Size-fractionation and characterization of landfill leachate and the improvement of Cu2+ adsorption capacity in soil and aged refuse

Leachate was collected from an anaerobic lagoon at Shanghai Laogang refuse landfill, the largest landfill in China, and the sample was separated into six fractions using micro-filtration membranes, followed by ultra-filtration membranes. Several parameters of the samples were measured, including chemical oxygen demand (COD), total organic carbon (TOC), total solids (TS), pH, total phosphate (TP), total nitrogen (TN), fixed solids (FS), NH4+, orthophosphate, color, turbidity, and conductivity. These parameters were then quantitatively correlated with the molecular weight cutoff of the membrane used. Organic matter in the dissolved fraction (MW<1kDa) predominated in the leachate, accounting for 65% of TOC. Thermal infrared spectroscopy was used to characterize the filter residues. Asymmetric and symmetric stretching of methyl and methylene groups, and of functional groups containing nitrogen and oxygen atoms, were observed. In addition, the ability of two different samples to adsorb heavy metals was tested. Cu2+ was chosen as the representative heavy metal in this study, and the samples were soil; aged refuse, which had spent 8 years in a conventional sanitary landfill; and samples of soil and aged refuse treated for 48h with leachate in the ratio of 5g of sample per 50ml of leachate. Cu2+ uptake by the raw soil was approximately 4.60microg/g, while uptake by the leachate-contacted soil and leachate-contacted aged refuse were 5.66 and 5.11microg/g, respectively. These results show that the organic matter in the leachate enhanced the capacity of aqueous solutions to adsorb Cu2+.     

Movement of unlined landfill under preloading surcharge

As organic solid waste is decomposed in a landfill and mass is lost due to gas and leachate formation, the landfill settles. Settlement of a landfill interferes with the rehabilitation and subsequent use of the landfill site after closure. This study examined the soil/solid waste movement at the Al-Qurain landfill in Kuwait after 15 years of closure as plans are underway for redevelopment of the landfill site that occupies about a km(2) with an average depth of 8-15m. Field experiments were conducted for 6 mo to measure soil/solid waste movement and water behavior within the landfill using two settlement plates with a level survey access, Casagrande-type piezometers, pneumatic piezometers, and magnetic probe extensometers. Previous results obtained indicated that biological decomposition of refuse continued after closure of the landfill site. The subsurface water rise enhanced the biological activities, which resulted in the production of increasing quantities of landfill gas. The refuse fill materials recorded a high movement rate under the imposed preloading as a result of an increase in the stress state. Up to 55% of the total movement was observed during the first 2 weeks of fill placement and increased to 80% within the first month of the 6-mo preloading test. Pneumatic piezometers showed an increase in water head, which is attributed to the developed pressure of gases escaping during the preloading period.     

Assessment of benefits and risks of landfill materials for agriculture in Eritrea

In Eritrea, farmers have applied landfill materials as fertiliser to their fields for several decades. A sampling scheme in the landfill site of Asmara and selected farmers' fields was carried out to investigate the benefits and risks of using landfill materials for agriculture. Soil samples were collected from farmers' fields (7 samples) and from the Asmara landfill site (12 samples). The samples were analysed for major plant nutrients, heavy metals (Cd, Cr, Cu, Pb, Ni, Hg and Zn), and some physical properties. Nearly 65% (by weight) of the total landfill material mined from the landfill site constituted waste fractions of various substances. The remaining 35% was composed of soil-like materials, which are apparently used to fertilize agricultural soils. The average organic matter, total nitrogen, and available phosphorus contents of soils with landfill material measured 2.4%, 0.13%, and 45 mg kg(-1), respectively. However, soils without landfill material consisted of 1.1 % organic matter, 0.04% total N, and <40 mg kg(-1) of available P. Except for Hg, all the other heavy metals in the landfill site showed values above the permissible limits. In particular, the average concentrations of Cu (913 mg kg(-1)) and Pb (598 mg kg(-1)) in the landfill site were nine-fold and four-fold greater than the allowable limits, respectively. It is, therefore, suggested that composting fresh organic wastes should be considered and tested as an alternative material for fertilising agricultural soils and to maintain the quality of the environment.     

The mountain view controlled landfill project field experiment

The Mountain View controlled landfill project was undertaken in response to the need to optimize energy recovery from landfills, accelerate stabilization, and control gas migration and explosion hazards in the vicinity of landfills. The major objectives of the project were (1) to test the hypothesis that both yield and rate of landfill methanogenesis can be increased by controlling specific conditions within a landfill bioreactor, and (2) to quantify landfill gas production in a field-scale experiment with complete gas recovery so that a measure of landfill gas recovery efficiency can be established. Of particular importance for the design of the field experiment were the synergistic effects of moisture content, seed, and buffer additions on methanogenesis in landfilled municipal solid wastes. The experiment included six landfill cells considered as representative of actual landfills. The effect of moisture content, seed, and buffer was studied in terms of the water content of the refuse additions mixture on a total weight basis, the ratio of organic sludge dry solids to refuse dry solid (seed/nutrient), and the ratio of buffer solids to water present in the refuse/additions mixture.     

Analyzing nutrient distribution in different particle-size municipal aged refuse

To investigate the feasibility of using aged municipal solid waste as farmland soil, it is essential to study its nutritive compositions for plant growth. Previous studies have demonstrated that the properties of different particle-size aged refuse are very different, therefore, the present study was conducted to evaluate the adequacy of three elements (N, P, K) and the fractionation of inorganic P in the aged refuse with a particle-size distribution of 900 to 300, 300 to 150, 150 to 105, 105 to 90 and 90 to 0 μm. The results indicate that (1) total quantities of N, P, K were much larger than that in the general soil and the quantities of available N, P and K were also adequate; (2) total content of P was sufficient, but the ratio of available-P to total P was not high enough; (3) with the decrease of particle size, the contents of these elements presented different trends. The results implicate that total contents of N, P and K were enough for the aged refuse being exploited as cultivated soil, and different gradation of aged refuse could be added to improve poor soils. It provides scientific evidence for utilizing different particle-size aged refuse comprehensively.     

Relationships between analytical methods utilized as tools in the evaluation of landfill waste stability

In this study, the refuse from 12 landfills of various ages ranging from fresh refuse to material 11 years old was collected, and changes in the bio-stability parameters were determined. The parameters measured included cellulose, lignin, biochemical methane potential (BMP) and volatile solids, along with plastics. These parameters, along with the cellulose to lignin ratio were compared to determine which were most indicative of the bio-stability of the refuse. Lignin and volatile solids measurements were affected by plastics in refuse samples. Plastics increased both lignin and volatile solids measurements by approximately 10%. Cellulose and volatile solids measurements correlated well with age, each other, and with BMP measurements and were therefore considered the best parameters to determine stability. Data for the Riverbend landfill, a landfill with a moisture content of 48%, which is similar to that of bioreactor landfills, showed that degradation was nearly complete after 5 years as indicated by low values for cellulose and BMP.     

Characterization and removal of dissolved organic matter (DOM) from landfill leachate rejected by nanofiltration

Dissolved organic matter (DOM) from wastewater rejected by nanofiltration from a landfill leachate treatment plant was fractionated into humic acid (HA), fulvic acid (FA) and hydrophilic (HyI) fractions. It was found that humic substances (HA and FA) composed 75% of the total dissolved organic carbon (DOC) concentration of the DOM, with an average molecular weight of about 1000 Da. Elemental analysis, infrared spectroscopy, UV-visible spectroscopy and acid-base titration observations showed that the HA and FA of the DOM exhibited lower fractions of condensed aromatic functional groups but larger fractions of acidic groups compared with other aquatic DOMs. The properties of HA and FA were similar, but HA exhibited more complete humification, while the HyI fraction had more acidic groups. An aminated polymeric adsorbent NDA-8 was used to adsorb the DOM in the wastewater along with primary coagulation. Results of bench-scale experiments indicated that the treatment process could effectively remove the DOM and heavy metals while desorption liquid was 10 times more condensed than raw wastewater. Results of desorption and reproducibility tests consolidated the strong application potential of this treatment process as an advanced landfill leachate treatment technology.     

Influence of oxygen flow rate on reaction rate of organic matter in leachate from aerated waste layer containing mainly incineration ash

It is known that aeration reduces rapidly the concentration of organic matter in leachate. However, the oxygen flow rate required to attain a certain reaction rate of organic matter should be carefully estimated. In this study, using the oxygen ratio (the ratio of oxygen flow rate by aeration to oxygen consumption rate of waste layer) as a parameter, the reaction rate of organic matter in leachate from landfilled incineration ash and incombustible waste upon aeration was evaluated. Total organic carbon (TOC) in the leachate was reduced rapidly when the oxygen ratio was high. The decomposition rate exceeded the elution rate of TOC in the leachate from the waste layer for several days when the oxygen ratio was above 10². The results indicate that the oxygen ratio can be used as a parameter for the aeration operation in actual landfill sites, to rapidly stabilize organic matter in leachate.     

Comparison of semi-aerobic and anaerobic degradation of refuse with recirculation after leachate treatment by aged refuse bioreactor

Two fresh refuse bioreactors (F1 and F2) were operated under semi-aerobic and anaerobic conditions, respectively. The leachate from the bioreactors F1 and F2 was introduced into the aged refuse bioreactors (A1 and A2), and the effluent from A1 and A2 was subsequently recirculated into F1 and F2, respectively. The effect of the semi-aerobic recirculation process on refuse degradation was investigated, comparing it with that of the anaerobic recirculation process. Results indicate that the semi-aerobic recirculation process can increase the accumulated net production of leachate and promote evaporation. The accumulated net production of refuse in F1 is 320 mL/kg and that of F2 is 248 mL/kg, with leachate reduction amounting to 315 and 244 mL/kg refuse, respectively. The leachate quantity reduction of semi-aerobic and anaerobic leachate recirculation process accounted for 98.4% and 98.3% of the accumulated net production of leachate, respectively. The semi-aerobic leachate recirculation process can improve the biodegradation of organic matter from fresh refuse and the reduction rate of the pollutant concentration in leachate. This should shorten considerably the time required to meet the discharge standard and the time of stabilization of the refuse as observed in the anaerobic recirculation process. It was predicted that the COD concentration of leachate from the anaerobic recirculation process would reach 1000 mg/L in the anaerobic recirculation process after 2.2 years, as for semi-aerobic leachate recirculation process it is about 100 days. Compared with anaerobic recirculation process, the semi-aerobic recirculation process is more effective on NH₃-N transformation and TN removal. The NH₃-N and TN concentration of F1 is far below those of F2 at the end of our experiment. Refuse settlement in the semi-aerobic recirculation process was faster than that in the anaerobic recirculation process. At the end of the experiment, refuse settlement ratios in the semi-aerobic and anaerobic bioreactors were 33.5% and 18%, respectively.     

Nitrogen management in bioreactor landfills

One scenario for long-term nitrogen management in landfills is ex situ nitrification followed by denitrification in the landfill. The objective of this research was to measure the denitrification potential of actively decomposing and well decomposed refuse. A series of 10-l reactors that were actively producing methane were fed 400 mg NO3-N /l every 48 h for periods of 19-59 days. Up to 29 nitrate additions were either completely or largely depleted within 48 h of addition and the denitrification reactions did not adversely affect the leachate pH. Nitrate did inhibit methane production, but the reactors recovered their methane-producing activity with the termination of nitrate addition. In well decomposed refuse, the nitrate consumption rate was reduced but was easily stimulated by the addition of either acetate or an overlayer of fresh refuse. Addition of acetate at five times the amount required to reduce nitrate did not lead to the production of NH4+ by dissimilatory nitrate reduction. The most probable number of denitrifying bacteria decreased by about five orders of magnitude during refuse decomposition in a reactor that did not receive nitrate. However, rapid denitrification commenced immediately with nitrate addition. This study shows that the use of a landfill as a bioreactor for the conversion of nitrate to a harmless byproduct, nitrogen gas, is technically viable.     

Nitrogen removal from recycled landfill leachate by ex situ nitrification and in situ denitrification

A three-compartment system, comprising a landfill column with fresh municipal solid waste, a column with a well-decomposed refuse layer as methane producer, and a sequential batch reactor as ex situ nitrifying reactor, was employed to remove nitrogen from municipal solid waste leachate. Since food waste comprised a major portion of refuse collected in Shanghai, an intense hydrolysis reaction occurred and caused the rapid accumulation of ammonia nitrogen (NH(3)-N) and total organic carbon in the leachate. This paper discusses the role of the three mentioned units and the design and operation of the proposed system. With most NH(3)-N being converted to nitrite nitrogen (NO(2)(-)-N) or nitrate nitrogen (NO(3)(-)-N) by the nitrifying reactor, and with the well-decomposed refuse layer transforming most dissolved organic compounds to CO(2), carbonates and methane, it was found that the fresh refuse column could efficiently denitrify the hydrolyzed nitrogen to N(2) gas. The role of the three mentioned units and comments on the design and operation of the proposed system are also discussed.     

A complete mass balance of a complex combined anaerobic/aerobic municipal source-separated waste treatment plant

In this study a combined anaerobic/aerobic full-scale treatment plant designed for the treatment of the source-separated organic fraction of municipal solid waste (OFMSW) was monitored over a period of one year. During this period, full information was collected about the waste input material, the biogas production, the main rejects and the compost characteristics. The plant includes mechanical pre-treatment, dry thermophilic anaerobic digestion, tunnel composting system and a curing phase to produce compost. To perform the monitoring of the entire plant and the individual steps, traditional chemical methods were used but they present important limitations in determining the critical points and the efficiency of the stabilization of the organic matter. Respiration indices (dynamic and cumulative) allowed for the quantitative calculation of the efficiency of each treatment unit. The mass balance was calculated and expressed in terms of Mgy(-1) of wet (total) matter, carbon, nitrogen and phosphorus. Results show that during the pre-treatment step about 32% of the initial wet matter is rejected without any treatment. This also reduces the biodegradability of the organic matter that continues to the treatment process. About 50% of the initial nitrogen and 86.4% of the initial phosphorus are found in the final compost. The final compost also achieves a high level of stabilization with a dynamic respiration index of 0.3±0.1g O(2) per kg of total solids per hour, which implies a reduction of 93% from that of the raw OFMSW, without considering the losses of biodegradable organic matter in the refuse (32% of the total input). The anaerobic digestion process is the main contributor to this stabilization.     

Size fractionation of organic matter and heavy metals in raw and treated leachate

This study characterized the organic matter and heavy metals in the leachate from two typical municipal solid waste (MSW) sanitary landfills in China, the recently established (3-year-old) Liulitun landfill and the mature (11-year-old) Beishenshu landfill, using a size fractionation procedure. The organic matter of all raw and treated leachate samples primarily existed in a truly-dissolved fraction with an apparent molecular weight (AMW) of <1 kDa, and its percentage decreased with an increase in overall AMW. The leachate from the newer landfill had a higher percentage of truly-dissolved organic matter. After anaerobic treatment, this leachate had a similar size fraction of organic matter to that seen for the raw leachate of the mature landfill. Biochemical processes had different removal efficiencies for various types of AMW organic matter, and the concentration of moderate AMW organic matter appeared to increase throughout these processes. Most of the heavy metals existed in a colloidal fraction (AMW >1 kDa and particle size <0.45 μm). The behaviors of different species of heavy metals had large variations. The size fractions of heavy metal species were significantly affected by treatment processes and landfill age, except for Zn. The concentration ratio of heavy metals to organic matter was maximal in the colloidal fraction and showed an inverse change to that seen for organic matter concentration changes caused by biochemical processes. Consequently, the pollution levels of heavy metals were substantially increased by treatment processes, although their concentrations decreased.     

Use of thermal analysis techniques (TG-DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application

The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and provides a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO₂ respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic matter, showed a strong correlation with cumulative respiration. Results obtained support the hypothesis of a potential link between the thermal and biological stability of the studied organic materials, and consequently the ability of thermal analysis to characterize the maturity of municipal organic wastes and composts.     

Risk assessment of an old landfill regarding the potential of gaseous emissions – A case study based on bioindication,FT-IR spectroscopy and thermal analysis

Risk assessment of two sections (I and II) of an old landfill (ALH) in Styria (Austria) in terms of reactivity of waste organic matter and the related potential of gaseous emissions was performed using conventional parameters and innovative tools to verify their effectiveness in practice. The ecological survey of the established vegetation at the landfill surface (plant sociological relevés) indicated no relevant emissions over a longer period of time. Statistical evaluation of conventional parameters reveals that dissolved organic carbon (DOC), respiration activity (RA₄), loss of ignition (LOI) and total inorganic carbon (TIC) mostly influence the variability of the gas generation sum (GS₂₁). According to Fourier Transform Infrared (FT-IR) spectral data and the results of the classification model the reactivity potential of the investigated sections is very low which is in accordance with the results of plant sociological relevés and biological tests. The interpretation of specific regions in the FT-IR spectra was changed and adapted to material characteristics. Contrary to mechanically–biologically treated (MBT) materials, where strong aliphatic methylene bands indicate reactivity, they are rather assigned to the CH vibrations of plastics in old landfill materials. This assumption was confirmed by thermal analysis and the characteristic heat flow profile of plastics containing landfill samples. Therefore organic carbon contents are relatively high compared to other stable landfills as shown by a prediction model for TOC contents based on heat flow profiles and partial least squares regression (PLS-R). The stability of the landfill samples, expressed by the relation of CO₂ release and enthalpies, was compared to unreactive landfills, archeological samples, earthlike materials and hardly degradable organic matter. Due to the material composition and the aging process the landfill samples are located between hardly degradable, but easily combustible materials and thermally resistant materials with acquired stability.     

Toxicological evaluation of the chemical oxidation methods for landfill stabilization

As the stabilization criteria for landfill sites, only chemical criteria for the leachate discharges from the landfill sites have been used in Japan and many other countries. Recently, chemical oxidation has been developed as a method for the early-stabilization of landfills. However, by-products that are difficult to detect by chemical analysis can be produced by this method. Therefore, toxicity tests are useful tools for detecting the changes of leachate quality after application of this method. The heat source in the A landfill was analyzed by organic position inquiry technology, and ozone-treated leachate was sprayed back to the heat source in the landfill. Toxicity changes of the leachate after the spray were monitored using Microtoxtrade mark, ToxScreen-II, and DaphTox tests. The hardly-degradable organic matter was efficiently removed and toxicities of the leachate in the heat source decreased after the application. These toxicity results were significantly related to chemical oxygen demand (COD) changes. Thus, it was concluded that the toxicity tests were effective for monitoring the leachate quality after applying the chemical oxidation method for landfill stabilization, and its incorporation to establish the criteria for early-stabilization of landfill sites needs to be considered.     

Biodegradable organic matter in municipal solid waste incineration bottom ash

For investigation of the behavior of municipal solid waste incineration bottom ash in landfill, we have analysed bottom ash samples taken after the quench tank as well as after five months of storage in the laboratory for elements and organic constituents. Water extractable organic carbon, particulate organic carbon, amino acids, hexosamines and carbohydrates considerably decreased during the five months of storage and their spectra revealed microbial reworking. This shows that the organic matter present in the bottom ash after incineration can provide a substrate for microbial activity. The resulting changes of the physico-chemical environment may effect the short-term behavior of the bottom ash in landfill.     

The applicability of Fourier transform infrared (FT-IR) spectroscopy in waste management

State and stability or reactivity of waste materials are important properties that must be determined to obtain information about the future behavior and the emission potential of the materials. Different chemical and biological parameters are used to describe the stage of organic matter in waste materials. Fourier transform infrared spectroscopy provides information about the chemistry of waste materials in a general way. Several indicator bands that are referred to functional groups represent components or metabolic products. Their presence and intensity or their absence shed light on the phase of degradation or stabilization. The rapid assessment of the stage of organic matter decomposition is a very important field of application. Therefore, infrared spectroscopy is an appropriate tool for process and quality control, for the assessment of abandoned landfills and for checking of the successful landfill remediation. A wide range of applications are presented in this study for different waste materials. Progressing stages of a typical yard/kitchen waste composting process are shown. The fate of anaerobically "stabilized" leftovers in a subsequent liquid aerobic process is revealed by spectroscopic characteristics. A compost that underwent the biological stabilization process is distinguished from a "substrate" that comprises immature biogenic waste mixed with mineral compounds. Infrared spectra of freeze-dried leachate from untreated and aerated landfill material prove the effect of the aerobic treatment during 10 weeks in laboratory-scale experiments.     

Stable isotope signatures for characterising the biological stability of landfilled municipal solid waste

Stable isotopic signatures of landfill leachates are influenced by processes within municipal solid waste (MSW) landfills mainly depending on the aerobic/anaerobic phase of the landfill. We investigated the isotopic signatures of δ¹³C, δ²H and δ¹⁸O of different leachates from lab-scale experiments, lysimeter experiments and a landfill under in situ aeration. In the laboratory, columns filled with MSW of different age and reactivity were percolated under aerobic and anaerobic conditions. In landfill simulation reactors, waste of a 25 year old landfill was kept under aerobic and anaerobic conditions. The lysimeter facility was filled with mechanically shredded fresh waste. After starting of the methane production the waste in the lysimeter containments was aerated in situ. Leachate and gas composition were monitored continuously. In addition the seepage water of an old landfill was collected and analysed periodically before and during an in situ aeration.We found significant differences in the δ¹³C-value of the dissolved inorganic carbon (δ¹³C-DIC) of the leachate between aerobic and anaerobic waste material. During aerobic degradation, the signature of δ¹³C-DIC was mainly dependent on the isotopic composition of the organic matter in the waste, resulting in a δ¹³C-DIC of ?20‰ to ?25‰. The production of methane under anaerobic conditions caused an increase in δ¹³C-DIC up to values of +10‰ and higher depending on the actual reactivity of the MSW. During aeration of a landfill the aerobic degradation of the remaining organic matter caused a decrease to a δ¹³C-DIC of about ?20‰. Therefore carbon isotope analysis in leachates and groundwater can be used for tracing the oxidation–reduction status of MSW landfills.Our results indicate that monitoring of stable isotopic signatures of landfill leachates over a longer time period (e.g. during in situ aeration) is a powerful and cost-effective tool for characterising the biodegradability and stability of the organic matter in landfilled municipal solid waste and can be used for monitoring the progress of in situ aeration.     

Temporal variation of leachate quality from pre-sorted and baled municipal solid waste with high organic and moisture content

Landfill leachate characterization is a critical factor in establishing a corresponding effective management strategy or treatment process. However, it is often difficult to forecast leachate quality because of a variety of influencing factors such as waste composition and landfill operations. This paper describes leachate formation mechanisms, summarizes leachate quality indicators, and investigates the temporal variation of leachate quality from pre-sorted and baled municipal solid waste characterized with high organic and moisture content. The purpose of the study is to evaluate the potential effects of waste composition and site-specific operational procedures on biodegradation processes and leachate quality at a field-scale landfill that receives in excess of 1800 tonnes per day of refuse. For this purpose, waste disposal and leachate generation rates were monitored and leachate samples were collected for a period of 18 months during the early stages of refuse deposition. Chemical analysis was performed on the samples and the temporal variation of several parameters were monitored including pH, COD, TOC, TDS, chlorides, sulfates, orthophosphates, nitrates, ammonia nitrogen, hardness, and heavy metals. Chemical concentration levels were related to biological activity within the landfill and the results indicated that: (1) pre-sorting and baling of the waste did not hinder waste stabilization; and (2) the high organic and moisture contents resulted in an extremely strong leachate, particularly at the onset of biodegradation processes, which can affect the leachate treatment facility.