92 PFAS. Seventeen PFAS were detected in the batch leaching experiment, and nine PFAS were detected in column leachates. In the batch leaching scenario, Biochar 1 achieved a maximum of 29% PFAS reduction compared to controls. Columns containing Biochar 1 generated leachates with PFAS concentrations 50% to 80% higher than those in control columns for the duration of the experiment. Columns containing Biochar 2 generated leachates with PFAS concentrations 44% less than controls in week 1 and similar concentrations in weeks 2, 3, and 4. In this study, PFAS removal from landfill leachate using biochar derived from CDD wood was not significant. Further research on biochar derived from CDD wood is needed before it can be recommended as an in-situ landfill leachate pre-treatment method. [ABSTRACT FROM AUTHOR]

This study investigates landfill leachate treatment using aluminum (Al-Al) and iron (Fe-Fe) electrodes in electrocoagulation (EC). Aluminum experiments revealed COD removal percentages of 22% (pH 7.4) and 20% (pH 6.0), while iron demonstrated higher efficiency at 32% (pH 7.4) and 30% (pH 6.0). Both processes excelled at neutral pH, with Fe-Fe EC displaying superior removal efficiency. To address electrode passivation, external aeration improved COD removal (31% to 61%) under specific conditions (3 V, pH 7.4, 60 min). The EC process established a neutralization mechanism, eliminating the need for further treatment before discharge. External aeration and polarity changes at intervals mitigated passivation, enhancing COD removal (61% to 69%). Voltage testing (1 V, 3 V, 5 V, 7 V) revealed a direct correlation, peaking at 91% efficiency with 5 V. Specific energy consumption was 2.34 kWh g−1, and sludge generation varied with voltage. The combined use of external aeration and polarity shifts resulted in 270 ml of sludge, demonstrating improved efficiency in the EC process. [ABSTRACT FROM AUTHOR]

Nanofiltration concentrated leachate (NFCL) is a high-concentration organic wastewater produced from landfill leachate during the process of membrane advanced treatment, which is more difficult to treat than landfill leachate. In this study, the effect and cost of treating NFCL by flocculation combined with a multistage ozone/bioreactor process based on a field scale are discussed. The results show that the process has a good effect on the removal of organic matter and nitrogen pollutants in NFCL, with removal efficiencies of chemical oxygen demand, ammonia nitrogen, nitrate, and total nitrogen being 96.6%, 90.1%, 38.2%, and 75.8%, respectively. The effluent can meet the discharge standard of China's standard with a direct operating cost of approximately USD 18.48–20.82/m3. This study proved the effectiveness, structural rationality, and economic benefit of the process in a practical engineering application, and provided a certain theoretical basis and engineering reference for the wide application of the process in the treatment of leachate membrane concentrate. [ABSTRACT FROM AUTHOR]

Solid waste landfill (SWL) is known as a major pollution source contaminating air, water sources, and soil environment. The main hazard of SWL is leachate including high organic matter and nutrients. Recently, sulphate radical-based advanced oxidation processes (SR-AOPs) based on persulphate (PS) have been applied as a useful method for removal of chemical oxygen demand (COD) and ammonia from landfill leachate (LL). The removal efficiency of the SR-AOPs depends on effective parameters such as pH, oxidant dosage, catalyst dosage, temperature, reaction time, and so forth. Among SR-AOPs, thermal persulphate oxidation (TPO) seems to be promising for removal of both COD and ammonia; however, the high amount of energy cost is regarded as a major drawback. The drawbacks and future challenges for the use of SR-AOPs for LL have been discussed, and some strategies such as using coupled mechanisms of SR-AOPs have been proposed to tackle the common difficulties. Finally, the performance of SR-AOPs for treatment of LL has been compared with hydroxyl radical processes. [ABSTRACT FROM AUTHOR]

A composite cellulose acetate (CA) carbon-based aluminium hydroxide (CACG) hydrogel membrane was prepared for water purification and real leachate wastewater treatment. The composite CACG hydrogel structure was characterized using scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Initially, the study investigated the efficiency of the composite CACG hydrogel membrane in removing divalent ions such as Cu2+, Pb2+, Mg2+, and Ca2+ at 10 mg/L and 1000 mg/L concentrations from synthetic feed solutions. The results revealed that metal ions removal efficiency was higher at 10 mg/L feed concentration. The composite CACG hydrogel membrane demonstrated high selectivity for Cu2+ and Pb2+ ions, with more than 99% removal from the solution. The performance of the CACG hydrogel was evaluated in four cycles with a constant metal ions removal efficiency of over 98%. These findings suggest composite hydrogel could be a promising adsorbent material for removing metal ions from synthetic water and wastewater. The total suspended solids (TDS) were reduced by 58%. Additionally, the concentrations of arsenic (As3+), lead (Pb2+), zinc (Zn2+), copper (Cu2+), nickel (Ni2+), Manganese (Mn2+), Magnesium (Mg2+), Potassium (K+), Calcium (Ca2+), and Sodium (Na+) saw reductions of 99.9%, 98.3%, 96%, 96%, 99.6%, 93%, 74.75%, 73.6, 60%, and 14.9% respectively. [Display omitted] • CA/AC-aluminium hydroxide hydrogel was prepared and characterized for wastewater treatment. • The hydrogel pure water flux was 30 L/m2h and heavy metals rejection was between 95% and 99%. • The hydrogel rejection of copper was constant at 99% in 4 consecutive filtration cycles. • The order of ions removal was found to be As3+ > Ni2+ > Pb2+ > Zn2+ > Cu2+ > Mn2+> Mg2+ > K+ > Ca2+ > Na+. [ABSTRACT FROM AUTHOR]

[Display omitted] • A CuO modified catalytic membrane integrated with PMS activation was developed. • CuCM/PMS revealed excellent degradation efficiency with alleviated organic fouling. • Refractory organics were degraded to low molecular weight products by CuCM/PMS. • 1O 2 was the dominant ROS responsible for leachate remediation. Membrane concentrated landfill leachate has been characterized by complex component and degradation resistant. In this work, a new catalytic ceramic membrane (CuCM) was developed by in-situ integrating copper oxide in the membrane and used in combination with peroxymonosulfate (PMS) for leachate concentrate treatment. The performance and key factors of the CuCM/PMS system were systematically studied. Results showed that the CuCM/PMS system experienced promising efficiency in the pH range of 3 ∼ 11. The highest COD, TOC, UV 254 and Color removal efficiency achieved by the CuCM-3/PMS system under the conditions of pH = 7.0 and C PMS = 10 mM, which reached up to 63.4%, 50.5%, 75.1% and 90.2%, respectively. The possible mechanism of leachate remediation was proposed and non-free radicals (Cu(Ⅲ), 1O 2) played an important role in the CuCM/PMS system for leachate remediation. The fluorescence spectrum and GC–MS analysis showed that the refractory organics with a high molecular weight in the leachate concentrate were mostly oxidized into small molecules, which also alleviated the membrane fouling. In addition, the slight decrease in COD (7.4%) and TOC (9.7%) after 6 cycles revealed the good catalytic stability and reusability of CuCM-3/PMS. This work provides a feasible strategy for leachate concentrate remediation via a nonradical oxidation process. [ABSTRACT FROM AUTHOR]

The ability of a composite adsorbent composed primarily of various waste materials to adsorb heavy metals, NH3-N, and chemical oxygen demand (COD) from landfill leachate was investigated through batch sorption experiments. The study determined the optimal contact time and adsorbent dosage for the removal of Pb, Zn, Cu, Fe, NH3-N, and COD to be 15, 90, 30, 180, 30, and 30 min, respectively. The corresponding optimum adsorbent dosages were determined to be 5, 30, 5, 15, 5, and 30 g, respectively. The composite adsorbent exhibited high removal efficiencies, achieving the following maximum values: 96.4% for Pb, 92.7% for Zn, 60.3% for Cu, 87.1% for Fe, 75.0% for NH3-N, and 67.5% for COD. Pb and Fe showed the best fit with a Langmuir isotherm model, with corresponding adsorption capacities of 0.0165 and 1.14 mg/g, respectively. For Zn, Cu, NH3-N, and COD, the equilibrium data demonstrated the best fit with an Elovich isotherm model, with adsorption capacities of 0.004, 0.005, 0.016, and 4.29 mg/g, respectively. The kinetic data followed the pseudo-second-order kinetic model. It presented a potential solution for the disposal of the waste from which it was derived. [ABSTRACT FROM AUTHOR]

Without proper treatment, leachate can contaminate adjacent groundwater, soils, and streams, resulting in potential risks to public health, the environment, and surrounding biodiversity. This work aims to treat landfill leachate by coagulation-flocculation and optimize the results using the central composite design in combination with the response surface methodology in the Mohammedia-Benslimane landfill in Morocco. The optimization of the process allowed us to find optimal removal efficiencies of color, polyphenols, and nitrates, which reached 68.8%, 77.5%, and 81.0%, respectively. The optimum conditions in this study were pH 7.66, 9.5 g/L of coagulant dose, 9.1 ml/L of flocculant dose, and 10 min of agitation time. The models obtained for the 3 responses are reliable, reproducible, and well-fitted. By optimizing the leachate treatment at the Mohammedia-Benslimane landfill using coagulation-flocculation and the response surface methodology, our study offers an efficient and reliable approach to address the challenges of landfill leachate treatment. The results obtained from this research have significant implications for liquid waste management, particularly in the context of landfill leachate treatment. [Display omitted] • Leachate characterization. • Optimizing treatment of landfill leachate using coagulation-flocculation. • Color removal. • Polyphenols removal. • Nitrate removal. [ABSTRACT FROM AUTHOR]

The treatment of landfill leachate requires processes that efficiently remove the different contaminants present in this type of liquid waste. To treat this type of waste, a great diversity of biological processes has been used, which take advantage of the capacity to transform the different components of the liquid medium into biomass; however, these processes have limitations due to the intrinsic characteristics of the leachate. In recent years, the integration of biological processes with Advanced Oxidation Processes has been promoted, which would significantly reduce the toxic characteristics of these wastes to comply with the legal conditions to be discharged into the environment without causing damage. In this work, the authors present a review (2015 to 2021) concerning the biological treatment, and Advanced Oxidation Processes (based on ozone, electrochemical processes, and photocatalysis). These processes are analyzed in combination to describe the optimal conditions under which pollutant loads of landfill leachate are reduced. Finally, it is possible to identify that the treatment processes under study are technologies that can be coupled, registering higher efficiencies and lower generation of waste by-products or sludge. [ABSTRACT FROM AUTHOR]

While it is recognized that groundwater contaminant plumes can impact surface waters, there remains little information on the magnitude, spatial extent, and especially temporal variability of the resulting exposure to the variety of aquatic organisms, particularly for stagnant surface waters (e.g., ponds). The present study of a historic landfill plume discharging to a pond investigated contaminant exposure to multiple aquatic zones (endobenthic, epibenthic, pelagic) over approximately 1 year within a temperate climate. Landfill tracers included the artificial sweetener saccharin, ammonium, chloride, and specific conductance. Sampling of pond sediment porewater (upwelling groundwater) and continuous geophysical imaging of the subsurface showed a relatively stable plume footprint covering approximately 26% of the pond, although with spatially varying leachate composition, revealing year‐round exposure to endobenthic (within sediments) organisms. Substantial and variable contaminant exposure to epibenthic organisms within the plume footprint was shown by elevated specific conductance measured directly above the sediment interface. Exposure varied daily at times and increased through winter to values representing undiluted plume groundwater. Exposure to pelagic organisms (overlying water) covered a larger area (~50%) due to in‐pond circulation. The stream outlet concentrations were stable at approximately 10 times dilution for chloride and saccharin, but were substantially less in summer for ammonium due to in‐pond processes. Whereas groundwater contaminants are typically assumed elevated at base flows, the outlet stream contaminant mass discharges to downstream receptors were notably higher in winter than summer, following stream flow patterns. Insights from the present study into the timings and locations of contaminant plume exposure to multiple ecological zones of a pond can provide guidance to contaminated site and aquatic ecosystem managers on improved monitoring, assessment, and remediation protocols. Environ Toxicol Chem 2023;42:1667–1684. © 2023 His Majesty the King in Right of Canada and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada. [ABSTRACT FROM AUTHOR]

• MacCormack scheme based Numerical Model for simulating temperature profile in landfill. • Model Considers waste stratification as new and old as aerobic and anaerobic. • Includes depth Variability in density, moisture content & hydraulic conductivity. • A correlation of 0.8 and 0.73 is obtained in calibration & validation. • Landfill temperature rises at all depths and in all season. Elevated Landfill temperatures have an undesirable effect on landfill cover, stability, slope and leachate migration pattern. Thus, to predict the temperature profile in the landfill a distributed numerical model using MacCormack finite difference method is developed. The developed model considers stratification of the upper and lower layers of the waste as new and old waste by assigning different values of heat generation for aerobic and anaerobic processes. Further, as the new layers of the waste get accumulated over the older layers, the density, moisture content and hydraulic conductivity of the underlying waste layers get modified. The mathematical model utilizes a predictor–corrector approach with a Dirichlet boundary at the surface and no flow condition at the bottom. The developed model is applied to the Gazipur site located in Delhi in India. A correlation coefficient of 0.8 and 0.73 is obtained between the simulated and observed temperatures in calibration and validation respectively. The result shows that the temperature at all the depths and in all the seasons was found to be higher than the atmospheric temperature. The maximum difference of 333 °C was observed in December, and the minimum difference of 22 °Cs was observed in June. The temperature rise is higher in the upper waste layers as it undergoes aerobic degradation. The locus of the maximum temperature gets modified with moisture movement. Since the developed model shows a good agreement with the field observation, it can be used to predict the temperature variation within the landfill under different climatic conditions. [ABSTRACT FROM AUTHOR]

One of the best and most affordable ways to remove harmful metals from water is by adsorption. This study investigated the efficiency of guinea fowl (Numida meleagris) eggshells as a low-cost adsorbent for cadmium (Cd) and nickel (Ni) removal from landfill leachate. In replicas, 100 mL wastewater was added to each of the weighed adsorbent dosages (1 g, 1.5 g, 2 g, 2.5 g, 3.0 g, and 3.5 g) in a flat-bottom flask and agitated for 60 minutes at pH of 7.82 and temperature 24 °C. The adsorption efficacy of cadmium and nickel by guinea fowl eggshells were 90.5% to 96.5% and 96.1% to 99.3%, respectively. The maximum adsorption capacity of cadmium was 4.89 × 10-2 mg/g and an adsorption equilibrium (KL) 22.74 mg/L. The Langmuir isotherm model was better fitted to the results of the experiment than the Freundlich isotherm model. [ABSTRACT FROM AUTHOR]

Landfill leachate is a complex liquid waste, considered a significant problem for the environment. Microalgae are presented as an alternative for the treatment and use of wastewater, thanks to its adaptive capacity, being a viable option for its use in leachates. This contribution presents a bibliometric description of the investigations indexed in the SCOPUS database related to microalgae and leachates from landfills. Based on this, the relevance of treatment with microalgae was identified both in wastewater in general and in leachate, in order to know the progress ratio between the two. 88 articles related to microalgae and leachates were found, with China being the most productive country in terms of number of publications. This study showed that the use of microalgae in leachates is a subject in development and is focused on the treatment of this residue, with limited use and bioproduct production studies. [ABSTRACT FROM AUTHOR]

Landfill leachate has been treated by using an anaerobic–anoxic–oxic (A2/O) system at Datansha Wastewater Treatment Plant in Guangzhou, South China for nearly five years. Through the pilot-scale testing and engineering experiments, the impulse loads of the wastewater treatment systems were successfully reduced. The results showed that the highest removal efficiencies of chemical oxygen demand (COD), ammonium-nitrogen (NH 4 +-N), and total nitrogen (TN) for the combined treatment of domestic wastewater and landfill leachate were achieved under the operating conditions of hydraulic retention time = 11 h, dissolved oxygen = 3 mg/L, mixed liquid return ratio = 200%, and sludge return ratio = 80%. Compared with the data obtained from the previous operating A2/O system, the removal efficiencies of COD, NH 4 +-N, and TN increased by 5.6%, 9.8%, and 5.3%, respectively, under the optimal operating conditions for one year. The average effluent concentrations of BOD 5 , COD, NH4+-N, TN, and total phosphorus were 12.4, 29.9, 2.5, 18.0, and 0.5 mg/L, respectively, and these values could be kept below standard discharge limits in China. [ABSTRACT FROM AUTHOR]

A laboratory-scale granular activated carbon-sequencing batch reactor (GAC-SBR) was used to co-treat stabilized landfill leachate with municipal wastewater. GAC-SBR was studied for the different mixing ratios of leachate and municipal wastewater at different hydraulic retention time (HRT). GAC dose (5, 10, 15 and 20 g/L) was optimized for COD reduction with a contact time of 22 h. GAC-SBR treatment efficiency was assessed on mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), turbidity, chemical oxygen demand (COD), ammonia, nitrate, and phosphate removal. Univariate ANOVA was applied to test the statistical significance of treatment at different leachate:wastewater ratios. Results showed that the increase in GAC concentration led to an increase in the removal of COD and ammonia from stabilized landfill leachate. Adsorption efficiency decreased or remained constant after 15 g/L GAC. GAC-SBR was efficient in removing COD (83%) and nutrients (80–90%) from stabilized landfill leachate at 10 d HRT. Univariate analysis of variance (ANOVA) highlighted that there was a statistically significant difference in the treatments for the mixing ratio tested. GAC-SBR results showed that treatment efficiency was dependent on landfill leachate concentration and hydraulic retention time (HRT). Coupled treatment tested exhibited a high potential for co-treatment of leachate and municipal wastewater. However, the effluent after treatment could not achieve a complete or very high level of COD, nutrients and turbidity removal which necessitates the incorporation of physico-chemical processes such as coagulation, electrocoagulation, membrane filtration etc. as post-treatment options. Further studies in this direction along with exploring the longevity of GAC in SBR would provide useful information for effective landfill leachate treatment. [ABSTRACT FROM AUTHOR]

This article provides an analytical model to determine the suitable location of pumping well located between two polluted parallel sources. The first source is assumed to be a polluted river, while the second one is an arbitrary contaminant source such as landfill leachate site or wastewater. The location of the well is specified so that it gets the highest amount of river water that satisfies water quality requirements. To validate the model results, a numerical simulation is conducted using MODFLOW to calculate the concentration of contaminants at various locations determined by the proposed analytical model. The results confirmed the suitability of the analytical model to determine the location of pumping well. Additionally, it is found that any increase in pumping time, pumping rate or initial contaminant concentration increases the distance between river and well. [ABSTRACT FROM AUTHOR]

Landfill leachate that primary and/or secondary technologies have treated needs to be subjected to further purification to meet local discharge limits due to its heavy macro and micro-contaminant load. In this sense, advanced oxidation process (AOP) and membrane-based technologies (i.e., nanofiltration [NF] and reverse osmosis [RO]) are commonly employed as polishing steps to meet legislation requirements. However, membrane-based techniques do not destroy pollutants but produce concentrated streams that must be managed. AOPs can generate sludge and by-products of higher toxicity than their precursors in raw leachate. In this context, this study reviews the ecotoxicological risks and pollution impacts of landfill leachate (1), identifies the weakness of the current leachate ecotoxicological studies to provide recommendations for future investigations (2), outlines the relevance of membrane-based and advanced oxidation techniques to manage landfill leachate (3), and proposes integrated treatment options for landfill leachate purification (4). Different combined methods to ensure proper wastewater purification characterize the leachate treatment chain. Biological processes followed by RO have showcased a significant trend within the leachate treatment chain. These systems operate with macro and micro-pollutants removal higher than 90%. On the other hand, managing treatment's by-products is challenging. An ozone-based technique could be integrated downstream to promote membrane concentrate and sludge mineralization. Combining membrane and ozone-based processes is promising to overcome concentrate management and toxicity issues. However, high-energy demand might render this kind of treatment configuration unfeasible, especially in small and middle-size landfills from remote sites. In this sense, landfill gas utilization and developing support energy systems based on renewables are critical in closing the leachate treatment loop. [Display omitted] [ABSTRACT FROM AUTHOR]

The present study investigated the acute toxic effects caused by the main pollutants found in landfill leachates: total ammonia nitrogen (TAN), alkalinity, and humic substances (HS) for the test organisms Vibrio fischeri , Danio rerio , Daphnia similis , and Artemia sp. The leachates were obtained from two Brazilian landfills with different ages and operating modes. Air stripping and membrane filtration treatability experiments were performed to remove pollutants from the leachate. The results showed high toxicity of the raw leachate from both landfills for the studied organisms. In the individual treatments, air stripping achieved TAN and alkalinity removal efficiencies > 99%, and the membrane filtration treatment achieved HS removal efficiencies > 98%. Compared to the individual treatments, the combination of treatments resulted in the most significant reductions in leachate toxicity from both landfills for all test organisms studied. The principal component analysis showed a strong correlation between COD or HS parameters and the toxicity of V. fischeri and strong correlations between TAN and the toxicity of D. rerio, D. similis , and Artemia sp. Finally, this study highlights the application of a treatment route to remove acute toxicity from complex effluents, such as landfill leachate, to avoid potential environmental hazards to the aquatic ecosystem. [ABSTRACT FROM AUTHOR]

[Display omitted] Per- and polyfluoroalkyl substances (PFAS) are present in landfill leachate, posing potential challenges to leachate disposal and treatment. This work represents the first study of a thin-water-film nonthermal plasma reactor for PFAS degradation in landfill leachate. Of the 30 PFAS measured in three raw leachates, 21 were above the detection limits. The removal percentage depended on the category of PFAS. For example, perfluorooctanoic acid PFOA (C8) had the highest removal percentage (77% as an average of the three leachates) of the perfluoroalkyl carboxylic acids (PFCAs) category. The removal percentage decreased when the carbon number increased from 8 to 11 and decreased from 8 to 4. The effects of various landfill leachate components, including sodium chloride, acetate, humic acids, pH, and surfactants, had no or minor impacts (<30%) on PFOA mineralization in synthetic samples. This might be explained by the plasma-generation and PFAS-degradation mainly occurring at the gas/liquid interface. Shorter-chain PFCAs were produced as intermediates of PFOA degradation, and shorter-chain PFCAs and perfluorosulfonic acids (PFSAs) were produced as intermediates of perfluorooctanesulfonic acid (PFOS). The concentrations of the intermediates decreased with decreasing carbon number, suggesting a stepwise removal of difluoromethylene (CF 2) in the degradation pathway. Potential PFAS species in the raw and treated leachates were identified at the molecular level through non-targeted Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The intermediates did not show accurate toxicity per Microtox bioassay. [ABSTRACT FROM AUTHOR]

One of the best and most affordable ways to remove harmful metals from water is by adsorption. This study investigated the efficiency of guinea fowl (Numida meleagris) eggshells as a low-cost adsorbent for cadmium (Cd) and nickel (Ni) removal from landfill leachate. In replicas, 100 mL wastewater was added to each of the weighed adsorbent dosages (1 g, 1.5 g, 2 g, 2.5 g, 3.0 g, and 3.5 g) in a flat-bottom flask and agitated for 60 minutes at pH of 7.82 and temperature 24 °C. The adsorption efficacy of cadmium and nickel by guinea fowl eggshells were 90.5% to 96.5% and 96.1% to 99.3%, respectively. The maximum adsorption capacity of cadmium was 4.89 × 10-2 mg/g and an adsorption equilibrium (KL) 22.74 mg/L. The Langmuir isotherm model was better fitted to the results of the experiment than the Freundlich isotherm model. [ABSTRACT FROM AUTHOR]

The present study investigates the effects of landfill leachate pretreatment by coagulation-flocculation (C/F) on the performance of nanofiltration (NF) and reverse osmosis (RO) membranes by comparing permeate flux, fouling resistance, and leachate quality. Pretreated leachates were produced by applying the C/F with ferric chloride (FeCl 3) and alum sulfate (Al 2 (SO 4) 3), named P1 and P2 leachates. Raw leachate (RL), P1, and P2 samples were treated using five different polymeric membranes termed NP030, NP010, XN45, BW30, and X201. The C/F pretreatment with FeCl 3 or Al 2 (SO 4) 3 increased XN45's permeate flux by more than 80%. In this case, fouling median resistance values were 2.13e+ 08, 0.96e+ 08, and 1.02e+ 08 m−1 for RL, P1, and P2, respectively. Kruskal-Wallis test showed a significant difference between RL and pretreated leachate groups (p-value < 0.05). No significant difference between P1 and P2 was identified by the Dwass-Steel-Critchlow-Fligner test run for pairwise comparisons. These results indicate that the leachate pretreatment reduced membrane fouling by more than 50%, independently of the coagulant employed. Although higher removals of organic contaminants were, on average, obtained by membrane treatment for RL than for P1 and P2 samples, membranes that operated for RL treatment presented the worst performance in terms of permeate flux and fouling resistance. Therefore, NF and RO processes are not advisable as a single step in a landfill leachate treatment train, and a pretreatment step is recommended. This research makes a major contribution to the field by providing quantitative data for the conceptual premise that leachate pretreatments mitigate membrane fouling. Our findings help elucidate pretreatment effects on membrane performance and determine the preferable leachate treatment layout. [Display omitted] [ABSTRACT FROM AUTHOR]

This study aimed at sustainable treatment of municipal landfill leachate (MLL) along with resource recovery by integrating acidogenesis and bioelectrogenesis. Initially, during acidogenic fermentation, more than 60 % of MLL COD was converted to biohydrogen (0.23 L/g COD load) and volatile fatty acids (VFAs; 56.15 g COD/L). Acetic (25.09 g COD/L), propionic (1.27 g COD/L), and butyric acid (29.77 g COD/L) made up the majority of VFAs. To increase MLL's further treatment, the left-over COD in the acidogenic effluent was introduced into bio-electrochemical treatment system. Three differently configured bio-electrochemical treatment systems (BET 1 , BET 2 , and BET 3) were evaluated varying their anode composition. BET 1 was operated with a capacitive designed PANi/CNT composite electrode, while BET 2 was operated with PANi-SSM and BET 3 with a graphite electrode. The modified composite electrode in BET 1 played a significant role in leachate treatment (COD removal, 71.21 %) displaying a power density of 35 mW/m2. Apart from higher removal of ammoniacal nitrogen, sulfates and phosphates, the composite electrodes in the BET 1 resulted in improved bioelectrogenic activity and capacity of electrons migration between electrode and biocatalyst. Additionally, the modified anode showed higher redox peak currents, lower charge transfer resistance, and ohmic losses. [Display omitted] [ABSTRACT FROM AUTHOR]

Microalgal cultivation for biodiesel and feed requires recycled nutrient resources for a sustainable long‐term operation. Whey permeate (WP) from dairy processing contains high organic load (lactose, oils, and proteins) and nitrogen (resources tested for microalgal cultivation) and organic phosphorus (P) that has not yet been tested as a P source for microalgal cultivation. We explored the potential of green algae strains (brackish) and polyculture (freshwater) in exploiting P from WP added to a medium based on either seawater (7 psu) or landfill leachate. Both strains showed a capacity of using organic P in WP with equal growth rates (0.94–1.12 d−1) compared with chemical phosphate treatments (0.88–1.07 d−1). The polyculture had comparable growth rate (0.25–0.57 d−1) and biomass yield (152.1–357.5 mg L−1) and similar or higher nutrient removal rate in the leachate–WP medium (1.3–6.4 mg L−1 day−1 nitrogen, 0.2–1.1 mg L−1 day−1 P) compared with the leachate–chemical phosphate medium (1.2–4.7 mg L−1 day−1 nitrogen, 0.3–1.4 mg L−1 day−1 P). This study showed that WP is a suitable P source for microalgal cultivation over a range of salinities. To date, this is the first study demonstrating that raw WP can replace mineral P fertilizer for algal cultivation. Practitioners Points: Whey permeate is a comparable phosphorus source to standard fertilizers used in algal cultivation.Green algae removed phosphorus effectively from whey permeate.Microalgal cultivation is a good approach for treatment of whey permeate in combination with a nitrogen‐rich wastewater. [ABSTRACT FROM AUTHOR]

Landfill leachate is a major hazard for the surrounding ambience as it detrimentally contaminates the soil and groundwater. In the present study, sulfate radical based advanced oxidation process (SR-AOP) was adopted for the treatment of stabilized/mature landfill leachate (SLL) using pyrite (FeS 2) as a heterogeneous catalyst. The FeS 2 catalyst was characterized using XRD, FT-IR, SEM and EDX spectroscopy techniques to evaluate its structural, functional groups, morphological features, and chemical composition, respectively. The effect of various operating parameters on SR-AOP such as initial pH, FeS 2 dosage, Na 2 S 2 O 8 concentration, and temperature on COD and TOC removal was also studied. The FeS 2 (1000 mg/L), Na 2 S 2 O 8 (1000 mg/L) concentrations at pH 8.8 were found optimal, and COD and TOC removals were found as 78.5% and 74.2%, respectively. After the treatment of SR-AOP, BOD 5,20 /COD ratio of landfill leachate was improved from 0.023 to 0.41. Scavenging tests revealed that the primary oxidative species in SR-AOP are •OH and SO 4 •-; however, SO 4 •- plays a major role while •OH is also involved in the process. Intriguingly, no significant change in the catalytic efficiency and characteristic nature of FeS 2 was observed even after four sequential treatments of the same FeS 2 catalyst. [Display omitted] [ABSTRACT FROM AUTHOR]

Aerobic granular sludge (AGS) systems treating effluents with a C:N:P ratio similar to real old landfill leachate were evaluated on simultaneous C, N and P removals, and to reduce the main problems encountered, such as nitrite accumulation, biomass loss, and granule disintegration. Therefore, six sequential batch reactors (SBR) were operated with different anaerobic (A), anoxic (An), and aerobic (O) configurations: A/O (R1 and R2), O/An with conventional feeding and well-defined anoxic phase (R3), O/An with step-feeding and well-defined anoxic phase (R4), and O/An (R5 and R6). The O/An with step-feeding reactor (R4) had the highest biomass retention/settleability (SVI 30 < 50 mL/g), the best nitrification rates (99%), and chemical oxygen demand (COD) (97%), total nitrogen (91%) and total phosphorous (55%) removals. Furthermore, there was no nitrite accumulation, and granules' disintegration was insignificant. The most abundant phylum in the reactors O/An was Planctomycetota, composed mainly of organisms from the Pirellulaceae and Legionellaceae families. In these reactors, the abundance of phosphorus-accumulating organisms (PAOs) and denitrifying bacteria were similar, while the abundance of glycogen-accumulating organisms was much higher than PAOs. Therefore, the type of cycle directly influences performance, granule characteristics, and system stability, being important for future investigations applying the AGS technology to leachate treatment. [Display omitted] • Effect of cycle type was studied in aerobic granular sludge (AGS) systems. • Oxic (O)/anoxic (An)-type reactor with a well-defined An phase was the best cycle configuration. • The highest COD, TN, and P removals were achieved at the O/An cycle with step-feeding. • The intercalation of the feast/famine and anoxic periods minimized nitrite accumulation. • Planctomycetota was the most abundant phylum in the reactors with a well-defined anoxic phase and step-feeding. [ABSTRACT FROM AUTHOR]

Partial nitrification‐anammox (PN/A) is an energy‐efficient technology for nitrogen removal in landfill leachate treatment. Numerous studies have reported successful implementation of the PN/A process and its stable operation under laboratory conditions. One of the primary challenges in PN/A engineering applications is the mass of the seed sludge required for start‐up. This study examined the PN/A using a sequence batch reactor (SBR) inoculating a common mixture to treat landfill leachate. After 70 days of operation, the system successfully realized a one‐stage PN/A process and maintained a stable ammonium NH4+$$ \left({NH}_4^{+}\right) $$ removal efficiency of 97.65% ± 1%, where the effluent of NH4+$$ {NH}_4^{+} $$ and nitrate (NO3−$$ {NO}_3^{-} $$) were less than 4 ± 1.5 mg L−1 and 10 mg L−1. In addition, the relative abundances of Ca. Kuenenia and Ca. Brocadia, which are typical anaerobic ammonia‐oxidizing bacteria (AnAOB), increased from 0.08% to 3.99% (70 days) and 0.01% to 0.45%, respectively. The relative abundances of ammonia‐oxidizing bacteria (AOB) Nitrosomonas and Nitrosospira increased from 0.9% to 2.89% and 0.007% to 0.1% (70 days), respectively. Both AnAOB and AOB are important niches of the system. Practitioner Points: The research realized PN/A rapidly by inoculating common mixture sludge.The experiment successfully enriched AnAOB from 0.09% to 3.89% within 70 days.The article revealing the ecological roles of AOB and AnAOB in the landfill leachate treatment. [ABSTRACT FROM AUTHOR]

Landfill leachate (LFL) treatment is a severe challenge due to its highly viscous nature and various complex pollutants. Leachate comprises various toxic pollutants, including inorganic macro/nano components, xenobiotics, dissolved organic matter, heavy metals, and microorganisms responsible for severe environmental pollution. Various treatment procedures are available to achieve better effluent quality levels; however, most of these treatments are nondestructive, so pollutants are merely transported from one phase to another, resulting in secondary contamination. Anaerobic digestion is a promising bioconversion technology for treating leachate while producing renewable, cleaner energy. Because of its high toxicity and low biodegradability, biological approaches necessitate employing other techniques to complement and support the primary process. In this regard, pretreatment technologies have recently attracted researchers' interest in addressing leachate treatment concerns through anaerobic digestion. This review summarizes various LFL pretreatment methods, such as electrochemical, ultrasonic, alkaline, coagulation, nanofiltration, air stripping, adsorption, and photocatalysis, before the anaerobic digestion of leachate. The pretreatment could assist in converting biogas (carbon dioxide to methane) and residual volatile fatty acids to valuable chemicals and fuels and even straight to power generation. However, the selection of pretreatment is a vital step. The techno-economic analysis also suggested the high economic feasibility of integrated-anaerobic digestion. Therefore, with the incorporation of pretreatment and anaerobic digestion, the process could have high economic viability attributed to bioenergy production and cost savings through sustainable leachate management options. [ABSTRACT FROM AUTHOR]

Catalytic oxidation pretreatment is a significant focus in the field of membrane fouling control; however, traditional catalytic materials are plagued by limitations in catalytic sites and challenges in recovery. In this study, a novel catalyst, B-doped NiFe 2 O x , was prepared with magnetic recovery capabilities and abundant oxygen vacancies to address landfill leachate treatment and mitigate membrane fouling. The results demonstrated the efficient activation of persulfate (PS) by the catalytic sites on B-NiFe 2 O x , which significantly degraded the complex organic pollutants like conjugated double bonds and aromatic compounds in landfill leachate. A large amount of humic acid and soluble microbial products in the landfill leachate were efficiently degraded upon contact with sulfate and hydroxyl radicals produced by B-NiFe 2 O x /PS, thereby resulting in achieving a chemical oxygen demand removal efficiency of up to 72 % and more than a twofold enhancement in filtration flux. Moreover, the characteristics of the fouled layer reveal that the B-NiFe 2 O x /PS system facilitated the formation of a porous cake layer, maximizing the retention of functional groups on the NF270 membrane surface. Notably, a minor presence of B-NiFe 2 O x is uniformly distributed within the cake layer, indicating the in-situ occurrence of weak catalytic oxidation reactions. This study provides an effective and innovative approach utilizing catalytic oxidation for membrane fouling control. [Display omitted] • B-NiFe 2 O x /PS was used for the first time to mitigate membrane fouling. • The production of·OH and·SO 4 2- were the main oxidation and antifouling mechanisms. • B-NiFe 2 O x /PS reduced the membrane foulants and formed the loose cake layer. • Abundant humic substances and SMPs were efficiently degraded by B-NiFe 2 O x /PS. • A small amount of B-NiFe 2 O x participated in the in-situ catalytic oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microbial diversity and composition changed during process upgrade. • Key biomarkers like Nitrosomonas were identified. • Process upgrade and floc size affect microbial community assembly. • Upgrade led to denser, more homogeneous microbial networks with closer interactions. • A deep learning model was developed for predicting nitrogen removal efficiency. Upgrading processes to reduce biodegradable organic substance addition is crucial for treating landfill leachate with high pollutant concentrations, aiding carbon emission reduction. Aggregate size in activated sludge processes impacts pollutant removal and sludge/water separation. This study investigated microbial community succession and driving mechanisms in different floc-size aggregates during nitrogen removal progress upgrade from conventional to partial nitrification–denitrification in a full-scale landfill leachate treatment plant (LLTP) using 16S rRNA gene sequencing. The upgrade and floc sizes significantly influenced microbial diversity and composition. After upgrading, ammonia-oxidizing bacteria were enriched while nitrite-oxidizing bacteria suppressed in small flocs with homogeneity and high mass transfer efficiency. Larger flocs enriched Defluviicoccus , Thauera , and Truepera , while smaller flocs enriched Nitrosomonas , suggesting their potential as biomarkers. Multi-network analyses revealed microbial interactions. A deep learning model with convolutional neural networks predicted nitrogen removal efficiency. These findings guide optimizing LLTP processes and understanding microbial community dynamics based on floc size. [ABSTRACT FROM AUTHOR]