Bisphenol A in hazardous waste landfill leachates

The levels of bisphenol A in hazardous waste landfill leachates collected in Japan in 1996 were determined by gas chromatograph/mass spectrometer (GC/MS). Bisphenol A was found in seven of 10 sites investigated. All the hazardous waste landfills with leachates contaminated by bisphenol A were controlled. The concentrations of bisphenol A ranged from 1.3 to 17,200 microg/l with a median concentration of 269 microg/l. The source of bisphenol A in landfill leachates may be the waste plastics in waste landfill. The concentrations of bisphenol A in some samples exceeded the EC50 or LC50 levels for aquatic biota. Landfill leachates may be a significant source of bisphenol A found in the environment.     

Comparative analysis of trace contaminants in leachates before and after a pre-oxidation using a solar photo-Fenton reaction

Sanitary landfill leachates are a complex mixture of high-strength organic and inorganic persistent contaminants, which constitute a serious environmental problem. In this study, trace contaminants present in leachates were investigated by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector before and after a pre-oxidation step using a solar photo-Fenton process. More than 40 organic compounds were detected and identified as benzene (0.09?±?0.07 mg?L^-1), trichlorophenol (TCP) (0.18?±?0.12 mg?L^-1), phthalate esters (Di-n-butyl phthalate (DBP), Butyl benzyl phthalate (BBP), Di(2-ethylhexyl) phthalate (DEHP)) (DBP: 0.47?±?0.01 mg?L^-1; BBP: 0.36?±?0.02 mg?L^-1; DEHP: 0.18?±?0.01 mg?L^-1), among others. Toluene, pentachlorophenol, dimethyl phthalate, diethyl phthalate, and Di-n-octyl phthalate were never detected in any of the samples. After the photo-Fenton treatment process, TCP decreased to levels below its detection limit, benzene concentration increased approximately three times, and DBP concentration decreased about 77 % comparatively to the raw leachate sample. The solar photo-Fenton process was considered to be very efficient for the treatment of sanitary landfill leachates, leading to the complete elimination of 24 of the detected micropollutants to levels below their respective detection limits and low to significant abatement of seven other organic compounds, thus resulting in an increase of the leachate biodegradability.     

Estimation of the environmental risk posed by landfills using chemical, microbiological and ecotoxicological testing of leachates

The leachates from 22 municipal solid waste (MSW) landfill sites in Southern Poland were characterized by evaluation of chemical, microbiological and ecotoxicological parameters. Chemical analyses were mainly focused on the identification of the priority hazardous substances according to Directive on Priority Substances, 2008/105/EC (a daughter directive of the WFD) in leachates. As showed, only five substances (Cd, Hg, hexachlorobutadiene, pentachlorobenzene and PAHs) were detected in the leachates. The compounds tested were absent or present at very low concentrations. Among them, only PAHs were found in all samples in the range from 0.057 to 77.2 μg L⁻¹. The leachates were contaminated with bacteria, including aerobic, psychrophilic and mesophilic bacteria, coliform and fecal coliforms, and spore-forming-bacteria, including Clostridium perfringens, and with filamentous fungi. From the analysis of specific microorganism groups (indicators of environmental pollution by pathogenic or opportunistic pathogenic organisms) it can be concluded that the landfill leachates showed sanitary and epidemiological hazard. In the ecotoxicological study, a battery of tests comprised of 5 bioassays, i.e. Microtox®, Spirotox, Rotoxkit F™, Thamnotoxkit F™ and Daphtoxkit F™ magna was applied. The leachate samples were classified as toxic in 13.6%, highly toxic in 54.6% and very highly toxic in 31.8%. The Spirotox test was the most sensitive bioassay used. The percentage of class weight score was very high - above 60%; these samples could definitely be considered seriously hazardous and acutely toxic to the fauna and microflora.No correlations were found between the toxicity values and chemical parameters. The toxicity of leachate samples cannot be explained by low levels of the priority pollutants. It seems that other kinds of xenobiotics present in the samples at subacute levels gave the high aggregate toxic effect.The chemical, ecotoxicological and microbiological parameters of the landfill leachates should be analyzed together to assess the environmental risk posed by landfill emissions.     

Investigating the effect of landfill leachates on the characteristics of dissolved organic matter in groundwater using excitation–emission matrix fluorescence spectra coupled with fluorescence regional integration and self-organizing map

For the purpose of investigating the effect of landfill leachate on the characteristics of organic matter in groundwater, groundwater samples were collected near and in a landfill site, and dissolved organic matter (DOM) was extracted from the groundwater samples and characterized by excitation–emission matrix (EEM) fluorescence spectra combined with fluorescence regional integration (FRI) and self-organizing map (SOM). The results showed that the groundwater DOM comprised humic-, fulvic-, and protein-like substances. The concentration of humic-like matter showed no obvious variation for all groundwater except the sample collected in the landfill site. Fulvic-like substance content decreased when the groundwater was polluted by landfill leachates. There were two kinds of protein-like matter in the groundwater. One kind was bound to humic-like substances, and its content did not change along with groundwater pollution. However, the other kind was present as “free” molecules or else bound in proteins, and its concentration increased significantly when the groundwater was polluted by landfill leachates. The FRI and SOM methods both can characterize the composition and evolution of DOM in the groundwater. However, the SOM analysis can identify whether protein-like moieties was bound to humic-like matter.     

Estrogenic and dioxin-like potency in each step of a controlled landfill leachate treatment plant in Japan

The estrogenic activity (by E-screen bioassay), the concentrations of PCBs, PCDDs/PCDFs (and their resulting toxicity equivalents, TEQ) and several endocrine disrupting chemicals (EDCs: e.g., bisphenol A, nonylphenol, Butyl benzylpthalate (BBP), di-n-butylphthalate (DBP), 17alpha-ethynyl-estradiol or 4-octylphenol) have been analyzed from leachates of each step (before treatment, after biodegradation/sedimentation and after charcoal treatment) of a controlled landfill leachate treatment plant. The comparison of the effluent of the examined landfill leachate treatment plant with water from a nearby river in this study indicated no additional dioxin-like (e.g., TEQ: 0.027 compared to 1.01 pg TEQ/l; PCBs: 1.2 compared to 3.9 ng/l) or estrogenic impact (2.8 compared to 3.5 ng estradiol equivalents EE/l; analyzed by E-screen bioassay) from the leachate treatment plant into the surrounding water environment. The impact of dioxin-like compounds from uncleaned leachates into the final cleaned effluents could be sufficiently reduced by the leachate treatment plant for PCDDs (75%), PCDFs (62%), dioxin-like PCBs (97%), and the sum of TEQ (78%). The leachate treatment plant also achieved a reduction of the estrogenic activity as determined by E-screen (from 4.8 to 2.8 ng EE/l = 42%), by GC/MS for bisphenol A (>96% and nonylphenol (>98%) or by ELISA for estradiol (>80%). Additionally, for the validation of the E-screen, five known endocrine disrupting chemicals (EDCs: bisphenol A, BBP, DBP, 17 alpha-ethynyl-estradiol, 4-octylphenol) were analyzed. The EC50 values and estradiol equivalents factors (EEFs) for the five EDCs determined in this study were comparable to previously published data. The combined biological and chemical trace analysis data have provided valuable information on the relative contribution of natural, synthetic, and non-steroidal anthropogenic chemicals to the estrogenic and dioxin-like activity in leachates from a wastewater treatment plant, and water from a nearby river.     

Characterisation of odorants emissions from landfills by SPME and GC/MS

Odorous compounds from a landfill have been characterised by gas-chromatography-mass-spectrometry, identifying about 100 volatile organic compounds. Air samples from different landfill sites and from the environment have been analysed after a solid-phase microextraction on a three-phase fiber, DVB/Carboxen/PDMS, which allowed a preconcentration and the chromatographic data obtained from the most significant emission sources have been submitted to chemometric analysis in order to better establish specific markers of olfactory pollution. For example limonene was a typical tracer of fresh wastes, while p-cymene was characteristic of leachate and biogas. By the developed analytical procedure it has been evaluated the efficiency of a scrubber plant utilised in the landfill in order to remove malodour compounds. The average removal efficiency was not very high (about 23.5%) due to scarce ability in removing low polarity compounds. Furthermore, it has been demonstrated the suitability of a microgas chromatograph for the continuous on-site monitoring of air pollution in order to rapidly individuate emission sources of olfactive nuisances.     

Risk assessment and investigation of landfill leachate as a source of emerging organic contaminants to the surrounding environment: a case study of the largest landfill in Jinan City,China

Environmental Science and Pollution Research - Emerging organic contaminants (EOCs) have been widely studied in landfill leachates but not in the surrounding environment of landfills. In this...     

Evaluation of the leachability of polychlorinated dibenzo-p-dioxins and dibenzofurans in raw and solidified air pollution control residues from municipal waste incinerators

Leachability of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from raw and solidified air pollution control (APC) residues with selected solvents, including acetic acid, simulated acid rain, humic acid, linear alkylbenzene sulfonate (LAS) and n-hexane was investigated. High-chlorinated PCDD/F congeners were observed in all leachates of raw APC residue samples, with the largest total leaching concentration (61.60 ngm(-3); 0.30 ngI-TEQm(-3)) from treatment with humic acid. Low-chlorinated congeners were mainly leached with LAS and n-hexane. Solidification and stabilization (S/S) processes with cement and sulfur-containing chelating agent decreased the leachability of PCDD/Fs by up to 98% with humic acid and LAS as solvents. However, S/S processes enhanced the leachability of both high- and low-chlorinated PCDD/F congeners with n-hexane as the solvent, which largely increased the toxic equivalent quantity of leachates. These results suggest that conventional S/S processes may effectively restrain the release of PCDD/Fs when APC residues are leached with rain water or natural organic compounds (e.g., humic acid), but may have a deteriorated effect when APC residues are leached with nonpolar organic solvents (e.g., n-hexane) coexisting in the landfill sites.     

Quantitative determination of fluorochemicals in municipal landfill leachates

Twenty-four fluorochemicals were quantified in landfill leachates recovered from municipal refuse using an analytical method based on solid-phase extraction, dispersive-carbon sorbent cleanup, and liquid chromatography/tandem mass spectrometry. The method was applied to six landfill leachates from four locations in the US as well as to a leachate generated by a laboratory bioreactor containing residential refuse. All seven leachates had the common characteristic that short-chain (C₄-C₇) carboxylates or sulfonates were greater in abundance than their respective longer-chain homologs (?C₈). Perfluoroalkyl carboxylates were the most abundant (67 ± 4% on a nanomolar (nM) basis) fluorochemicals measured in leachates; concentrations of individual carboxylates reaching levels up to 2800 ng L⁻¹. Perfluoroalkyl sulfonates were the next most abundant class (22 ± 2%) on a nM basis; their abundances in each of the seven leachates derived from municipal refuse were greater for the shorter-chain homologs (C₄ and C₆) compared to longer-chain homologs (C₈ and C₁₀). Perfluorobutane sulfonate concentrations were as high as 2300 ng L⁻¹. Sulfonamide derivatives composed 8 ± 2.1% (nM basis) of the fluorochemicals in landfill leachates with methyl (C₄ and C₈) and ethyl (C₈) sulfonamide acetic acids being the most abundant. Fluorotelomer sulfonates (6:2 and 8:2) composed 2.4 ± 1.3% (nM basis) of the fluorochemicals detected and were present in all leachates.     

用聚硅酸铁铝对垃圾渗沥液进行预处理的研究

采用一种新型高效的无机高分子混凝剂——聚硅酸铁铝(PSAF)用于垃圾渗沥液亚滤装置的预处理。结果表明，在PSAF的投加量为150mg/L，pH为5．0和沉降时间为60min的条件下，混凝效果最佳，浊度去除率可达92％左右，色废去除率可达91％左右，CODcr去除率可达70％左右。同时探讨了该混凝剂处理垃圾渗沥液的反应机理。     

Magnetic ion exchange treatment of stabilized landfill leachate

Stabilized landfill leachate is characterized by a high concentration of non-biodegradable organic matter, which is similar in chemistry to dissolved organic matter (DOM) in the natural aquatic environment. Magnetic ion exchange (MIEX) resin treatment is well-studied in drinking water for removal of DOM from natural waters. There are fewer studies evaluating MIEX treatment of waste waters, and there is no previous work evaluating MIEX treatment of landfill leachate. This work systematically evaluated MIEX treatment of stabilized landfill leachate and evaluated the results in the context of previous studies of MIEX treatment of natural and waste waters. Five leachates from four landfills were evaluated as a function of MIEX resin dose, mixing time, and regeneration efficiency. MIEX resin removed DOM from landfill leachate, even in the presence of a reported high background concentration of inorganic ions. MIEX resin that was exhausted with leachate DOM was effectively regenerated with a concentrated NaCl solution, and regenerated MIEX resin performed similarly to virgin resin. For a majority of the leachates, the removal trend for MIEX resin was color > UV-absorbing substances > dissolved organic carbon ≈ COD > total nitrogen. Finally, MIEX resin removed a wider range of DOM from leachate than coagulation. The most important contribution of this work is that MIEX treatment of leachate followed very similar trends as MIEX treatment of natural waters, which will allow previous MIEX data to be used to estimate the treatment efficiency of other waste waters.     

电解氧化处理难降解垃圾渗滤液研究

采用连续式电解槽对垃圾渗滤液进行电解催化处理,考察极板间距、电流密度、电导率[Cl-]浓度对电解效果的影响.结果表明,当添加的[Cl-]6000 mg/L,在电解60 min时,对初始COD小于3000 mg/L的中等浓度渗滤液有较好的处理效果,COD和NH3-N的去除率分别达88.9%和97.3%,能耗为2.75 kwh/m3.为中试和工业设计应用提供了参考.     

Municipal landfill leachate-soil interactions: a kinetic approach

On investigating the effects of municipal landfill leachates on soils, it is found that the adsorption of landfill leachate constituents creates a "new" soil surface able to enhance heavy metal uptake. In particular, the treatment of soil with the total leachates led to an increase in its metal retention capability that was much higher than for each individual fraction. Results show that the leachate sorption on soil is regulated by the presence of leachate constituents with low molecular weight cut-off since these fractions are able to "accelerate" the sorption of higher molecular weight fractions. The rapidly sorbed lower molecular weight fractions create a different soil surface that is able to accommodate the high molecular weight constituents.     

Acute toxicity of leachates of tire wear material to Daphnia magna--variability and toxic components

Large amounts of tire rubber are deposited along the roads due to tread wear. Several compounds may leach from the rubber and cause toxicity to aquatic organisms. To investigate the toxic effects of tire wear material from different tires, rubber was abraded from the treads of twenty-five tires. Leachates were prepared by allowing the rubber to equilibrate with dilution water at 44 degrees C for 72 h. Then the rubber was filtered from the leachates, and test organisms (Daphnia magna) were added. Forty-eight hour EC50s ranged from 0.5 to >10.0 g l(-1). The toxicity identification evaluation (TIE) indicated that non-polar organic compounds caused most of the toxicity. UV exposure of the filtered tire leachates caused no significant increase in toxicity. However, when tested as unfiltered leachates (the rubber was not filtered from the leachates before addition of D. magna) photo-enhanced toxicity was considerable for some tires, which means that test procedures are important when testing tire leachates for aquatic (photo) toxicity. The acute toxicity of tire wear for Daphnia magna was found to be <40 times a predicted environmental concentration based on reports on the concentration of a tire component found in environmental samples, which emphasizes the need for a more extensive risk assessment of tire wear for the environment.     

Identification of some plasticizers compounds in landfill leachate

In this work it was described a simple method for extraction of plasticizer compounds (mainly phthalate esters and bisphenol A (BPA)) from landfill leachate samples. The samples were submitted to an extraction procedures based on precipitation, solid phase extraction (SPE) and ionic exchange chromatography (IEC). Firstly the landfill leachate sample was acidified by addition of HCl concentrated, in order to precipitate the organic compounds that are less soluble in water. The precipitate was washed with several solvents. The aqueous phase was then submitted to SPE with XAD-4 resin and IEC with Amberlyst A-27 resin. The instrumental analysis was performed by gas chromatography with mass spectrometer detector (GC/MSD) and the compounds were identified by the GC/MSD library (Wiley) and by using some standard substances. These methodologies allow the isolation and identification of the following compounds: dioctylphthalate, diisobutilphthalate, BPA, benzoic acid, palmitic acid and diisopentylphthalate. The methods are very simple, rapid and selective, for plasticizers extraction from landfill leachate matrices.     

Landfill leachate effects on sorption of organic micropollutants onto aquifer materials

The effect of dissolved organic carbon as present in landfill leachate, on the sorption of organic micropollutants in aquifer materials was studied by laboratory batch and column experiments involving 15 non-polar organic chemicals, 5 landfill leachates and 4 aquifer materials of low organic carbon content. The experiments showed that hydrophobic organic micropollutants do partition into dissolved organic carbon found in landfill leachate potentially increasing their mobility. However, landfill leachate interacted with aquifer materials apparently increases the sorbent affinity for the hydrophobic micropollutants. The combination of these two mechanisms affected the observed distribution coefficients within a factor of two, in some cases increasing and in other cases decreasing the sorption of the chemicals. No means for prediction of the effect is currently available, but from a practical point of view, the effect of landfill leachate on retardation of organic micropollutants in aquifer material seems limited.     

Heavy metal binding capacity (HMBC) of municipal solid waste landfill leachates

This research describes the use of a toxicity assay for the identification of metal toxicity, bioavailability and heavy metal binding capacity (HMBC) of municipal solid waste (MSW) landfill leachates. MetPLATE, an assay specific for heavy metal toxicity, was used to determine the HMBC of MSW leachates collected from 14 sites in Florida, with a wide range of chemical and physical characteristics. The leachates displayed a low toxicity which was attributed to the site-specific parameters, including, high concentrations of both organic and inorganic ligands. The HMBC test was undertaken to measure the effect of these site-specific parameters on metal toxicity. The potential for MSW leachate to bind and, thus, detoxify heavy metals was investigated with copper, zinc, and mercury. The HMBC values obtained ranged from 3 to 115, 5 to 93 and 4 to 101 for HMBC-Cu+2, HMBC-Zn+2, and HMBC-Hg+2, respectively. Additionally, the high strength leachates displayed the highest binding capacities, although the landfills sampled represented a wide range of characteristics. For comparison, the HMBC values reported with local lake water, Lake Alice and Lake Beverly, and a wastewater treatment plant effluent were all below 3. A partial fractionation of MSW leachate samples from sites 1, 5 and 8, was conducted to further investigate the influence of selected site-specific physico-chemical parameters on metal binding. The fractionation revealed that the HMBC of the leachate samples was heavily influenced by the concentration of solids, organics and hardness.     

Pilot monitoring study of ibuprofen in surface waters of north of Portugal

Ibuprofen is amongst the most worldwide consumed pharmaceuticals. The present work presents the first data in the occurrence of ibuprofen in Portuguese surface waters, focusing in the north area of the country, which is one of the most densely populated areas of Portugal. Analysis of ibuprofen is based on pre-concentration of the analyte with solid phase extraction and subsequent determination with liquid chromatography coupled to fluorescence detection. A total of 42 water samples, including surface waters, landfill leachates, Wastewater Treatment Plant (WWTP), and hospital effluents, were analyzed in order to evaluate the occurrence of ibuprofen in the north of Portugal. In general, the highest concentrations were found in the river mouths and in the estuarine zone. The maximum concentrations found were 48,720 ng?L^?1 in the landfill leachate, 3,868 ng?L^?1 in hospital effluent, 616 ng?L^?1 in WWTP effluent, and 723 ng?L^?1 in surface waters (Lima river). Environmental risk assessment was evaluated and at the measured concentrations only landfill leachates reveal potential ecotoxicological risk for aquatic organisms. Owing to a high consumption rate of ibuprofen among Portuguese population, as prescribed and non-prescribed medicine, the importance of hospitals, WWTPs, and landfills as sources of entrance of pharmaceuticals in the environment was pointed out. Landfill leachates showed the highest contribution for ibuprofen mass loading into surface waters. On the basis of our findings, more studies are needed as an attempt to assess more vulnerable areas.     

The application of novel coagulant reagent (polyaluminium silicate chloride) for the post-treatment of landfill leachates

Relatively "old" (stabilized) landfill leachates are a special category of wastewaters, which are difficult to treat further, mainly due to their bio-refractory organic content (humic substances). In this study, coagulation-flocculation was examined as post-treatment method for the biologically pre-treated stabilized leachates. The purpose was to examine the coagulation performance of alternative coagulant agents, i.e. the composite coagulant polyaluminium silicate chloride. Composite coagulants with different Al to Si molar ratio and different preparation methods were tested. Their efficiency was evaluated by monitoring from turbidity and phosphate content, other parameters strongly correlated with the presence of organic matter, such as UV absorbance at 254nm, COD and colour. The results suggest that the silica-based coagulants exhibit better coagulation performance, than the relevant conventional coagulant (alum) or simple pre-polymerized coagulants (PACl). Polyaluminium silicate chloride has greater tolerance against pH variation than alum or PACl, whereas this novel coagulant works better at pH values between 7 and 9. Coagulation-flocculation has proved to be an efficient post-treatment method for the biologically pre-treated leachates, promoting the removal of the refractory humic substances, while the treatment efficiency of coagulation can be improved by the application of the new coagulant agent.     

Nitrogen removal via the nitrite pathway during wastewater co-treatment with ammonia-rich landfill leachates in a sequencing batch reactor

The biological treatment of ammonia-rich landfill leachates due to an inadequate C to N ratio requires expensive supplementation of carbon from an external carbon source. In an effort to reduce treatment costs, the objective of the study was to determine the feasibility of nitrogen removal via the nitrite pathway during landfill leachate co-treatment with municipal wastewater. Initially, the laboratory-scale sequencing batch reactor (SBR) was inoculated with nitrifying activated sludge and fed only raw municipal wastewater (RWW) during a start-up period of 9 weeks. Then, in the co-treatment period, consisting of the next 17 weeks, the system was fed a mixture of RWW and an increasing quantity of landfill leachates (from 1 to 10 % by volume). The results indicate that landfill leachate addition of up to 10 % (by volume) influenced the effluent quality, except for BOD₅. During the experiment, a positive correlation (r ²?=?0.908) between ammonia load in the influent and nitrite in the effluent was observed, suggesting that the second step of nitrification was partially inhibited. The partial nitrification (PN) was also confirmed by fluorescence in situ hybridisation (FISH) analysis of nitrifying bacteria. Nitrogen removal via the nitrite pathway was observed when the oxygen concentration ranged from 0.5 to 1.5 mg O₂/dm³ and free ammonia (FA) ranged from 2.01 to 35.86 mg N-NH₃/dm³ in the aerobic phase. Increasing ammonia load in wastewater influent was also correlated with an increasing amount of total nitrogen (TN) in the effluent, which suggested insufficient amounts of assimilable organic carbon to complete denitrification. Because nitrogen removal via the nitrite pathway is beneficial for carbon-limited and highly ammonia-loaded mixtures, obtaining PN can lead to a reduction in the external carbon source needed to support denitrification.