Municipal Landfill Leachate Research Articles

Anaerobic co-digestion of wine/fruit-juice production waste with landfill leachate diluted municipal sludge cake under semi-continuous flow operation

Anaerobic co-digestion of four organic waste streams; a thickened waste activated sludge (TWAS) and screen cake (SC) from a fruit-juice/winery wastewater treatment plant along with municipal sludge cake (MC) and landfill leachate (LL) was evaluated. A total of eight semi-continuously-fed single and co-digesters were operated side-by-side at sludge retention times (SRT) of 20 and 10days. Co-digestion of industrial waste streams (TWAS and SC) with MC and LL resulted in increased operational stability compared to the single digestion of industrial TWAS at the higher organic loading (10 d SRT). Although digester operational temperature had no statistically significant effect on organics removal and biogas production, mesophilic digesters had consistently higher total coliform densities (8838–37,959 most probable number or MPN/g-dry weight) compared to the thermophilic digesters (41–6723MPN/g-dry weight) at both SRTs. Coliform analysis results also proved that most of the thermophilic digestates could be classified as Class A biosolids according to regulations. Furthermore, addition of industrial TWAS to co-digesters enhanced the dewaterability of the digested streams. A cost-benefit analysis confirmed the benefits and indicated that a full-scale co-digester utilizing all four waste streams can decrease the total capital and operational cost by 22% ($10.52million).

Anoxic/aerobic granular active carbon assisted MBR integrated with nanofiltration and reverse osmosis for advanced treatment of municipal landfill leachate

Anoxic/aerobic granular active carbon assisted membrane bioreactors (A/O-GAC-MBR) integrated with nanofiltration (NF)–reverse osmosis (RO) were used for leachate treatment of the Taizhou Municipal Landfill plant. In order to investigate the effect of GAC on the performance of MBR, a hybrid MBR with GAC dosed and a conventional MBR were operated in parallel. Two pilot scale MBRs showed excellent and stable removal efficiency with average above 80% for chemical oxygen demand (COD) and ammonia-nitrogen (NH3-N). It was noticed that the amount of high-valence metal ions were removed more than low-valence ones. By comparison, the addition of GAC not only improved the removal of hazardous organic pollutants and heavy metals, but also enhanced bioflocculation and particle size of flocs, which greatly alleviated membrane fouling. NF and RO membranes were then used for advanced treatment of MBR effluents. NF membrane exhibited excellent color removal rate of 93.75% compared to 41.82% of A/O-MBR. With the advantage of NF pretreatment, RO membrane held a steadier and higher flux as well as salt rejection than other cases reported. The final permeate from RO was proved to exceed related qualification for reutilization and can easily be recycled in industry.

Reuse of ferric sludge as an iron source for the Fenton-based process in wastewater treatment

Abstract A mature municipal landfill leachate (S1), a wood soaking basin effluent from a plywood manufacturing plant (S2), and a leachate collected from a semicoke landfill area of an oil-shale thermal treatment plant (S3) were subjected to the Fenton/Fenton-based treatment (H 2 O 2 /Fe 2+ , H 2 O 2 /Fe 3+ and H 2 O 2 /sludge systems). The results of ferric coagulation trials indicated a high efficacy in S2; thus, only pre-coagulated samples (cS2) were further treated by the H 2 O 2 /iron systems. Irrespective of reaction duration, S1 was more recalcitrant to oxidation than cS2 and S3. The optimal COD/H 2 O 2 weight ratio for cS2 and S3 was 1:1 with respective 21(35) and 36(45)% residual COD(DOC). In the case of S1, the COD/H 2 O 2 w/w of 1:3.45 proved the most efficient with 30 and 35% residual COD and DOC, respectively. The results also indicated an increase in BOD 7 /COD ratio and a reduction in the acute toxicity to Daphnia magna of the studied wastewater samples after the Fenton/Fenton-based treatment. The application of the Fenton-based process catalysed with iron-containing sludge exhibited efficacies similar to classical Fenton treatment over four reuse cycles. The reuse of ferric sludge without any regeneration as an iron source in the Fenton-based process was displayed as a feasible solution to minimise the production of hazardous ferric waste and reduce the overall cost of the treatment process.

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.

The competency of various applied strategies in treating tropical municipal landfill leachate

Leachate is a major pollution source associated with municipal solid waste landfill. This study was carried out to evaluate the effectiveness of various techniques in treating mature landfill leachate generated from landfill in Malaysia, a tropical country. Treatment processes such as biological, ion exchange, coagulation–flocculation, adsorption, advanced oxidation processes (AOPs), and flotation were analyzed. The efficiency of each process was analyzed based on chemical oxygen demand (COD), color, and NH3-N percentage removals. Ion exchange treatment via cationic/anionic sequence achieved the best removal of color (96.8%), COD (87.9%), and NH3-N (93.8%) from leachate as compared with other treatment methods. Coagulation–flocculation and AOPs were successful for COD and color removals from leachate. However, both could not treat NH3-N effectively. Biological treatment could remove NH3-N (71%) effectively, but it was poor in terms of COD (29%) and color (22%) removals. Adsorption via a new carbon–mineral composite exhibited better removal of both COD (68.4%) and NH3-N (92.6%) from stabilized leachate.

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.

Comparison of the retention of selected PAHs from municipal landfill leachate by RO and UF processes

The aim of the conducted research was to compare the changes in the retention of polycyclic aromatic hydrocarbons (PAHs) during membrane filtration (ultrafiltration—UF and reverse osmosis—RO). In the study, municipal landfill leachate was used. In the first stage of testing, leachates were filtrated on the sand bed (prefiltration). After prefiltration, they were directed to the membrane module for main filtration. The ultrafiltration process was carried out at the transmembrane pressure of 0.1–0.2 MPa. The membrane separation process was based on a capillary membrane type ZW-10. The transmembrane pressure of the reverse osmosis stood at 2 MPa and for this process one nylon membrane (ADF) was used. The prepared samples of the municipal landfill leachates were subjected to extraction with applying 2-propanol. Extracts were cleared on octadecyl C18 columns, and then concentrated in the nitrogen stream. High-performance liquid chromatography HPLC with fluorescence detection (model HPLC THERMO) was used for qualitative and quantitative analysis of PAHs. During the process, a decrease in the concentrations of most tested hydrocarbons was observed. The initial concentrations of PAHs in the municipal landfill leachates were in the range 17.5–30.4 mg / L. The efficiency of the removal of hydrocarbons grouped according to a number of rings was in the range of 48 (for naphthalene) to 73% (for 6-ring of PAHs) in ultrafiltration technique. However, the greater efficiency retention of PAHs was obtained for RO. The average value of the retention coefficient for RO was equal to 71% (for individual hydrocarbons were in the range of 19–100%).

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.

Fungal and enzymatic treatment of mature municipal landfill leachate

The aim of our study was to evaluate biotreatability of mature municipal landfill leachate by using white rot fungus and its extracellular enzymes. Leachates were collected in one active and one closed regional municipal landfill. Both chosen landfills were operating for many years and the leachates generated there were polluted by organic and inorganic compounds. The white rot fungus Dichomitus squalens was able to grow in the mature leachate from the closed landfill and as it utilizes present organic matter as a source of carbon, the results were showing 60% of DOC and COD removal and decreased toxicity to the bacterium Aliivibrio fischeri. On the other hand, growth of the fungus was inhibited in the presence of the leachate from the active landfill. However, when the leachate was introduced to a crude enzyme filtrate containing extracellular ligninolytic enzymes, removal levels of COD and DOC reached 61% and 44%, respectively. Furthermore, the treatment led to detoxification of the leachate to the bacterium Aliivibrio fischeri and to reduction of toxicity (42%) to the plant Sinapis alba. Fungal and enzymatic treatment seems to be a promising biological approach for treatment of mature landfill leachates and their application should be further investigated.

Treatment of municipal landfill leachate using magnetic porous ceramsite carrier

In this study, porous ceramsite carrier was modified using magnetic material as raw material. The magnetic porous ceramsite carrier was applied to the treatment of municipal landfill leachate. The results showed that the removal efficiency of chemical oxygen demand (COD), NH3-N and Cr6+ in the supernatant were all more than 90% after 30 days with the aeration rate of 3 L/h, the aeration time of 16 h/d and the temperature of 20–30 °C. The output concentration met the national life Landfill Pollution Control Standard (PR China GB16889-2008) requirements. The magnetic properties significantly improved the carrier biofilm formation, compared with the conventional activated sludge process and non-magnetic carrier. The COD, NH3-N and Cr6+ removal efficiency were 5–10%, 5–7% and 5–10%, respectively.

Attenuation of municipal landfill leachate through land treatment

The treatment of municipal landfill’s leachate is considered as one of the most significant environmental issues. In this study a laboratory experiment was conducted through land treatment, achieving an efficient and economical method by using Vetiver plant. Moreover, the effects of land treatment of leachate of municipal landfills on the natural reduction of organic and inorganic contaminants in the leachate after the pre-treatment in the Aradkouh disposal center are invested. Three pilots including the under-investigation region’s soil planted by Vetiver plant, the region’s intact soil pilot and the artificial composition of the region’s soil including the natural region’s soil, sand, and rock stone are used. The leachate, having passed its initial treatment, passed through the soil and to the pilot. It was collected in the end of the pilots and its organic and inorganic contaminants were measured. However, the land treatment of leachate was conducted in a slow rate at various speeds. According to the results, in order to remove COD, BOD5, TDS, TSS, TOC the best result was obtained in the region’s soil planted with Vetiver plant and at the speed of 0.2 ml per minute which resulted 99.1%, 99.7%, 52.4%, 98.8%, 94.9% removal efficiencies, respectively. It also can be concluded that the higher the organic rate load is, the lower the efficiency of the removal would be. In addition, EC & pH were measured and the best result was obtained in the region’s soil planted with Vetiver plant and at the speed of 0.2 ml/min.

Pilot-scale nitrogen removal from leachate by ex situ nitrification and in situ denitrification in a landfill bioreactor

A combined process consisting of ex situ nitrification and in situ denitrification in landfill refuse was studied in pilot scale for nitrogen removal from municipal landfill leachate. The results showed that above 80% of partial nitrification ratio and an average COD loading rate of 1.50kgm−3d−1 were steadily maintained under DO concentrations of 1.0–1.7mgL−1 in the aerobic reactor. Quantitative PCR results indicated that nitrite-oxidizing bacteria being sensitive to DO fluctuations lead to partial nitrification when free ammonia inhibition was weak. Nitrified landfill leachate could be denitrified in the landfill bioreactor with maximum total oxidizing nitrogen removal rate of 67.2gNt−1TSwasted−1. Clone and sequencing analysis of denitrifying bacterial nirS gene inferred that heterotrophic denitrifier Azoarcus tolulyticu was the primary nitrogen converter in the landfill bioreactor. The obtained results will provide valuable information for optimizing the design and operation of a landfill bioreactor.

Determination of Perfluoroalkyl Substances in Municipal Landfill Leachates from Beijing, China

Determination of Perfluoroalkyl Substances in Municipal Landfill Leachates from Beijing, China

Sperm functional parameters and erythrocytes oxidant–antioxidant imbalance during municipal landfill leachate treatment withdrawal in rats

Adequate information on how leachates affect hematological and reproductive functions is necessary to help in linking causality with predictable response. The present study investigated the effects of Olushosun municipal landfill leachate (OMLL) exposure and withdrawal on sperm characteristics and erythrocytes oxidant–antioxidant balance in rats. Adult male Wistar rats were exposed to 0%, 12.5% and 25% OMLL in drinking water for 28 days. One-half of the rats in each group were sacrificed on day 29 while the remaining one-half stayed an additional 28 days without treatment. OMLL exposure significantly decreased sperm functional parameters, disrupted antioxidant systems with concomitant elevation in hydrogen peroxide and malondialdehyde levels in erythrocytes and sperm. Following withdrawal of treatment, OMLL-mediated decrease in sperm count and daily sperm production were reversed to near control. However, erythrocytes and sperm oxidative damage, increased sperm abnormalities, decreased epididymis weight, sperm progressive motility and testicular sperm number persisted and were consistent with results obtained from rats sacrificed immediately after OMLL treatment. Collectively, OMLL-induced irreversible oxidative damage to erythrocytes and sperm in rats within the time course of investigation. These findings highlight potential adverse effects of OMLL on individuals unduly exposed to leachates contaminated substances.

QUALITATIVE RESEARCH AND EVALUATION OF LANDFILL LEACHATE / KOKYBINIAI SĄVARTYNO FILTRATO TYRIMAI IR VERTINIMAS

Currently, depositing municipal waste in landfills is the dominating method in Lithuania. A large amount of landfill leachate is the main environmental problem. Municipal waste landfill leachate is characterized by high biochemical oxygen demand (BOD) containing a number of heavy metals and concentration of organic compounds. The colmatation of landfill leachate collection systems is another burning problem that occurs due to certain characteristics of leachate such as suspended solids, an increase in calcium and magnesium concentrations and vital activity of microorganisms. Therefore, it is necessary to examine conditions affecting these parameters. The paper presents and analyses the characteristics of experimental data, assesses the factors having the greatest influence on recent development and introduces the measures that should be taken into account so that to the ensure optimal operation of the systems for collecting municipal waste landfill leachate. Article in Lithuanian. Santrauka Pagrindinis atliekų tvarkymo būdas Lietuvoje yra jų deponavimas sąvartynuose. Viena iš svarbiausių aplinkosauginių problemų – dideli susidarantys sąvartyno filtrato kiekiai. Komunalinių atliekų sąvartynų filtratui būdinga didelis biocheminio deguonies suvartojimas (BDS), filtrate taip pat nemažà sunkiųjų metalų bei organinių junginių koncentracija. Svarbu išskirti ir tokią problemą kaip sąvartyno filtrato surinkimo sistemų kolmatacija, pasireiškianti dėl tam tikrų filtrato savybių: skendinčiųjų medžiagų, kalcio ir magnio koncentracijų padidėjimo ir mikroorganizmų gyvybinės veiklos. Būtina įvertinti sąlygas, turinčias įtakos šių parametrų kitimui. Pateikti minėtų savybių eksperimentinių tyrimų duomenys ir analizė. Įvertinta, kokie veiksniai turi didžiausią įtaką filtrato parametrų kitimui, pavyzdžiui, tai, jog bendrasis kietumas (kalcis ir magnis) lemia pH didėjimą, t. y. terpės šarmėjimą. Be to, išanalizuota, kokių priemonių reikėtų imtis optimaliam komunalinių atliekų sąvartyno filtrato surinkimo sistemų veikimui užtikrinti.

Treatment of landfill leachate by Fenton process: parametric and kinetic studies

Fenton treatment of leachate of municipal landfill was investigated in this study. Physical and chemical characteristics of the leachate indicated that the waste is alkaline and is characterized by extremely high concentration of organic compounds. Different reaction conditions of Fenton treatment were examined including H2O2/chemical oxygen demand (COD) and Fe2+/H2O2 ratios in the present work. COD of leachate after Fenton treatment was removed by about 77 and 83% for initial COD 6,250 and 13,300 mgO2/L, respectively. Such a maximum removal was achieved at pH 3 and using reagent dosages as high as H2O2/COD = 4.4 and H2O2/Fe2+value of 50. Complete oxidation was not achieved even at optimum conditions due to the presence of inhibitors (carbonate) in the leachate wastewater. After removal of high carbonate content, the same removal efficiency could be achieved with lower H2O2/COD ratio (i.e. H2O2/COD = 3.3). A simplified kinetic study for Fenton treatment of leachate wastewater has been performed.

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.

Decontamination of a municipal landfill leachate from endocrine disruptors using a combined sorption/bioremoval approach

Sorption and biodegradation are the main mechanisms for the removal of endocrine disruptor compounds (EDs) from both solid and liquid matrices. There are recent evidences about the capacity of white-rot fungi to decontaminate water systems from phenolic EDs by means of their ligninolytic enzymes. Most of the available studies report the removal of EDs by biodegradation or adsorption separately. This study assessed the simultaneous removal of five EDs—the xenoestrogens bisphenol A (BPA), ethynilestradiol (EE2), and 4-n-nonylphenol (NP), and the herbicide linuron and the insecticide dimethoate—from a municipal landfill leachate (MLL) using a combined sorption/bioremoval approach. The adsorption matrices used were potato dextrose agar alone or added with each of the following adsorbent materials: ground almond shells, a coffee compost, a coconut fiber, and a river sediment. These matrices were either not inoculated or inoculated with the fungus Pleurotus ostreatus and superimposed on the MLL. The residual amount of each ED in the MLL was quantified after 4, 7, 12, and 20 days by HPLC analysis and UV detection. Preliminary experiments showed that (1) all EDs did not degrade significantly in the untreatedMLL for at least 28 days, (2) the mycelial growth of P. ostreatus was largely stimulated by components of the MLL, and (3) the enrichment of potato dextrose agar with any adsorbent material favored the fungal growth for 8 days after inoculation. A prompt relevant disappearance of EDs in the MLL occurred both without and, especially, with fungal activity, with the only exception of the very water soluble dimethoate that was poorly adsorbed and possibly degraded only during the first few days of experiments. An almost complete removal of phenolic EDs, especially EE2 and NP, occurred after 20 days or much earlier and was generally enhanced by the adsorbent materials used. Data obtained indicated that both adsorption and biodegradation mechanisms contribute significantly to MLL decontamination from the EDs studied and that the efficacy of the methodology adopted is directly related to the hydrophobicity of the contaminant.

The Performance of Microelectrolysis in Improving the Biodegradability Landfill Leachate

The aim of this study was to check the effectiveness of microelectrolysis for the pretreatment of a municipal landfill leachate with the objective improving its overall biodegradability, evaluated in terms of BOD5/COD ratio, up to a value compatible with biological treatment. The best microelectrolysis operational conditions for achieving the desired COD values were: pH=2.0; granular activated carbon (GAC) =10 g/L; mass ratio of zero iron (Fe0)/GAC=2:1; reaction time=90 min. The BOD5/COD was significantly improved from 0.12 to 0.31, which allowed an almost 85% removal of COD by a sequential activated sludge process. The results show that the microelectrolysis is a promising technology to improve the biodegradability of mature landfill leachate.

Współoczyszczanie odcieków ze ściekami mleczarskimi w sekwencyjnym bioreaktorze membranowym

Współoczyszczanie odcieków ze ściekami mleczarskimi w sekwencyjnym bioreaktorze membranowym