Municipal Solid Waste Landfill Leachate Research Articles

Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes.

In recent years, electrochemical advanced oxidation processes have been shown to be an effective alternative for the removal of refractory organic compounds from water. This study is focused on the effective removal of recalcitrant organic matter (micropollutants, humic substances, etc.) present in municipal solid waste landfill leachates. A mixture of eight landfill leachates has been studied by the electro-Fenton process using a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode or by the anodic oxidation process with a BDD anode. These processes exhibit great oxidation ability due to the in situ production of hydroxyl radicals ((•)OH), a highly powerful oxidizing species. Both electrochemical processes were shown to be efficient in the removal of dissolved total organic carbon (TOC) from landfill leachates. Regarding the electro-Fenton process, the replacement of the classical anode Pt by the anode BDD allows better performance in terms of dissolved TOC removal. The occurrence and removal yield of 19 polycyclic aromatic hydrocarbons, 15 volatile organic compounds, 7 alkylphenols, 7 polychlorobiphenyls, 5 organochlorine pesticides, and 2 polybrominated diphenyl ethers in landfill leachate were also investigated. Both electrochemical processes allow one to reach a quasicomplete removal (about 98%) of these organic micropollutants.

Perspective of harnessing energy from landfill leachate via microbial fuel cells: novel biofuels and electrogenic physiologies.

Organic carbon, nitrogen, and sulfur are highly concentrated in municipal solid waste (MSW) landfill leachate, which usually frustrates conventional leachate treatment technologies from the perspective of energy costs. Therefore, the possibility of converting leachate to a new energy source via microbial fuel cell (MFC) technology has been examined recently. This paper summarizes the power output and energy recovery efficiency of the leachate-fed MFCs according to different feeding patterns, cell structures, and loading rates. Also, we assess potential energy-generating chemicals in leachate like nitrogen and sulfur compounds and propose alternative pathways, which may lift strict ratios between organic carbon and nitrogen content in conventional denitrification of leachate and are expected to achieve a higher voltage than traditional organic-oxygen based cells. Although currently power output of leachate-fed MFCs is limited, it seems well possible that dynamic characteristics of MSW leachates and microbial physiologies underlying some bio-electrochemically efficient activities (e.g., direct interspecies electron transfer) could be stimulated in MFC systems to improve the present status.

Performance Assessment of Gravel–Tire Chips Mixes as Drainage Layer Materials Using Real Active MSW Landfill Leachate

Potential of clogging for rubber tire chips, gravel and their relative performance for transmitting high strength leachate when arranged in proportionate layers of relative thickness and in random state mixes of various percentage compared to the case of used alone were studied through column experiments. Comparative hydraulic performance of gravel and tire chips in their different combinations with percentage change (reduction) in COD, TSS, Ca-hardness and TDS concentration levels for the real active high strength MSW landfill leachate with time were investigated. Experiments were performed to simulate conditions occurring at the base of all active MSW landfills, in an attempt to replicate reasonably worst case conditions. Results clearly showed that the combinations ds (scrap tire chips layer thickness)/dg (gravel layer thickness) = 0.25, 0.50 (arranged by relative thickness) and Ws:Wg = 1:3 (25 % tire chips:75 % gravel; mixed by weight friction of each component) were good in term of obtaining initially relatively free drainage. Minor reduction in hydraulic conductivity for fairly longer duration, due to lesser clogging and small reduction in COD, TSS and Ca-hardness concentration levels were observed for these combinations. These experimental findings may prove to be very useful for the proper design, long term performance and service life of all tire chips–gravel made drainage layers of all the active MSW landfill leachate collection and removal systems.

Suggestion on the Leakage Pollution Control for the Historical Municipal Solid Waste Landfills in China

Artificial impermeable liner is the commonly used engineering technology method to prevent the Municipal Solid Waste (MSW) landfill leachate from polluting groundwater. The domestic and foreign researcher have discovered that the landfill impermeable liner was easy to have leaks during artificial liner laying down because of mechanical or the artificial mal-operation. The integrity test of impermeable liner for landfill began at the year of 2008. So a large number of historical landfill (construction completed before 2008) had become the pollution sources to local ecosystem because of the impermeable liner leakage. This article discussed the present situation of historical landfill leakage pollution, and propose technical and administrative measures to control those pollution in China.

Effect of organic fouling on micro-pollutant rejection in membrane bioreactor treating municipal solid waste landfill leachate.

Effect of membrane fouling on the removal of micro-pollutants from municipal solid waste landfill leachate, i.e. 4-methyl-2,6-di-tert-butylphenol (BHT), bisphenol A (BPA), and bis(2-ethylhexyl)phthalate (DEHP), in membrane bioreactor (MBR) was investigated. Modifications of membrane surface properties were analyzed to determine their relationship with their removals. Membrane fouling was simulated with foulants of different particle sizes on cellulose acetate (CA) microfiltration membrane to investigate the effect of foulant characteristics on BHT, BPA, and DEHP retention in the filtration experiment. The rejection efficiencies of the organic micro-pollutants in the MBR were 82-97% by fouled membrane, and 70-90% by cleaned membrane. The fouled membrane provided higher rejection of micro-pollutants from about 5% for BPA and BHT to 19% for DEHP. These improvements were due to the modification of membrane surface characteristics in terms of surface morphology, and contact angle after membrane fouling. The degree of rejection was found to be dependent upon the characteristics of foulant deposited on CA membrane surface. Increasing foulant particle size and its density shifted the mechanism of micro-pollutant rejection from membrane pore narrowing to pore blocking and cake formation while increasing pollutant adsorption capacity onto the foulant layer.

Evaluation of phytotoxicity of municipal landfill leachate before and after biological treatment.

In the present study, leachate toxicity of a municipal solid waste landfill located in the Sinos River Valley region (southern Brazil) was evaluated using plant bioassays. Leachate toxicity was assessed by analysis of seed germination and root elongation of lettuce (Lactuca sativa L.) and rocket plant Eruca sativa Mill.) and root elongation of onions Allium cepa L.). Bioassays were performed by exposing the seeds of L. sativa and E. sativa and the roots of A. cepa to raw leachate, treated leachate (biological treatment) and negative control (tap water). The levels of metals detected in both samples of leachate were low, and raw leachate showed high values for ammoniacal nitrogen and total Kjeldahl nitrogen. There is a reduction in the values of several physicochemical parameters, which demonstrates the efficiency of the treatment. Both L. sativa and A. cepa showed a phytotoxic response to landfill leachate, showing reduced root elongation. However, the responses of these two plant species were different. Root elongation was significantly lower in A. cepa exposed to treated leachate, when compared to negative control, but did not show any difference when compared to raw leachate. In L. sativa, seeds exposed to the raw leachate showed significant reduction in root elongation, when compared to treated leachate and negative control. Seed germination showed no difference across the treatments. The results of the study show that plant species respond differently and that municipal solid waste landfill leachate show phytotoxicity, even after biological treatment.

Scaling of ammonia stripping towers in the treatment of groundwater polluted by municipal solid waste landfill leachate: study of the causes of scaling and its effects on stripping performance

This paper documents the causes of the scaling of stripping towers used for the treatment of groundwater polluted by the leachate from an old municipal solid waste (MSW) landfill in northern Italy. The effects of the scaling on the stripping performance are also reported. The whole process consists of a coagulation-flocculation pre-treatment at pH > 11, followed by an ammonia stripping stage, after heating the water to 38°C in order to improve removal efficiency. The stripped ammonia is recovered by absorption with sulfuric acid, producing a 30% solution of ammonium sulfate (reused as a base fertilizer). The effluent air stream is recirculated to the stripping towers (closed loop systems) in order to avoid an excessive temperature drop inside the packings, mainly in winter, with consequent loss of efficiency and risk of icing. The progressive scaling of the packing has resulted in a loss of ammonia removal efficiency from an initial value of 98% (clean packing) down to 80% after six months of continuous operation, necessitating a chemical cleaning. Optimum conditions for design and operation of the stripping process are also documented.

Relationships between antibiotics and antibiotic resistance gene levels in municipal solid waste leachates in Shanghai, China.

Many studies have quantified antibiotics and antibiotic resistance gene (ARG) levels in soils, surface waters, and waste treatment plants (WTPs). However, similar work on municipal solid waste (MSW) landfill leachates is limited, which is concerning because antibiotics disposal is often in the MSW stream. Here we quantified 20 sulfonamide (SA), quinolone (FQ), tetracycline (TC), macrolide (ML), and chloramphenicol (CP) antibiotics, and six ARGs (sul1, sul2, tetQ, tetM, ermB, and mefA) in MSW leachates from two Shanghai transfer stations (TS; sites Hulin (HL) and Xupu (XP)) and one landfill reservoir (LR) in April and July 2014. Antibiotic levels were higher in TS than LR leachates (985 ± 1965 ng/L vs 345 ± 932 ng/L, n = 40), which was because of very high levels in the HL leachates (averaging at 1676 ± 5175 ng/L, n = 40). The mean MLs (3561 ± 8377 ng/L, n = 12), FQs (975 ± 1608 ng/L, n = 24), and SAs (402 ± 704 ng/L, n = 42) classes of antibiotics were highest across all samples. ARGs were detected in all leachate samples with normalized sul2 and ermB levels being especially elevated (-1.37 ± 1.2 and -1.76 ± 1.6 log (copies/16S-rDNA), respectively). However, ARG abundances did not correlate with detected antibiotic levels, except for tetW and tetQ with TC levels (r = 0.88 and 0.81, respectively). In contrast, most measured ARGs did significantly correlate with heavy metal levels (p < 0.05), especially with Cd and Cr. This study shows high levels of ARGs and antibiotics can prevail in MSW leachates and landfills may be an underappreciated as a source of antibiotics and ARGs to the environment.

Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H₂O₂ for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry.

This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS). Three variables (pH, irradiation time and buffer concentration) were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v) were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1) were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

Toxicity Assessment of Municipal Solid Waste Landfill Leachate Collected in Different Seasons from Okhala Landfill Site of Delhi

Recent studies of leachate induced toxicity have mainly focused on crude leachates collected once from the landfill site, while little attention has been paid to the changes in toxicity resulting from the varying leachate concentration with respect to seasonal variation. The present study deals with the toxicological effects of municipal landfill leachate on Vicia faba. Leachate samples were collected in different seasons (summer, monsoon and winter) and toxicity study was performed via various parameters like germination inhibition, growth, chlorophyll content, lipid peroxidation and activities of antioxidant enzymes. The results show that landfill leachate of all three seasons promoted the growth and chlorophyll content at lower doses for short exposure time but at the higher doses there was inhibition of growth as well as reduction in the chlorophyll content. There was a dose dependent elevation in the malondialdehyde (MDA) level and inhibited antioxidant enzyme activities. The physiological responses varied as a function of leachate concentration which was further dependent on the season of leachate collection. Therefore, this study suggests that the leachate collected in all the three seasons is toxic and may pose a health effect to the general public directly or indirectly. It also suggests that the most important aspect for the treatment of landfill leachate is controlling its concentration which varies with respect to the seasons of leachate collection.

An integrated approach combining chemical analysis and an in vivo bioassay to assess the estrogenic potency of a municipal solid waste landfill leachate in Qingdao.

Various adverse effects related to landfill leachate have made leachates an important issue in past decades, and it has been demonstrated that landfill leachate is an important source of environmental estrogens. In this study, we employed chemical analysis of some already evaluated estrogenic substances, in combination with a bioassay using several specific biomarkers (e.g., plasma vitellogenin and sex steroids, enzyme activity of gonad gamma-glutamyl transpeptidase, and gonadosomatic index) to evaluate the estrogenic activities in outlets from different stages of the leachate treatment process. The results indicated that 5 environmental estrogens (4-t-octylphenol, bisphenol A, di-ethyl phthalate, di-n-butyl phthalate, and diethylhexyl phthalate) were detected by a gas chromatography-mass spectrometry, and the concentrations in leachate samples were 6153 ng/L, 3642 ng/L, 2139 ng/L, 5900 ng/L, and 9422 ng/L, respectively. Leachate (1∶200 diluted) induced the synthesis of plasma vitellogenin and led to decreased enzyme activity of gonad gamma-glutamyl transpeptidase and gonadosomatic index in male goldfish (Carassius auratus) after a 28-day exposure, while increased circulating 17β-estradiol level was also observed in males exposed to treated effluent. Although the target EEs were partially removed with removal rates varying from 87.2% to 99.77% by the “membrane bioreactor+reverse osmosis+aeration zeolite biofilter” treatment process, the treated effluent is still estrogenic to fish. The method combined chemical techniques with the responses of test organisms allowing us to identify the group of estrogen-like chemicals so that we were able to evaluate the overall estrogenic effects of a complex mixture, avoiding false negative assessments.

Influence of Compact Clay Layer on the Seepage Performance of the Municipal Solid Waste Landfills

The pollutants in the municipal solid waste landfill leachate result in severe damage to the environment of the groundwater and the soil beneath the municipal solid waste landfill. The liner systems with a low leakage performance are commonlly adopted under the municipal solid waste landfills to stop the contaminants of the leachate from polluting the environment. Even there are the rigorous demands in related specifications for the design of the liner system in the landfill. Pollution of the groundwater and the soil beneath the landfill still occurred in a large number of rubbish landfills because of the seepage. To investigate the influence of the compact clay layer (CCL) on the seepage performance of the liner systems, parametric analyses are conducted to study the influence of the thickness of CCL and the hydraulic conductivity of CCL on the leakage performance of the liner system. In conclusion, some suggestions for the design of the municipal solid waste landfills are proposed based on the analyses results.

Fate and transport of pollutants through a municipal solid waste landfill leachate in Sri Lanka

This study focuses on the characterization of leachate generated from Gohagoda dumpsite in Kandy, Sri Lanka, assessment of its spatial and temporal variations, and identification of subsurface canals and perched water bodies in the wetland system affected by the leachate flow. Leachate samples were collected monthly throughout dry and rainy seasons from different points of the leachate drainage channel over a period of 1 year and they were tested for quality parameters: pH, temperature, electrical conductivity, total dissolved soils, alkalinity, hardness, total solids, volatile solids, total suspended solids, volatile suspended solids, biochemical oxygen demand (BOD5), chemical oxygen demand, nitrate-nitrogen, nitrite-nitrogen, phosphates, ammonium-nitrogen, chloride, dissolved organic carbon, total organic carbon and heavy metals. Sequential soil extraction procedures were performed for the characterization of leachate-affected local soil. A geophysical survey using direct current resistivity technique was conducted at locations downstream of the dumpsite. Leachate characteristics indicated that the leachate is in the methanogenic phase and the results strongly suggest that the leachate may be polluting the river where the leachate is discharged directly. Leachate exceeds the allowable limits of Sri Lankan wastewater discharge standards for many of the parameters. Significant difference (P < 0.05) was observed for most of organic and inorganic parameters among all sampling locations. Many parameters showed a negative correlation with pH. The affected soils showed high heavy metal concentrations. Resistivity study confirmed a confined leachate flow at the near surface with few subsurface canals. However, no separate subsurface plume movement was observed. The results of this research can effectively be used for the establishment of an efficient and effective treatment method for the Gohagoda landfill leachate.

Experimental plant for the physical-chemical treatment of groundwater polluted by Municipal Solid Waste (MSW) leachate, with ammonia recovery

The paper documents the results of the experimental treatment of groundwater (flow rate: 300 m 3 h -1 ) polluted by the leachate of an old MSW landfill (7 million tonnes) in northern Italy. The process consists of a coagulation-flocculation pre-treatment at pH > 11, and subsequent ammonia stripping, after heating the water to 35-38 °C by means of the biogas produced by the landfill. The stripped ammonia was recovered by absorption with sulfuric acid, producing a 30% solution of ammonium sulfate, which was reused as a base fertilizer. In addition, the paper reports important operational aspects related to the scaling of the stripping tower’s packing and its effect on pH and temperature profiles inside the towers caused by the closed loop, which recirculates the stripping air coming from the ammonia absorption towers with sulfuric acid. The average removal efficiency of ammonia reached 95.4% with an inlet mean concentration of 199.0 mg L -1 .

English

The purpose of this research paper was to review the different molecular biology techniques that are used in landfill investigations. The methods discussed include polymerase chain reaction (PCR), fluorescent&nbsp;in situ&nbsp;hybridization (FISH) and phospholipid fatty acid analysis (PLFA). Operation of landfills as bioreactors is now becoming a common practice, which involves the identification of different microbiological activities that facilitate the eventual breakdown of landfill wastes into useful and innocuous materials. In this review, the two important microbial activities that are discussed include methanotrophic process, carried out by methanotrophic bacteria, and methanogenic processes, carried out by methanogenic bacteria. Other bacteria encountered in landfills such as&nbsp;Nitrosospira&nbsp;and&nbsp;Nitrosomonas&nbsp;are also briefly discussed. As the name of these processes imply, methane oxidation and methane production by these microbial activities in landfills constitute another main focus of this paper. The application of these molecular biological techniques in real-time has also been demonstrated in studies involving the investigation of methanogenic diversity and activity in municipal solid waste landfill leachates and this is also discussed further. The results and conclusions of different research studies that focused on these techniques are hereby identified, discussed and summarized. &nbsp; Key words:&nbsp;Bioreactors, polymerase chain reaction (PCR),&nbsp;fluorescent&nbsp;in situ&nbsp;hybridization (FISH), phospholipid fatty acid analysis (PLFA), methanogens, methanotrophs, landfilling.

Landfill leachate – a water and nutrient resource for algae-based biofuels

There is a pressing need for sustainable renewable fuels that do not negatively impact food and water resources. Algae have great potential for the production of renewable biofuels but require significant water and fertilizer resources for large-scale production. Municipal solid waste (MSW) landfill leachate (LL) was evaluated as a cultivation medium to reduce both water and elemental fertilizer demands of algae cultivation. Daily growth rate and cell yield of two isolated species of algae (Scenedesmus cf. rubescens and Chlorella cf. ellipsoidea) were cultivated in MSW LL and compared with Bold's Basal Medium (BBM). Results suggest that LL can be used as a nutrient resource and medium for the cultivation of algae biomass. S. cf. rubescens grew well in 100% LL, when pH was regulated, with a mean growth rate and cell yield 91.2% and 92.8% of those observed in BBM, respectively. S. cf. rubescens was more adaptable than C. cf. ellipsoidea to the LL tested. The LL used in this study supported a maximum volumetric productivity of 0.55 g/L/day of S. cf. rubescens biomass. The leachate had sufficient nitrogen to supply 17.8 g/L of algae biomass, but was limited by total phosphorus. Cultivation of algae on LL offsets both water and fertilizer consumption, reducing the environmental footprint and increasing the potential sustainability of algae-based biofuels.

Pollution Pathways of Pharmaceutical Residues in the Aquatic Environment on the Island of Mallorca, Spain

This work determines the principal environmental pollution pathways of pharmaceuticals on the island of Mallorca (Spain). The evaluation was made on the basis of the quantification of pharmaceutical residues by liquid chromatography-tandem mass spectrometry in several environmental water samples, including wastewater-treatment plant effluents, municipal solid waste landfill leachates, groundwater (GW), and marine water. An overall set of 19 pharmaceuticals has been identified in the environment of the 27 human pharmaceuticals investigated in this study. WWTP effluents are the main source of discharge of the pharmaceuticals into the aquatic environment. The data indicate that reuse of treated domestic wastewater for irrigation (which supplies some 30% of the total water demand in Mallorca) contributes to the contamination of GW. In addition, leaching from landfills is identified as another, but minor, possible source of introduction of pharmaceuticals to GW aquifers. Finally, WWTP effluents ending in the Mediterranean Sea, primarily highly urbanized coastal areas, cause pharmaceutical residues to occur in marine water bodies.

Application of iron nanaoparticles in landfill leachate treatment - case study: Hamadan landfill leachate

This study was performed with the objective of determining the efficiency of iron nanoparticles for reducing chemical oxygen demand (COD), 5-day biological oxygen demand (BOD5), total solids (TS) and color of Hamadan city landfill leachate. Experiments were performed in a batch reactor and the main effective factors of pH, reaction time and concentration of iron nanoparticles were investigated. The obtained data were analyzed with One-Way ANOVA statistical test and SPSS-13 software. Maximum removal efficiencies were 47.94%, 35%, 55.62% and 76.66% for COD, BOD5, TS and color, respectively (for 2.5 g/L iron nanoparticles dosage, pH = 6.5 and 10 min reaction time). The results showed that the removal of COD, BOD5 and color had reverse relationship with contact time and TS removal followed a direct relationship (P < 0.05). Iron nanoparticles could remove averagely 53% of leachate COD, BOD5, TS and color in a short contact time (10 min) increasing pH up to 6.5, increased the removal efficiency for COD, BOD5, TS and color and then removal efficiency decreased with increasing pH to 8.5. Increasing the dosage of nanoparticles to 2.5 g/L increased the efficiency of process. High compatibility and efficiency of this process was proven by landfill leachate pre-treatment or post-treatment, so this removal method may be recommended for municipal solid waste landfill leachate treatment plants.

Laboratory study on the leaching potential of spent alkaline batteries using a MSW landfill leachate

Two leaching tests were carried out, one with whole batteries and another with cross-cut batteries. In both cases, NEN 7343 (a Nederland’s Standard) procedure was followed using a municipal solid waste (MSW) landfill leachate as extraction solution. Seven fractions were collected corresponding to cumulative liquid/solid (L/S) ratio from 0.1 to 10.0. Those fractions were separately characterized in terms of pH, conductivity, redox potential, density, sulphate, chloride, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn. Results showed that the influence of the alkaline batteries in the landfill leachate composition varies with their physical integrity and with the L/S ratio, and several variations were observed throughout the tests. The leachate pH and redox potential increased as result of the contact with batteries, particularly pH in the test with the cross-cut batteries. The leachate density and conductivity did not change significantly with the whole batteries, in contrast with the test with cross-cut batteries.

Modeling of Leachate Characteristics and Clogging of Gravel Drainage Mesocosms Permeated with Landfill Leachate

AbstractA two-dimensional numerical model, BioClog, is used to estimate the leachate characteristics and leachate-induced clogging of laboratory mesocosms permeated with real municipal solid waste landfill leachate. The model is used to examine mesocosms with 38-mm (nominal diameter) gravel subjected to different durations of leachate permeation, mesocosms run-in series, and mesocosms with 19-mm gravel. A comparison of the calculated and measured leachate concentrations indicates that the model provided reasonable predictions of the effluent chemical oxygen demand (COD) and calcium concentrations. The calculated porosities within the saturated drainage layers are general in encouraging agreement with the measured values from all experimental mesocosms. The calculated and measured hydraulic conductivities are in reasonable agreement. The modeling results indicated that reducing the mass loading for the drainage layers and increasing the particle size of granular media can be expected to extend the time bef...