Organic Compounds In Leachate Research Articles

Weathering alters the profile of trace metals and organic compounds in leachates and bioavailability extracts from microplastics of trail running shoes

Microplastics (MPs) from rubber outsoles of trail running shoes may contribute significantly to contamination in protected areas. In the natural environment, weathering processes can damage MP molecular structure and alter the mobility of inorganic and organic compounds used as additives in rubber. In this study, we characterised changes in the surface morphology, functional groups, and thermal stability of MPs weathered on and below the soil surface over 12 weeks, and analysed inorganic and organic additives in leachates (0.01M CaCl2) and bioaccessibility extracts (ethyl acetate). Weathering conditions included UVC irradiation at 25 °C and 80% soil moisture. Microplastics on the soil surface exhibited cracking, fragmentation, and increased extractability of zinc, sulphur, titanium and fatty acids. Microplastics below the soil surface were not significantly physically or chemically altered, however zinc leachability increased following extended weathering by up to 155%. Bioaccessibility of thiol, aromatic and cyclic organic additives decreased from both surface and sub-surface MPs over the 12 week weathering period, but there was evidence of an increase in transformation by-products. Microplastic toxicity may be significantly altered by environmental conditions and MP weathering. It is critical ecotoxicological studies use weathered MPs to assess impacts on rare and endemic species found in protected spaces.

Adsorption of Organic Compounds in Leachate using Precipitated Calcium Carbonate (PCC) from Ale-Ale Shells

Leachate waste from piles of garbage in the landfill (TPA) has a high concentration of Chemical Oxygen Demand (COD). High COD concentrations can cause a decrease in dissolved oxygen concentrations in the waters. Simple leachate treatment is carried out using the adsorption method with adsorbents derived from food waste. This research used Precipitated Calcium Carbonate (PCC) adsorbent from ale-ale shells. This study aims to evaluate the effect of particle size and calcination temperature variations on PCC yield and analyze the adsorption ability of PCC adsorbents in reducing COD concentrations. In addition, PCC was characterized using an infrared spectrophotometer (FTIR) and an X-ray diffractometer (XRD). Determination of COD concentration was carried out by permanganometric titration. The optimum PCC yield of 57.75% was obtained from Ale-ale shells with a particle size of 40 mesh with a calcination temperature of 800 ° C. The functional groups in PCC are C-O at wave numbers 1403 cm -1 , 873 cm -1 , and 713 cm -1 . XRD characterization showed the presence of a calcite phase with a high peak intensity at 2 = 29.38 ° . The adsorption of organic matter on leachate by PCC (4.5 g/50 mL) with a stirring speed of 200 rpm for 240 minutes reduced the COD concentration of leachate from 1131.28 mg/L to 456.94 mg/L with an adsorption efficiency of 59.61% .

Characterizing volatile organic compounds in leachate from Gohagoda municipal solid waste dumpsite, Sri Lanka

Fate and transport of volatile organic compounds (VOCs) in landfill leachate causes environmental pollution and human health concern. These VOCs can directly be emitted to the atmosphere and also can end up in leachate plume from open solid waste dumpsites. However, no data exists on the VOCs in landfill leachate in Sri Lanka. Hence, the purpose of this study was to assess the variation of VOCs in landfill leachate at the Gohagoda Municipal Solid Waste (MSW) dumpsite, Kandy, Sri Lanka in a dry (Spring) and a wet (Autumn) month. A list of the key offensive VOCs covering 13 chemicals in leachate was quantified by using a head space–gas-chromatography–mass-spectrometry (HS-GC–MS). Results indicated that benzene and toluene were most commonly observed in both sampling periods, ranging from 1.78–21.7 and 1.73–20.2µgL−1, respectively. 4-Isopropyltoluene had the highest concentrations of the VOCs investigated in both sampling periods (38.0 and 129µgL−1 in spring and autumn, respectively). Totally, 9 different VOCs out of 13 listed were detected in the landfill leachate. In comparison, the number of VOCs and total VOC concentrations were higher at all sampling locations in spring except GSV1 sampling point. Thereby, it appears that a time series analysis of VOCs during the dry and wet months may provide a better understanding of the degree and risk of pollution of the Mahaweli River water.

IDENTIFICATION OF ORGANIC COMPOUNDS IN A MUNICIPAL LANDFILL LEACHATE BY GAS CHROMATOGRAPHY COUPLED WITH MASS SPECTROMETRY

The organic compounds present in leachate can contaminate soil, superficial and underground water, and the majority is considered harmful to the environment and human health. The objective of this study was to identify organic compounds present in landfill leachate located in Maringa-PR by gas chromatography coupled to mass spectrometry (GC-MS). The raw leachate was characterized by measurements of pH, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOQ), Dissolved Organic Carbon (DOC), apparent and true colors, turbidity and absorbance at 254 nm. The extraction of organic compounds in leachate was carried out by liquid-liquid extraction (LLE) with ethyl acetate and dichloromethane solvents, while varying the pH and ionic strength. The analysis of the leachate by GC-MS showed the presence of compounds considered to have toxic effects on the environment and human health, such as pesticides and phenolic compounds. Several compounds containing oxygenated groups such as carboxylic acids and alcohols were also identified, indicating that it was highly probable that the decomposition of waste in the landfill was in the acidogenic phase.

Mineral and organic compounds in leachate from landfill with concentrate recirculation.

The effect of a reverse osmosis concentrate recirculation on the mineral and organic compounds in a landfill leachate was investigated. Investigated was the quality of a leachate from two landfills operated for different periods (a 20-year-old Cell A and a 1-year-old Cell B), where the concentrate was recirculated. Examined were general parameters (conductivity, pH), organic compounds (biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic nitrogen, BOD/COD), and inorganic compounds (nitrogen ammonia, sulfite, sulfate, cyanide, boron, chloride, ferrous, zinc, chrome, copper). The findings from the first year of investigation showed that over the initial period of recirculation, the concentration of organic compounds (BOD, COD) increased, but after 6 months their values stabilized. It indicates that the concentrate recirculation accelerated organic decomposition, especially in the new landfill Cell. The analysis of inorganic parameters showed that recirculation landfills produce a leachate with a higher concentration of N-NH4, and Cl(-). In case of the old landfill Cell, an increase in B and Fe was also noticeable. These compounds are cyclically washed out from a waste dump and require an additional pretreatment in order to exclude them from recirculation cycle. The increased concentration of Cu, Zn, and Fe was noticed during the initial months of recirculation and in the season of intense atmospheric precipitation in the leachate from both Cells. Higher values of electro conductivity, Cl(-), N-NH4 (+), B, and Fe in the leachate from the old field indicate that the attenuation capacity of this landfill is close to exhaustion.

Characterisation of the recalcitrant organic compounds in leachates formed during the anaerobic biodegradation of waste

This study investigates the use of UV absorption and fluorescence spectroscopy to assess the early development of recalcitrant organic compounds in leachates formed during the anaerobic biodegradation of municipal solid waste. Biochemical methane potential tests were carried out on fresh waste (FW) and composted waste (CW) over a period of 150 days and leachates produced from the degradation of two wastes were analysed for humic-like (H-L) and fulvic-like (F-L) structures by UV spectroscopy and fluorescence excitation-emission-matrix analyses. During anaerobic biodegradation, the synthesis and utilization of H-L and F-L structures in the leachates over time was indicative of the generation of the recalcitrant organic compounds. The results obtained from UV absorption and fluorescence spectroscopy suggested that CW leachates resulted in a higher concentration and more condensed form of recalcitrant H-L and F-L molecules than FW leachates. These findings demonstrate how fluorescence and UV absorption spectroscopy can be used as an indicator for monitoring the evolution of recalcitrant organic compounds (H-L and F-L substances) in leachates formed at different stages of waste biodegradation.

Advanced Oxidation Processes (AOPs) for reduction of organic pollutants in landfill leachate: a review

Uncontrolled municipal landfill leachate during landfilling can seriously pollute groundwater, surface water and soil. Over the past decades, a variety of Advanced Oxidation Processes (AOPs), primarily utilising hydroxyl radicals to effect water purification, have been frequently investigated for treatment of landfill leachate. This paper first summarises the typical characteristics of organic compounds in leachate, and then reviews the AOPs applied for leachate treatment, including O3-based, UV-based, Fenton-based, and two emerging (ultrasound irradiation and electronic-beam irradiation) AOPs. Finally, some issues in advanced oxidation treatment of landfill leachate are briefly remarked.

FLUORESCENCE EVOLUTION OF LEACHATES DURING TREATMENT PROCESSES FROM TWO CONTRASTING LANDFILLS

Landfill leachates are composed of a complex mixture of organic matter, including a wide range of potentially fluorescent organic compounds. The fluorescence excitation–emission matrix (FEEM) of leachates during treatment processes is investigated. Particular attention is paid to the fluorescence evolution of leachates during treatment processes. Two typical types of landfill, landfill A (a direct municipal solid waste (MSW) landfill) and landfill B (disposal of bottom ashes from MSW incinerators), in a city in Southern China were selected. The results show that two characteristic and intense excitation–emission peaks located at Ex/Em = 310–330 nm/395–410 nm (peak α) and Ex/Em = 250–260 nm/450–460 nm (peak α′) are observed. As the aromatic chemicals, capable of emitting fluorescence, are more recalcitrant to biodegradation than aliphatic chemicals, enhancement of the dissolved organic carbon normalized fluorescence intensities is demonstrated during treatment processes of leachate A and leachate B. This is confirmed by the variation of ultraviolet absorptivity of leachates at 254 nm. Peak α′ and peak α are attributed to a mixture of xenobiotic organic compounds with low molecular weight and relatively stable aromatic fulvic‐like matters with high molecular weight, respectively. Humic substances are more resistant to biodegradation than xenobiotic organic compounds, so a significant reduction in the Iα′ /Iα values (fluorescence intensity ratios of peak α′ and peak α) of leachate A was observed during treatment processes. However, no evident variation for the Iα′ /Iα values of leachate B was found during treatment processes owing to the low concentrations of xenobiotic organic compounds in leachate B after incineration.

Characterization of the Leachate in an Urban Landfill by Physicochemical Analysis and Solid Phase Microextraction-GC/MS

The aim of this study is to evaluate extensively the characterization and identification of major pollutant parameters by paying attention to the organic chemical pollution for unregulated dumping site leachate in Eskişehir/Turkey. The study that is first and only one research has been very important data related with before new sanitary landfill site in Eskişehir city. For this purpose, in this study leachate samples were collected in-situ at monthly interval for a period of 8 months. Firstly, thirty three physicochemical parameters were monitored. Secondly, SPME technique was used for identification of organic pollutants. Meteorological data were also recorded for the same sampling period to correlate meteorological data and physicochemical parameters. Mean values are used in the correlation analysis. Correlation is shown only for the relationship between air temperature and NO(3) (-). No correlation has been found between rain and leachate quality parameters since the amount of rain was very low during the sampling period. However, analysis results were generally decreased in winter season when each parameter and each sampling point are examined separately. According to correlation between every parameter, especially solid content and dissolved oxygen concentration of leachate is affecting to other parameters. Also, sodium and potassium are changing proportionally with same parameters (suspended solids, fixed solids, dissolved oxygen) and high correlation between chloride and heavy metal concentration is showing. The results were statistically evaluated by use of SPSS 10.0 program. Second part of the study, the leachate was extracted by Solid Phase Microextraction (SPME) technique and then analyzed. Of the methodologies tested in this study, the best one selected was based on 100 micro m polydimethylsiloxane coated fiber (PDMS), headspace with heating (Delta HS) sampling mode and an extraction time of 15 min. at a temperature of 50 degrees C. Thirty three organic compounds in leachate were identified by GC/MS.

Organic compounds in re-circulated leachates of aerobic biological treated municipal solid waste

Biodegradation of organic matter is required to reduce the potential of municipal solid waste for producing gaseous emissions and leaching contaminants. Therefore, we studied leachates of an aerobic-treated waste from municipal solids and a sewage sludge mixture that were re-circulated to decrease the concentration of biodegradable organic matter in laboratory-scale reactors. After 12 months, the total organic C and biological and chemical oxygen demands were reduced, indicating the biodegradation of organic compounds in the leachates. Curie-point pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and pyrolysis-field ionization mass spectrometry (Py-FIMS) revealed that phenols, alkylaromatic compounds, N-containing compounds and carbohydrates were the predominate compounds in the leachates and solid waste. Leachate re-circulation led to a higher thermal stability of the residual organic matter as indicated by temperature-resolved Py-FIMS. Admixture of sewage sludge to solid waste was less effective in removing organic compounds from the leachates. It resulted in drastic higher and more bio-resistant loads of organic matter in the leachates and revealed increased proportions of alkylaromatic compounds. The biodegradation of organic matter in leachates, re-circulated through municipal solid waste, offers the potential for improved aerobic waste treatments and should be investigated on a larger scale.

Xenobiotic organic compounds in leachates from ten Danish MSW landfills--chemical analysis and toxicity tests.

A monitoring program comprising chemical analysis and biological toxicity testing of leachate samples from 10 Danish landfills (six engineered and four uncontrolled) revealed the presence of 55 different xenobiotic organic compounds (XOCs) and 10 degradation products of XOCs. The compounds belong to the following groups: BTEX, C3-benzenes, bicyclo compounds, napthalenes, chlorinated aliphatics, phenols (chloro-, methyl-, dimethyl, nonyl-), pesticides, and phthalates. Concentrations of single XOCs ranged from <0.1 to 2220 microg/L. A pesticide screening including 101 different compounds resulted in detection of 18 pesticides and three degradation products. The findings of degradation products of toluene, phenols, phthalates, pesticides, and nonylphenol ethoxylates show that degradation occurred inside the landfills. In biotests with bacteria and algae it was found that the non-volatile organic compounds were toxic as the samples only needed to be pre-concentrated from 1.3 to 9.4 times to give 50% inhibition of the test organisms. One of the ten samples proved to be genotoxic in the umuC test after 141 times pre-concentration. A major part of the organic chemicals causing toxicity remains unknown and it is recommended to combine chemical analyses and biotests in future monitoring programs.

Leaching of organic contaminants from storage of reclaimed asphalt pavement

Recycling of asphalt has been promoted by rapid increases in both the use and price of petroleum‐based bitumen. Semi‐volatile organic compounds in leachates from reclaimed asphalt pavement, measured in field samples and in laboratory column test, were analysed through a GC/MS screen‐test methodology. Sixteen PAH (polyaromatic hydrocarbons) were also analysed in leachates from the column study. The highest concentrations of semi‐volatile compounds, ‐ 400 μg 1‐1, were measured in field samples from the scarified stockpile. Naphthalene, butylated hydroxytoluene (BHT) and dibutyl phthalate (DBP) were the most dominant of the identified semi‐volatiles. The occurrence of these compounds in urban groundwater, also indicate high emission rates and persistent structures of the compounds, making them potentially hazardous. Car exhausts, rubber tires and the asphalt material itself are all probable emission sources, determined from the organic contaminants released from the stockpiles. The major leaching mechanism indicated was dissolution of organic contaminants from the surface of the asphalt gravels. In the laboratory column test, the release of high‐molecular weight and more toxic PAH was higher in the leachates after two years than at the commencement of storage. The concentrations of semi‐volatiles in leachates, were also several times lower than those from the field stockpile. These results demonstrate the need to follow up laboratory column test with real field measurements.

MODIFICATION OF COAGULATION AND FENTON OXIDATION PROCESSES FOR COST-EFFECTIVE LEACHATE TREATMENT

Physicochemical processes have been used to remove nonbiodegradable organic compounds in leachate generated from sanitary landfills. In this study, a coagulation process combined with Fenton oxidation was evaluated for the removal of refractory organics in leachate. Recycling of sludge generated from Fenton oxidation to a coagulation process was attempted to reduce operation cost and to improve organic removal rate. The addition mode of Fenton reagent was also modified to obtain a better organic removal rate and more cost-effective operation. With Fenton sludge recycling, 9% higher COD removal was obtained, and the sludge to be disposed could be reduced up to 50%. Also, the coagulant could be reduced by 50%. For Fenton oxidation process, stepwise addition of reagents gave a 5% higher COD removal, and a 25% reduction in chemical consumption.

Application of headspace analysis and AOX-measurement to leachate from hazardous waste landfills

The applicability of headspace analysis for the quantitation of volatile organic compounds in leachates from hazardous waste landfills is investigated with respect to standard stability, leachate stability and reproducibility. Between the corresponding data sets, deviations at about 10 % are observed. Besides the analysis of the volatile leachate components, the sum parameters POX and AOX are determined for the leachate samples. From the POX-data, good agreements with the total organic chlorine determined by headspace analysis are received. For determination of AOX, two different methods are applied to the leachates and discussed with respect to the high concentrations of POX determined in all leachate samples.

Chemical Characterization of Organic Compounds in Leachates from Surface-Retorted Oil Shale Generated by Gas Combustion and Indirect Pyrolysis

Abstract Chemical characterization of leachates from surface-retorted oil shale generated by gas combustion (Paraho process) and indirectly-heated pyrolysis (TOSCO II process) revealed the presence of several classes of organic acids. Paraho leachates contained various oxygenated species, such as aliphatic monocarboxylic acids (C5-C8), dicarboxylic acids (C8-C11), and arenecarboxylic acids, with benzoic acid as the major component. A series of methyl-substituted arenecarboxylic acids were identified in the TOSCO leachate, with 3,5-dimethylbenzoic acid as the major component. Differences in chemical composition of the two leachates can be explained in terms of the different processes used to generate the two types of spent shale. Arenecarboxylic acids in both leachates were quantitatively determined. The potential exists for leaching of these oxygenated species from spent shale.

Identification of organic compounds in leachate from a waste tip

Two different types of leachate from a municipal waste tip have been analyzed. The first type of leachate was collected from a waste tip in the acidification stage. The organic load of this leachate was high and consisted mainly of free volatile acids (over 95% of the TOC). Volatile amines and ethanol were also present (0.8 and 0.7% of the TOC respectively). The leachate was extracted with hexane and the extract was analyzed with infrared and nuclear magnetic resonance spectroscopy and a gas chromatograph-mass spectrometer combination. In the extract alcohols, hydrocarbons, esters, terpenes and phthalates have been identified. High molecular weight compounds were present only in a low concentration. The second type of leachate was collected from a waste tip in the methane fermentation stage. The organic load was relatively low. An important part of the organics was identified as high molecular weight compounds. About 32% of the organic carbon consisted of compounds with a molecular weight over 1000. Acids, amines and alcohols could not be detected. This means that the organic compounds present were end products of degradation processes. Furthermore there was a remarkable difference in heavy metal content between the two types of leachate.