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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]

Landfills are a known source of PFAS pollution. Many have environmental permits allowing the discharge of treated leachate to controlled waters. In this article we compared leachate data for 17 PFAS from 17 different landfill sites across the UK. The results show that the landfill leachate treatment process (designed to improve water quality) is generating the banned PFAS; PFOA and PFOS. Approximately 80% of locations tested showed an increase in PFOS, with an increase of 1,335% in one sample. The highest concentrations of PFOS and PFOA in treated leachate were 2,460 ng L−1 and 26,900 ng L−1, respectively. When compared against the environmental quality standard of 0.65 ng L−1 for PFOS this leachate could pose a significant concern. Landfill leachate treatment has proven effective for a wide range of different pollutants, but this research shows in several instances that it is not appropriate for PFAS remediation. [ABSTRACT FROM AUTHOR]

Landfills are a known source of PFAS pollution. Many have environmental permits allowing the discharge of treated leachate to controlled waters. In this article we compared leachate data for 17 PFAS from 17 different landfill sites across the UK. The results show that the landfill leachate treatment process (designed to improve water quality) is generating the banned PFAS; PFOA and PFOS. Approximately 80% of locations tested showed an increase in PFOS, with an increase of 1,335% in one sample. The highest concentrations of PFOS and PFOA in treated leachate were 2,460 ng L−1 and 26,900 ng L−1, respectively. When compared against the environmental quality standard of 0.65 ng L−1 for PFOS this leachate could pose a significant concern. Landfill leachate treatment has proven effective for a wide range of different pollutants, but this research shows in several instances that it is not appropriate for PFAS remediation. [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]

Leachate generated from landfills contains many toxic contaminants, such as dissolved organics, inorganic salts, ammonia, and heavy metals, which impact the surrounding environmental systems. This study characterized the AL-Mufarrihat Sanitary Landfill (MSL) leachate in Al-Medinah Al-Munawwarh (MM) province, Saudi Arabia, by analyzing important physicochemical parameters. Phytotoxicity was assessed using various higher plant bioassays, namely, cucumber (Cucumis sativus L.), tomato (Lycopersicum esculentum L.), cabbage (Brassica oleracea var. capitata L.), and corn (Zea mays L.). The effective concentration of seed germination represented by EC50 was calculated using a USEPA computer program based on Finney's Probit analysis method. Selected phytotoxicity test endpoint parameters, namely relative seed germination (RSG), relative root elongation (RRE), and germination index (GI) were determined. The tested leachate exhibited low concentrations of heavy metals, whereas high levels of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) were recorded. The mean EC50 values for MSL leachate exposed to B. oleracea, L. esculentum, C. sativus, and Z. mays were 2.66%, 3.12%, 4.27%, and 5.22%, respectively. These values indicate that B. oleracea was the most sensitive bioassay, whereas Z. mays was the least sensitive. All tested bioassays showed severe phytotoxic responses to the exposed higher leachate concentrations, represented by complete inhibition for RSG, RRE, and GI. Lower leachate concentrations exhibited stimulatory effects on RSG, whereas RRE and GI were hindered, even at these lower concentrations. The results revealed that although RSG and RRE were effective and promising parameters in phytotoxicity evaluation, GI was the most responsive parameter for phytotoxicity assessment. The high levels of organic and inorganic compounds in the leachate are likely the primary cause of the phytotoxicity observed in the bioassays. The results of this study highlight the pollution potential of landfill leachate in Saudi Arabia and will furnish supplementary reference information for hazard assessment and future leachate management. [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]

A Gram-stain-negative, facultative anaerobe, rod-shaped strain JX-1T was isolated from UASB sludge treating landfill leachate in Wuhan, China. The isolate is capable of growing under conditions of pH 6.0–11.0 (optimum, pH 7.0–8.0), temperature 4–42 ℃ (optimum, 20–30 ℃), 0–8.0% (w/v) NaCl (optimum, 5.0%), and ammonia nitrogen concentration of 200–5000 mg/L (optimum, 500 mg/L) on LB plates. The microorganism can utilize malic acid, D-galactose, L-rhamnose, inosine, and L-glutamic acid as carbon sources, but does not reduce nitrates and nitrites. The major fatty acids are C18:1ω7c/C18:1ω6c, iso-C15:0, and anteiso-C15:0. The respiratory quinones are Q9 (91.92%) and Q8 (8.08%). Polar lipids include aminolipid, aminophospholipid, diphosphatidylglycerol, glycolipid, phosphatidylethanolamine, phosphatidylglycerol, and phospholipid. Compared with other strains, strain JX-1T and Denitrificimonas caeni HY-14T have the highest values in terms of 16S rRNA gene sequence similarity (96.79%), average nucleotide identity (ANI; 76.06%), and average amino acid identity (AAI; 78.89%). Its digital DNA-DNA hybridization (dDDH) result is 20.3%. The genome of strain JX-1T, with a size of 2.78 Mb and 46.12 mol% G + C content, lacks genes for denitrification and dissimilatory nitrate reduction to ammonium (DNRA), but contains genes for ectoine synthesis as a secondary metabolite. The results of this polyphasic study allow genotypic and phenotypic differentiation of the analysed strain from the closest related species and confirm that the strain represents a novel species within the genus Denitrificimonas, for which the name Denitrificimonas halotolerans sp. nov. is proposed with JX-1T (= MCCC 1K08958T = KCTC 8395T) as the type strain. [ABSTRACT FROM AUTHOR]

In this work, biochars were used as adsorbents to remove Cu, Cd, and Zn ions in a real stabilized leachate from a controlled landfill. Oak fruit shells biochar (OFSBC) and date palm fibers biochar (DPFBC) were obtained by pyrolysis of oak fruit shells and date palm fibers at 700 °C and 400 °C, respectively. OFSBC and DPFBC showed well-developed structures and high specific surface areas (520.16 m2/g and 470.46 m2/g, respectively). Equilibrium adsorption of heavy metal ions on DPFBC and OFSBC occurred after 4 h and 2 h of stirring. The removal efficiencies of Cu, Cd, and Zn ions were 97.01%, 94.40%, and 80.59% with DPFBC and 90.10%, 88.33%, and 76.16% using OFSBC, respectively. The Avrami fractional order model was appropriate for describing kinetic adsorption. Increasing the dose of adsorbent improves heavy metal ion retention. Thermodynamic tests have proven the spontaneous and endothermic adsorption of these heavy metals. The electrostatic attraction, ion exchange, complexation, metal-π bending, and surface precipitation and pore filling were regarded as the most predominant heavy metal retention mechanisms from the landfill leachate onto the biochar surface. Separately, the DPFBC showed the best performance than OFSBC regarding the improvement of leachate quality. Chemical oxygen demand (COD), biological oxygen demand (BOD5), ammoniacal nitrogen (NH3-N), and phosphorus (P) were respectively removed at an efficiency of 53.57%, 29.17%, 36.07%, and 37.5%, respectively. Thus, the results allow highlighting that the adsorption on DPFBC and OFSBC can be an effective alternative in the practice of landfill leachate treatment. [ABSTRACT FROM AUTHOR]

Municipal solid waste (MSW) management is a significant challenge in Jordan, particularly regarding landfill leachate (LL). Al-Ghabawi landfill, the country's largest, lacks proper leachate treatment, with the current practice being limited to evaporation in open ponds, an environmentally unacceptable method. This study dealt with the coagulation process for treating LL produced from Al-Ghabawi landfills by using alum and moringa seeds as coagulants. The results showed that the optimum pH for the coagulation process was 5.5. The optimal dosages were 800 mg/L for moringa oleifera and 400 mg/L for alum (high dose), and 80 mg/L for moringa oleifera and 40 mg/L for alum (low dose). The use of moringa oleifera and alum together yielded the best removal rates for turbidity (48.9%), total suspended solids (TSS) (41.21%), total dissolved solids (TDS) (17.9%), and Mn (73.7%). Pb and Cr, however, exhibited lower removal rates, with the best achieved by using moringa seeds and alum together (42.8% and 46.58%, respectively). Notably, moringa oleifera seeds alone as a coagulant outperformed alum in removing COD (91.57%) and BOD (85.71%), indicating that moringa oleifera is a more effective option for increasing the biodegradability of the leachate, as evidenced by the increased BOD5/COD ratios, from 0.5159 to 0.875 and 1.206 for high and low doses, respectively. These findings suggest that the coagulation process can be significantly improved by utilizing moringa oleifera seeds, a natural and sustainable coagulant, in combination with alum for the treatment of Al-Ghabawi LL. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrothermal carbonization (HTC) emerges as a promising avenue for converting food waste into valuable resources while addressing environmental concerns. This study investigated the optimization of HTC parameters, utilizing landfill leachate as a sustainable moisture source and exploring methane recovery from process water. Employing the response surface methodology (RSM) and artificial neural networks (ANN), the influence of key process variables on HTC efficiency was meticulously analyzed. Notably, the superior predictive capability of ANN over RSM was demonstrated, with a lower mean-squared error and a higher correlation coefficient. The identified optimal HTC conditions were 193°C for 175 min at a solid/liquid ratio of 0.2; under these conditions, RSM and ANN predicted mass yields of 66.37 ± 1.15% and 65.68 ± 0.11%, respectively. Furthermore, under these conditions, process water exhibited a remarkable biomethane production rate of approximately 283.11 ± 13.5 mL/g COD, fitting well with the modified Gompertz model. This study advances HTC optimization strategies and underscores the potential of integrating landfill leachate and methane recovery into food waste valorization processes, thereby paving the way for sustainable resource management practices. [ABSTRACT FROM AUTHOR]

The management of landfill leachate presents a significant environmental challenge, necessitating a comprehensive and dynamic treatment approach. This comprehensive review delves into the critical issue of landfill leachate treatment, exploring its environmental impact, treatment technologies, regulatory frameworks, and the path towards sustainable management practices. This review explores the complexities of landfill leachate, emphasizing the need for sustainable waste management practices to safeguard environmental health. Our analysis highlights the evolution of conventional and advanced treatment technologies designed to mitigate these risks, focusing on membrane technologies, advanced oxidation processes, and the promising potential of emerging techniques such as adsorption and biological nutrient removal. These technologies are evaluated for their efficiency, cost implications, and sustainability impacts, underscoring the challenges and opportunities within the current landscape of leachate treatment. The review aims to provide insights into designing efficient and effective treatment systems through a detailed analysis of conventional and advanced treatment methods. By examining a case study in Changsha City, the effectiveness of a comprehensive treatment system integrating various technologies is demonstrated. The review underscores the interconnectedness of human activities, environmental health, and waste management, emphasizing the importance of a holistic approach. It stresses the continuous improvement of leachate treatment technologies and the adoption of sustainable practices to reduce the environmental footprint of landfills. Ultimately, it calls for integrating multiple treatment processes, economic considerations, and readiness to address future challenges in landfill leachate treatment, contributing to the advancement of sustainable waste management practices. [ABSTRACT FROM AUTHOR]

Municipal solid waste management (MSWM) is an exigent and emerging problem in India. Despite various MSWM options, landfill continues to be the ultimate disposal destination of solid waste leading to ecosystem damage and leachate generation. The appropriate MSWM options and landfill leachate treatment become a matter of great apprehension to avoid negative impacts on the surrounding environment. In the present study, three LCA-based potential scenarios of systematic solid waste management, including anaerobic digestion, composting and landfilling, were analyzed and compared. The life cycle assessment (LCA) model was created in the Gabi 17.00 software for analyzing the impact of every steps involved in the MSWM system. Further, the study also focuses on leachate management of the Bhandewadi landfill site, situated in Nagpur City, India, using five different types of adsorbents, viz. rice husk, granular activated charcoal, powdered activated charcoal, compost and fly ash. Among the different scenario's analyzed and various impact categories studied, the LCA of all the three scenarios highlights that the global warming potential and human toxicity potential of scenario one is comparatively lower than other scenarios. Further, the adsorbents used in the study have potential for the removal of containments. The diffusion profile analysis of leachate through different types of adsorbents used revealed that the chemical oxygen demand removal efficiency enhances with thickness of the adsorbent. The study emphasized that it is crucial for decision-makers associated with waste management sector to focus on environment friendly MSWM approaches. It is also recommended that the decision and policymakers adhere and follow the stringent implementation of laws and regulations associated to the MSWM system. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dissolved organic matter (DOM) in landfill leachate impacts the toxicity, bioavailability, and migration of heavy metals. The present study investigated the complexation of heavy metals (Cu2+ and Pb2+) with DOM from two landfill leachate samples, representing an old landfill site containing incineration residues and incombustible waste. The logarithms of the stability constant (log KM) and percentage of complexed fluorophores were calculated using both the Ryan–Weber non-linear model and the modified Stern–Volmer model, yielding good agreement. The log KM values (at pH = 6.0 ± 0.1) calculated using both methods for the two sampling points were 5.02–5.13 and 4.85–5.11 for Cu2+–DOM complexation, and 5.01–5.13 and 4.46–4.87 for Pb2+–DOM complexation, respectively. Log KM was slightly higher for binding of DOM with Cu2+ than Pb2+, and the quenching degree was stronger for complexation with Cu2+ (28.5–30.6% and 38.0–45.9%) than Pb2+ (6.5–7.1% and 10.0–15.4%) in both leachate samples. While log KM values were similar, differences in the contributions of functional groups and molecular composition led to varying degrees of quenching. This study reveals the potential for heavy metal binding by DOM in landfill leachate with a unique solid waste composition and emphasizes variations in fluorescence quenching between Cu2+ and Pb2+ despite similar log KM levels. These findings may be useful for assessing heavy metal behavior in landfill leachate and its impacts on the surrounding environment. [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]

Copyright of Technology of Water Treatment is the property of Technology of Water Treatment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technology of Water Treatment is the property of Technology of Water Treatment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria are the key functional microorganisms needed to achieve simultaneous nitrification and denitrification (SND). In this study, 25 strains of HN-AD bacteria were successfully isolated from a stable landfill leachate biochemical treatment system, of which 10 strains belonged to Firmicutes and 15 strains belonged to Proteobacteria. Bacillus subtilis F4 and Alcaligenes faecalis P4 displayed good tolerance at a wide range of ammonia nitrogen (NH4+-N) concentrations. When the C/N ratio was 20, the removal rates of ammonia nitrogen were 90.1% and 89.5%, and the chemical oxygen demand (COD) removal rates were 92.4% and 93.9%, respectively. The napA gene encoding periplasmic nitrate reductase (Nap) and the nirS gene encoding nitrite reductase (Nir) were detected, and nitrogen balance showed assimilation and HN-AD was the main nitrogen metabolism mode in both strains. The use of immobilization materials could increase removal rate of ammonia nitrogen by 21.1% and 29.6%, respectively. The research results of this work can provide theoretical basis and technical support for the practical application of HN-AD bacteria to enhance the treatment of high ammonia nitrogen wastewater with high efficiency and low consumption. [ABSTRACT FROM AUTHOR]

Sanitary leachate from urban landfills is known to be contaminated with multi-metals and residual antibiotics. Current research edges on exploring the multi-metal and antibiotic sensitivity profile of four indigenous strains, “Brevibacillus spp. Leclercia spp. Pseudescherichia spp., and Brucella spp.” isolated from the leachate of a sanitary landfill in a tropical region. Indigenous isolates were observed to be antibiotic-resistant and have high tolerance against eight of the ten tested metals except Cu & Co. It was observed that interaction with multi-metals in laboratory conditions significantly altered the cell morphology of bacterial strains, as depicted by Scanning Electron Microscope. Metal adsorption onto the microbial surface was deciphered through Electron Dispersive Spectrometer analysis and elemental mapping. Application of isolated strains into real-time leachate matrix exhibits a complete reduction of Ag and Zn and for other tested metals. Their response to these toxicants may facilitate their application in bioremediation-based treatment technologies for urban landfill leachate. [ABSTRACT FROM AUTHOR]

Elucidating the characteristics of dissolved organic matter (DOM) is crucial to assessing its impact on the bioavailability and mobility of pollutants in landfill leachate. This study reports a comprehensive 5–month investigation into the characteristics of DOM in leachate from an old Japanese landfill, collected at six different sampling points. The molecular composition, chemical properties, and structural characteristics of DOM were assessed using Orbitrap mass spectrometry and spectral analysis. The leachate DOM mainly consisted of CHO-containing molecules (58.5–88.9%), low-oxygen unsaturated phenolic compounds (40.5–54.0%), and aliphatic compounds (19.4–47.3%), with slight variation among sampling points. A significant portion of the nominal oxidation state of carbon was in the reduced zone (76.2–95.4%). The results underscore the distinct molecular composition of DOM in mature Japanese landfill leachate compared to young and mature leachates from other countries. Two of six sampling points, with notable differences in molecular characteristics, were compared and elucidated. The composition of landfill waste, rather than landfill age, was the main factor affecting the characteristics and differentiation of leachate DOM. [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]

A Gram-stain-negative, facultative anaerobe, rod-shaped strain JX-1T was isolated from UASB sludge treating landfill leachate in Wuhan, China. The isolate is capable of growing under conditions of pH 6.0–11.0 (optimum, pH 7.0–8.0), temperature 4–42 ℃ (optimum, 20–30 ℃), 0–8.0% (w/v) NaCl (optimum, 5.0%), and ammonia nitrogen concentration of 200–5000 mg/L (optimum, 500 mg/L) on LB plates. The microorganism can utilize malic acid, D-galactose, L-rhamnose, inosine, and L-glutamic acid as carbon sources, but does not reduce nitrates and nitrites. The major fatty acids are C18:1ω7c/C18:1ω6c, iso-C15:0, and anteiso-C15:0. The respiratory quinones are Q9 (91.92%) and Q8 (8.08%). Polar lipids include aminolipid, aminophospholipid, diphosphatidylglycerol, glycolipid, phosphatidylethanolamine, phosphatidylglycerol, and phospholipid. Compared with other strains, strain JX-1T and Denitrificimonas caeni HY-14T have the highest values in terms of 16S rRNA gene sequence similarity (96.79%), average nucleotide identity (ANI; 76.06%), and average amino acid identity (AAI; 78.89%). Its digital DNA-DNA hybridization (dDDH) result is 20.3%. The genome of strain JX-1T, with a size of 2.78 Mb and 46.12 mol% G + C content, lacks genes for denitrification and dissimilatory nitrate reduction to ammonium (DNRA), but contains genes for ectoine synthesis as a secondary metabolite. The results of this polyphasic study allow genotypic and phenotypic differentiation of the analysed strain from the closest related species and confirm that the strain represents a novel species within the genus Denitrificimonas, for which the name Denitrificimonas halotolerans sp. nov. is proposed with JX-1T (= MCCC 1K08958T = KCTC 8395T) as the type strain. [ABSTRACT FROM AUTHOR]

As a crucial hydrolytic enzyme, urease plays a vital role in anaerobic biological treatment. It is well-known that manganese ions are abundant in landfill leachate, but their concentration fluctuates significantly. However, few studies have investigated the effect and mechanism of different concentrations of Mn2+ on urease activity during anaerobic biological treatment of landfill leachate. This paper aimed to investigate the effects and mechanisms of different concentrations of Mn2+ on urease activity. The results showed that an appropriate amount of Mn2+ could significantly enhance urease activity, while a high concentration of Mn2+ could inhibit it. Insight into the mechanisms behind this phenomenon, various methods such as Zeta potential, particle size, ultraviolet spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and statistical analysis were employed in our study. Research suggested that, on one hand, Mn2+ may form hydrogen bonds with the side chain amino or carboxyl groups of urease amino acid residues, affecting the structure of urease through hydrogen bonding. Additionally, Mn2+ also binds to urease through hydrophobic interactions. On the other hand, the C–OH and C-N functional groups in urease have a strong affinity for Mn2+, and changes in these functional groups can greatly enhance the activity of urease. Furthermore, under the action of high concentrations of Mn2+, while the structure of urease becomes more stable, there is also a steric hindrance phenomenon that affects the substrate from entering the catalytic center. Therefore, studying the mechanism of Mn2+ affecting urease activity has significant biological significance and provides a new perspective for exploring the impact of metals on anaerobic bioprocessing of landfill leachate. [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]

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]

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]

Landfill leachate raises a huge risk to human health and the environment as it contains a high concentration of organic and inorganic contaminants, heavy metals, ammonia, and refractory substances. Among leachate treatment techniques, the biological methods are more environmentally benign and less expensive than the physical–chemical treatment methods. Over the last few years, fungal-based treatment processes have become popular due to their ability to produce powerful oxidative enzymes like peroxidases and laccases. Fungi have shown better removal efficiency in terms of color, ammonia, and COD. However, their use in the treatment of leachate is relatively recent and still needs to be investigated. This review article assesses the potential of fungi and fungal-derived enzymes in treating landfill leachate. The review also compares different enzymes involved in the fungal catabolism of organic pollutants and the enzyme degradation mechanisms. The effect of parameters like pH, temperature, contact time, dosage variation, heavy metals and ammonia are discussed. The paper also explores the reactor configuration used in the fungal treatment and the techniques used to improve leachate treatment efficacy, like pretreatment and fungi immobilisation. Finally, the review summarises the limitations and the future direction of work required to adapt the fungal application for leachate treatment on a large scale. [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]

Landfill leachate discharged into watercourse without proper treatment can pollute the water source due to its high chemical oxygen demand (COD). The high pollutant load in landfill leachate has become one of the potential substrates in bio-energy generation by using microbial fuel cell (MFC). MFC integrated with adsorption system has been introduced as an approach to overcome the limitation of stand-alone MFC, which is able to treat the landfill leachate more effectively while simultaneously generating bio-energy. Anode size has been reported to have a significant influence on the power generation of MFC via lab-scale experiments, however the simulation studies on MFC are still limited. This study aimed to develop a simulation model to predict the effect of graphite fiber brush anode size on the performance of a single chamber air-cathode hybrid MFC-Adsorption system, in terms of COD removal and bio-energy generation. The highest power density of 1.33 mW/m² was achieved with 20% anode brush removed. The highest current generation of 2.37 mA and voltage of 7.11 mV was obtained with the largest anode surface area of 0.1288 m² and resistance of 2.76 Ω. The highest COD consumption by electrogenic microorganisms was 4.96 x 10-9 Lmol/mg, and predicted to decrease with decreasing anode size. The efficiency of the simulation model could be further improved by incorporating parameters such as charge transfer kinetic at anode and cathode, adsorption effect by activated carbon as well as the substrate and microbial population behaviour. The simulation model developed was significant towards enhancing the bio-energy generation and reducing the cost of MFC for industrial application. [ABSTRACT FROM AUTHOR]

The effectiveness of using calcium peroxide (CP) to purify landfill leachate from organic and inorganic contamination has been studied under laboratory conditions using samples from a landfill as an example. The degree of purification is assessed depending on the size of the reagent added at CP/leachate ratios of 1/100, 1/50, 1/20, and 1/10 and the duration of its contact with the leachate from 1 to 3 days. The data we obtained indicate an improvement in the quality of wastewater as a result of treatment with calcium peroxide: a decrease in the concentration of heavy metals, inorganic anions, COD, etc. The results of the study support the prospects of using CP at the initial stage of cleaning of landfill leachate. [ABSTRACT FROM AUTHOR]

Humic acids (HAs) produced during the landfill on Cr(VI) fate and their combined impact on the anaerobic digestion (AD) process has not yet been fully elucidated. This study systematically evaluated the interactions and mechanism of HAs on the AD of Cr(VI)-contaminated leachate. Results indicated that high concentrations of HAs (i.e., 200, 500, 1000 mg/L) detoxified the Cr(VI) on AD and the maximum methane production of 1011.63 ± 248.01 mL/g COD was obtained at 500 mg/L HAs, representing an 18.4% increase compared to the control group. Mechanistic studies demonstrated that high concentrations of HAs (i.e., C4-C5) detoxified the Cr(VI) on AD via adsorption and reduction, and the enhanced direct interspecies electron transfer (DIET) played an important role in methane production. The adsorption capacity (32.89 mg Cr(VI)/g HAs) was significantly higher than the granular sludge (3.29 mg Cr(VI)/g TS) and adsorbed Cr(VI) was reduced to less toxic Cr(III) due to the presence of functional groups of HAs (e.g., hydroxyl and phenolic groups), achieving detoxification of Cr(VI) on AD. The increase of viable microbial cells proved the detoxification of high HAs concentrations. Moreover, the increase in the abundance of Syntrophomonas and Methanosaeta has led to the higher methane production at high HAs concentration. [ABSTRACT FROM AUTHOR]

Landfilling is the most popular, economical and simple method for disposing a wide range of waste, which on the other hand beyond doubt serves as a reservoir of toxic substances. The leachate that are released from the contaminants affects the surrounding soil, groundwater and human health. Apart from harbouring contaminants from different sources like pharmaceuticals, medical, livestock, domestic wastes, heavy metals etc., landfill leachates (LFLs) facilitate the survival and dissemination of antibiotic resistance genes (ARGs). Due to the increased population which is directly proportional to the amount of waste produced requires more stringent protocol for the control and treatment of waste that is being dumped. The current review illustrates a panoramic view on the ARGs in the LFLs that includes the occurrence, source, treatment technologies and the scientometrics to analyse the research hotspots. The literature survey confirmed that only a limited number of studies have been reported so far for removal of ARGs in LFLs and still search for a cost effective, streamlined and ubiquitous method of treatment has never ceased. This could be due to the increase as well as the detrimental nature of ARGs, hence a few suitable methods already proposed for removal of ARGs from various sources and their challenges have also been discussed, to provide an insight of different methods to be investigated in LFLs. [ABSTRACT FROM AUTHOR]

The burgeoning issue of landfill leachate, exacerbated by urbanization, necessitates evaluating its biological impact, traditionally overshadowed by physical and chemical assessments. This study harnesses Caenorhabditis elegans, a model organism, to elucidate the physiological toxicity of landfill leachate subjected to different treatment processes: nanofiltration reverse osmosis tail water (NFRO), membrane bioreactor (MBR), and raw leachate (RAW). Our investigation focuses on the modulation of sugar metabolism, particularly trehalose—a disaccharide serving dual functions as an energy source and an anti-adversity molecule in invertebrates. Upon exposure, C. elegans showcased a 60–70% reduction in glucose and glycogen levels alongside a significant trehalose increase, highlighting an adaptive response to environmental stress by augmenting trehalose synthesis. Notably, trehalose-related genes in the NFRO group were up-regulated, contrasting with the MBR and RAW groups, where trehalose synthesis genes outpaced decomposition genes by 20–30 times. These findings suggest that C. elegans predominantly counters landfill leachate-induced stress through trehalose accumulation. This research not only provides insights into the differential impact of leachate treatment methods on C. elegans but also proposes a molecular framework for assessing the environmental repercussions of landfill leachate, contributing to the development of novel strategies for pollution mitigation and environmental preservation. [ABSTRACT FROM AUTHOR]

Landfill leachate contains a significant amount of organic matter, making it a valuable source for CH4 production. However, due to its liquid form, the mono-digestion of leachate could result in a reduced CH4 yield per unit reactor volume. This necessitates its utilization in anaerobic digesters alongside solid waste streams. The objective of this study was to evaluate co-digestion performance of landfill leachate with different wastes using biomethane potential test and assess the optimum combination in terms of CH4 productivity. Modified Gompertz model was used for kinetic characterization. Experiments were held under mesophilic conditions and lasted for 30 days. Among mono-digestion of substrates, landfill leachate exhibited the highest CH4 productivity and yield: 83.17 mL/gVS.d and 793 ± 6.85 mL/gVS, respectively. Fish waste was found to have the lowest energy potential with 350 mL/gVS CH4 yield and 18.24 mL/gVS.d CH4 productivity. CH4 productivities for co-digestion cases ranged from 5.48 to 67.85 mL/gVS.d. Mixing landfill leachate and chicken manure with the same amount on wet weight basis yielded the highest CH4 productivity. On the other hand, inclusion of fish waste consistently resulted in decreased CH4 yield and productivity for all incubations, which suggests that fish waste may not be suitable as a co-substrate for landfill leachate in terms of CH4 production. Monitoring of chemical parameters revealed that buffering capacity of the system and free ammonia formation were the main parameters governing CH4 production. [ABSTRACT FROM AUTHOR]

Landfill leachate contributes to groundwater pollution. The Permeable Reactive Barrier (PRB) is a sustainable in-situ method to remediate groundwater. Finding cost-effective and efficient reactive materials is a key problem with PRBs. Hence, the present study aimed to assess the applicability of two composite reactive media beds derived from several waste materials (building waste, sludge, sea sand, iron particles, bagasse, saw dust, bio char, fly ash and coconut coir pith) for PRBs to treat groundwater contaminated by landfill leachate. The study comprised two identical laboratory-scale PRB reactors: an experimental reactor and a control reactor. Each reactor included two reactive media beds in series. In the experimental reactor, one of the two beds was filled with a composite reactive media derived from waste materials with high particle densities, while the other was filled with waste materials of low particle densities. In contrast, both the beds of the control reactor were filled with Granular Activated Carbon (GAC). The experimental PRB demonstrated removal rates of 97.08 ± 0.11% (Pb), 65.01 ± 2.14% (Mn), 55.03 ± 1.06% (Fe) and 78.34 ± 1.58% (COD). The control reactor achieved removal rates of 99.26 ± 0.08% (Pb), 94.46 ± 1.13% (Mn), 80.23 ± 0.93%(Mn) and 98.83 ± 0.14% (COD). The shear strength reductions were 19%, 27%, and 11% for the high-density, low-density, and GAC beds, respectively. The associated reductions in hydraulic conductivity were 24%, 12%, and 35%. The waste-derived reactive media possess multiple properties sourced from different materials and can address the removal of multiple contaminants simultaneously, comparable to GAC. [ABSTRACT FROM AUTHOR]

The Anaerobic Baffled Reactor (ABR) is an effective solution for landfill leachate treatment using an anaerobic fermentation process, which helps to reduce operating costs and sludge volume. To better understand the biological, chemical, and physical processes involved, especially when combining the ABR with an aerobic component, the study aimed to investigate the performance of an Anaerobic–Aerobic Hybrid Baffled Reactor (AABR) that includes an Anaerobic Filter (AF) for treating landfill leachate. This research utilized two glass reactors. The first reactor, designated as AABR-AF, consisted of six independent rectangular glass chambers arranged side by side. The third and sixth chamber designed for aerobic treatment and AF, respectively. The second reactor was used as a control reactor and did not include any aerobic chamber. The highest Removal Efficiencies (REs) for turbidity, COD, BOD, TP, TKN, nitrate, TOC, and TSS in the AABR-AF and ABR-AF were found to be (65.4% and 56.3%), (98.3% and 94.1%), (98.1% and 93.2%), (86.4% and 65%), (89.2% and 76.7%), (81.2% and 64.4%), (88.2% and 79.4%), and (72.4% and 68.5%), respectively. These optimal REs were achieved at an HRT of 48 h and an OLR of 10 kg/m3.d. Also, the highest and the lowest REs in Heavy Metals (HMs) were 89.57% for manganese in AABR-AF and 6.59% for nickel in ABR-AF, in an OLR of 10 kg/m3.d, respectively. The effective removal of Organic Matters (OMs) from landfill leachate using the AABR-AF and ABR-AF was found to be strongly influenced by HRT and OLR. The AABR-AF configuration, featuring a single aerobic chamber in the reactor, exhibited a higher efficiency in removing OMs compared to the ABR-AF configuration. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: The utilization of stabilization pond system for landfill leachate treatment is hindered by its requirement for expansive land areas and extended retention periods. Although the system effectively removes organic compounds, its ability to eliminate nutrients such as nitrogen and phosphorus is comparatively limited. Consequently, the leachate subjected to treatment often falls short of meeting the mandated standards for effluent quality. In response to this challenge, a research study was undertaken to investigate the potential of utilizing a consortium comprising microalgae and bacteria in the treatment of landfill leachate. METHODS: The microalgae, bacteria, and leachate utilized in this study were sourced from a leachate treatment facility located at the Aceh regional domestic waste management unit in Blang Bintang, Aceh Besar, Indonesia. The two glass photobioreactors were operated batchwise, where the first was provided with a combination of air and carbon dioxide, and the other was solely exposed to air. The pollutant removal efficacy in the leachate effluent was assessed through the measurements of chemical oxygen demand, ammonia, nitrate, nitrite, and phosphate concentrations. Subsequently, macroscopic identification of microalgae and bacteria species was also conducted. FINDINGS: Utilizing a consortium of microalgae and bacteria has demonstrated efficacy in treating leachate, resulting in a notable reduction of contaminants within the effluent. The symbiotic association between microalgae and bacteria in the context of leachate waste treatment is evident. The bacteria's metabolic actions result in carbon dioxide emission, which subsequently serves as a substrate for the photosynthetic activities of the microalgae. The microalgae facilitate the transfer of oxygen, produced through photosynthesis, to the bacteria to support their metabolic processes. Therefore, introducing exogenous carbon dioxide to the consortium yields minimal discernible effects, given that the bacteria adequately fulfill the carbon dioxide requirements of the microalgae. This discovery enhances the efficacy of leachate treatment techniques by leveraging the utilization of pre-existing mixed cultures of microalgae and bacteria found in leachate facilities. CONCLUSION: This study evaluated the microalgae-bacteria consortium's effectiveness in reducing leachate pollutants. The consortium exhibited a significant capability, achieving a 75 percent reduction in chemical oxygen demand and successfully eliminating a range of contaminants. Additionally, it demonstrated effective removal of nitrogen compounds such as ammonia, nitrate, and nitrite, with removal rates reaching 75 percent. Notably, the consortium showed a 99 percent removal rate for phosphate compounds. Even with the introduction of carbon dioxide, the pollutant removal remained consistently high, suggesting that the addition of carbon dioxide did not significantly influence the overall process. [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]

Changes in the activated sludge performance in an anaerobic/aerobic biological treatment system for leachate was discussed under the condition of tetracycline (TC) exposure. The results show that a low concentration of TC did not have an obvious effect on the removal of chemical oxygen demand (COD) while a high concentration of TC had a certain promoting effect. Under the stimulation of TC, the particle size distribution of anaerobic/aerobic sludge tended to be more uniform, the particle size of anaerobic sludge decreased while the settleability increased; however, the particle size of aerobic sludge increased due to bulking. With the addition of TC, the concentration of most heavy metal ions in sludge samples increased.TC exposure results in the release of a large amount of extracellular polymeric substances (EPS), thus leading to a smoother surface of anaerobic sludge and a rougher surface of aerobic sludge. The high removal efficiency of COD under the high concentration of TC was also presumed to be due to EPS promoting the microbial absorption of anaerobic substances in the leachate. The results clearly showed that TC had a bacteriostatic effect. After antibiotic exposure, the abundance and diversity index of bacteria in each reactor decreased obviously, the microbial community evolved, and the dominant species at the genus and phylum levels of anaerobic/aerobic reactors changed. This study provides a better understanding the effect of TC on activated sludge and has reference value for the management of antibiotic exposure in leachate treatment facilities. [ABSTRACT FROM AUTHOR]

This study applied ultraviolet/peroxymonosulfate (UV/PMS) and UV/hydrogen peroxide (UV/H2O2) processes to the advanced treatment of membrane bioreactor (MBR) effluent. The degradation efficiency of refractory organic matter and the reaction mechanisms of the two processes were systematically investigated. The results showed that the degradation efficiency of the UV/PMS processes was significantly lower than that of the UV/H2O2 process when the PMS concentration was significantly lower than the H2O2 concentration, e.g. the UV254 removals under optimal conditions were 72.92% and 82.21%, respectively. Additionally, the UV/PMS process could operate over a broader pH range. The degradation efficiency of the UV/PMS process was slightly increased by HCO3– and Cl- due to the activation of PMS, while in the UV/H2O2 process, HCO3- and Cl- depressed the degradation efficiency by competing with organic matter to react with reactive oxygen species (ROS). After the two processes, the aromaticity, humification, condensation degree, and molecular weight of refractory organic matter in the MBR effluent were considerably decreased. Fulvic- (HA) and humic-like substances (FA) were greatly degraded by the two processes. The UV/PMS had a superior degradation efficiency for macromolecular HA in the early stage of the reaction, and the UV/H2O2 could degrade HA to protein-like substances in the latter stage of the reaction. These differences between the two processes could be attributed to the dominance of different ROS, with SO4•- and HO• dominating in the UV/PMS, and HO• dominating in the UV/H2O2. The results of this study provide theoretical support for the application of MBR effluent treatment. Highlights Comparison on the MBR effluent treatment of UV/PMS and UV/H2O2 is studied. UV/PMS process can better destroy humic-like substances in the early reaction stage. Humic-like substances are transformed into protein-like compounds in UV/H2O2 process. UV/PMS and UV/PMS performs differently due to their different dominant ROS. [ABSTRACT FROM AUTHOR]

Landfill leachate is a mixture of highly concentrated organic and inorganic pollutants and needs to be treated properly due to their toxicity and serious adverse effects on the environment. Recently, advanced oxidation processes have been successfully applied for leachate treatment. In this study, the removal of chemical oxygen demand (COD), total organic carbon (TOC) and absorbable organic halogens (AOX) in waste leachate stabilized by the electro-Fenton (EF) process, which is one of the advanced oxidation processes, was investigated. For this purpose, a jacketed reactor in which the electrochemical process takes place was designed and iron electrodes were used for maintenance and cost efficiency in this process. Within the scope of the study, the efficiency of the important process parameters, such as pH, current density, catalyst amount, oxidant dose and electrolysis time, was determined and their values were optimized. Optimum values were found to be as pH 3, current density 150 A/m2, hydrogen peroxide amount 500 mg/L and electrolysis time 10 min. The best removal efficiencies were obtained as 71.7% COD, 97.4% AOX and 90.87% TOC under optimum conditions. In addition, within the scope of this study, the collapsibility and operating costs of the sludge having formed as a result of the EF process were also examined. It has been observed that especially the sludge formed as a result of the EF process has good settling properties. When the results were evaluated, it was confirmed that the EF process can be used efficiently to break down leachate organics in terms of wastewater quality and discharge limits. [ABSTRACT FROM AUTHOR]

Banana peels can be a valuable adsorbent for reducing heavy metals in water. This study investigated the effect of chemical activators on Nipah banana peel (Musa acuminata balbisiana) on their ability to reduce Pb and Cd metals in landfill leachate. Before the adsorption test, the banana peels were treated with a different chemical activator, including detergent, NaOH, KOH, and H3PO4. The results showed that H3PO4 adsorbs relatively high amounts of metals (Pb-75.800%, Cd-18.491%) in landfill leachate among these activators. FTIR analysis showed that banana peels treated with H3PO4 produced sharper carbonyl or carboxyl group peaks. These groups are very influential in the metal adsorption process. SEM-EDS analysis of the H3PO4-treated banana peels showed an increase in carbon and oxygen elements in the banana peels and changes in the pore surface that enhanced the adsorption process on Pb and Cd metals. From this study, banana peels activated with H3PO4 showed great potential to be developed into adsorbents to reduce heavy metal concentration. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment despite global regulatory action to restrict their use in industrial processes and products. The objective of this reconnaissance sampling was to understand current industrial use and ongoing sources of PFAS in Ontario. Fourteen PFAS were analyzed in effluents from four sectors: electroplaters, laundry and carpet cleaners, landfills, and circuit board manufacturers that discharge to sewersheds connected to wastewater treatment plants. Maximum concentrations were detected in carpet cleaning wastewater: 79,000 ng/L for perfluorohexane sulfonate (PFHxS), 26,000 ng/L perfluorooctane sulfate (PFOS), and 9400 ng/L perfluorooctanoic acid (PFOA). Total summed PFAS (∑PFAS14) concentrations were highest in laundry and carpet cleaners > electroplaters > landfill leachate > circuit boarders. These results indicate that PFAS continue to be used in select manufacturing and processing facilities and that the elevated levels are associated with past and current uses in commercial products. [ABSTRACT FROM AUTHOR]

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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]

Refractory substances (humus) and salts (chloride (Cl−) and sulphate (SO42−) ions) remain in the biotreated landfill leachate treatment, and it is necessary to carry out further treatments by a suitable method before discharge. In this study, the effect and operational mechanism of a combination of the coagulation Fe0/H2O2 and ultra-high lime aluminium (UHLA) processes for the treatment of refractory organic substances and salts in the leachate effluent of a semi-aerobic aged refuse biofilter (SAARB) were investigated. The results showed that polyferric sulphate is a relatively efficient coagulant comparing to FeCl3, Al2(SO)4, and polyaluminium chloride. The Fe0/H2O2 process further removed refractory organics from wastewater, achieving 49.8% of total organic carbon removed. Further treatment by the UHLA process was carried. The results demonstrated that the amount of precipitant, reaction duration, and temperature had a significant impact on the Cl− and SO42− removals. After three treatments, the cumulative SO42− and Cl− removal efficiencies were 98% and 80%, respectively. The SO42− and Cl− were removed in the form of precipitates such as UHLA, specific components of which included calcium alumina, Fremy's salt of calcium, aluminium chloride, and calcium hydroxide. Overall, the UV254, CN, Cl−, and SO42− removal efficiencies from the SAARB effluent were 94.08%, 98.73%, 79.96%, and 98.44%, respectively, for the combined coagulation Fe0/H2O2 and UHLA processes. Therefore, the combined processes could effectively remove residual pollutants in the biologically-treated landfill leachate, and the study provides a useful reference for the removal of refractory organic matter and salts in landfill leachate. Highlights Coagulation-Fe0/H2O2-UHLA process is effective to SAARB effluent treatment. Refractory organics are substantially degraded by the coagulation-Fenton-like stage. Both Cl− and SO42− in SAARB effluent are greatly removed by UHLA process. [ABSTRACT FROM AUTHOR]

Arsenic contamination of groundwater has affected human health and environmental safety worldwide. Hundreds of millions of people in more than 100 countries around the world are directly or indirectly troubled by arsenic-contaminated groundwater. In addition, arsenic contamination of groundwater caused by leakage of leachate from municipal solid waste landfills has occurred in some countries and regions, which has attracted widespread attention. Understanding how domestic waste landfill leachate affects the arsenic's migration and transformation in shallow groundwater is crucial for accurate assessment of the distribution and ecological hazards of arsenic in groundwater. Based on literature review, this study systematically summarized and discussed the basic characteristics of landfill leachate, the mechanism of arsenic pollution in groundwater, and the effect of landfill leachate on the migration and transformation of arsenic in groundwater. Combined with relevant research findings and practical experience, countermeasures and suggestions to limit the impact of landfill leachate on the migration and transformation of arsenic in groundwater are put forward. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During adaptation to waters that are rich in xenobiotics, biological systems pass through multiple stages. The first one is related to the restructuring of communities, pronounced destruction of the structure, and multiplication of active biodegradants. The purpose of the present research was to describe the microbiome restructuring that occurs during the adaptation stage in landfill leachate treatment. In a model SBR (sequencing batch reactor), a 21-day purification process of landfill leachate was simulated. Wastewater was fed in increasing concentrations. When undiluted leachate entered, the activated sludge structure disintegrated (Sludge Volume Index—4.6 mL/g). The Chemical Oxygen Demand and ammonium nitrogen concentration remained at high values in the influent (2321.11 mgO2/L and 573.20 mg/L, respectively). A significant amount of free-swimming cells was found, and the number of aerobic heterotrophs and bacteria of the genera Pseudomonas and Acinetobacter increased by up to 125 times. The Azoarcus-Thauera cluster (27%) and Pseudomonas spp. (16%) were registered as the main bacterial groups in the activated sludge. In the changed structure of the microbial community, Gammaproteobacteria, family Rhizobiaceae, class Saccharimonadia were predominantly represented. Among the suspended bacteria, Microbactericeae and Burkholderiaceae, which are known for their ability to degrade xenobiotics, were present in larger quantities. The enzymological analysis demonstrated that the ortho-pathway of cleavage of aromatic structures was active in the community. The described changes in the leachate-purifying microbial community appear to be destructive at the technological level. At the microbiological level, however, trends of initial adaptation were clearly outlined, which, if continued, could provide a highly efficient biodegradation community. [ABSTRACT FROM AUTHOR]