Abstract: The work sought to understand the pattern of movement of contaminant from a continuous point source through soil. The soil used was sandy-loam in texture. The contaminant used was municipal solid waste landfill leachate, introduced as a point source through an entry point located at the center of top layer of the soil tank. Analyses were conducted after maturity periods of 50 and 80 days. The maximum change in chemical concentration was observed on soil samples at a radial distance of 0.25 m. Finite element approximation based model was used to assess the future prediction, management and remediation in the polluted area. The actual field data collected for the case study were used to calibrate the modeling and thus simulated the flow pattern of the pollutants through soil. MATLAB R2015a was used to visualize the flow of pollutant through the soil. Dispersion coefficient at 0.25 and 0.50 m radial distance from the point of application of leachate shows a measure of the spreading of a flowing leachate due to the nature of the soil medium, with its interconnected channels distributed at random in all directions. Surface plots of metals on soil after maturity period of 80 days shows a functional relationship between a designated dependent variable (Y), and two independent variables (X and Z). Comparison of measured and predicted profile transport along the depth after 50 and 80 days of leachate application and end of the experiment shows that there were no much difference between the predicted and measured concentrations as they were all lying close to each other. For the analysis of contaminant transport, finite difference approximation based model was very effective in assessing the future prediction, management and remediation in the polluted area. The experiment gave insight into the most likely pattern of movement of contaminant as a result of continuous percolations of the leachate on soil. This is important for contaminant movement prediction and subsequent remediation of such soils.
Abstract: Landfill leachate emerges as a promising feedstock for microbial fuel cells (MFCs). In the present investigation, direct air-breathing cathode-based MFCs are fabricated to investigate the potential of landfill leachate. Three MFCs that have different cathode areas are fabricated and investigated for 17 days under open circuit conditions. The maximum open circuit voltage (OCV) is observed to be as high as 1.29 V. The maximum cathode area specific power density achieved in the reactor is 1513 mW m-2. Further studies are under progress to understand the origin of high OCV obtained from landfill leachate-based MFCs.
Abstract: This study investigated the integrated removal of heavy metals, organic matter and nitrogen from landfill leachate using a novel laboratory scale constructed wetland system. The main objectives of this study were: (i) to assess the overall effectiveness of the constructed wetland system for treating landfill leachate; (ii) to examine the interactions and impact of key leachate constituents (heavy metals, organic matter and nitrogen) on the overall removal dynamics and efficiency. The constructed wetland system consisted of four stages operated in tidal flow and anoxic conditions. Results obtained from 215 days of operation have demonstrated extraordinary heavy metals removal up to 100%. Analysis of the physico- chemical data reveal that the controlling factors for metals removal were the anoxic condition and the use of the novel media (dewatered ferric sludge which is a by-product of drinking water treatment process) as the main substrate in the constructed wetland system. Results show that the use of the ferric sludge enhanced heavy metals removal and brought more flexibility to simultaneous nitrification and denitrification which occurs within the microbial flocs. Furthermore, COD and NH4-N were effectively removed in the system and this coincided with enhanced aeration in the 2nd and 3rd stages of the constructed wetland system. Overall, the results demonstrated that the ferric dewatered sludge constructed wetland system would be an effective solution for integrated removal of pollutants from landfill leachates.
Abstract: Landfill leachates contain a number of persistent pollutants, including heavy metals. They have the ability to spread in ecosystems and accumulate in fish which most of them are classified as top-consumers of trophic chains. Fish are freely swimming organisms; but perhaps, due to their species-specific ecological and behavioral properties, they often prefer the most suitable biotopes and therefore, did not avoid harmful substances or environments. That is why it is necessary to evaluate the persistent pollutant dispersion in hydroecosystem using fish tissue metal concentration. In hydroecosystems of hybrid type (e.g. river-pond-river) the distance from the pollution source could be a perfect indicator of such a kind of metal distribution. The studies were carried out in the Kairiai landfill neighboring hybrid-type ecosystem which is located 5 km east of the Šiauliai City. Fish tissue (gills, liver, and muscle) metal concentration measurements were performed on two types of ecologically-different fishes according to their feeding characteristics: benthophagous (Gibel carp, roach) and predatory (Northern pike, perch). A number of mathematical models (linear, non-linear, using log and other transformations) have been applied in order to identify the most satisfactorily description of the interdependence between fish tissue metal concentration and the distance from the pollution source. However, the only one log-multiple regression model revealed the pattern that the distance from the pollution source is closely and positively correlated with metal concentration in all predatory fish tissues studied (gills, liver, and muscle).
Abstract: Landfill waste is a common problem as it has an
economic and environmental impact even if it is closed. Landfill
waste contains a high density of various persistent compounds such
as heavy metals, organic and inorganic materials. As persistent
compounds are slowly-degradable or even non-degradable in the
environment, they often produce sublethal or even lethal effects on
aquatic organisms. The aims of the present study were to estimate
sublethal effects of the Kairiai landfill (WGS: 55°55‘46.74“,
23°23‘28.4“) leachate on the locomotor activity of rainbow trout
Oncorhynchus mykiss juveniles using the original system package
developed in our laboratory for automated monitoring, recording and
analysis of aquatic organisms’ activity, and to determine patterns of
fish behavioral response to sublethal effects of leachate. Four
different concentrations of leachate were chosen: 0.125; 0.25; 0.5 and
1.0 mL/L (0.0025; 0.005; 0.01 and 0.002 as part of 96-hour LC50,
respectively). Locomotor activity was measured after 5, 10 and 30
minutes of exposure during 1-minute test-periods of each fish (7 fish
per treatment). The threshold-effect-concentration amounted to 0.18
mL/L (0.0036 parts of 96-hour LC50). This concentration was found
to be even 2.8-fold lower than the concentration generally assumed to
be “safe” for fish. At higher concentrations, the landfill leachate
solution elicited behavioral response of test fish to sublethal levels of
pollutants. The ability of the rainbow trout to detect and avoid
contaminants occurred after 5 minutes of exposure. The intensity of
locomotor activity reached a peak within 10 minutes, evidently
decreasing after 30 minutes. This could be explained by the
physiological and biochemical adaptation of fish to altered
environmental conditions. It has been established that the locomotor
activity of juvenile trout depends on leachate concentration and
exposure duration. Modeling of these parameters showed that the
activity of juveniles increased at higher leachate concentrations, but
slightly decreased with the increasing exposure duration. Experiment
results confirm that the behavior of rainbow trout juveniles is a
sensitive and rapid biomarker that can be used in combination with
the system for fish behavior monitoring, registration and analysis to
determine sublethal concentrations of pollutants in ambient water.
Further research should be focused on software improvement aimed
to include more parameters of aquatic organisms’ behavior and to
investigate the most rapid and appropriate behavioral responses in
different species. In practice, this study could be the basis for the
development and creation of biological early-warning systems
(BEWS).
Abstract: Constructed Wetland (CW) is a reasonable method to
treat wastewater. Current study was carried out to co-treat landfill
leachate and domestic wastewater using a CW system. Typha
domingensis was transplanted to CW, which encloses two substrate
layers of adsorbents named ZELIAC and zeolite. Response surface
methodology and central composite design were employed to
evaluate experimental data. Contact time (h) and leachate-towastewater
mixing ratio (%; v/v) were selected as independent
factors. Phenols and manganese removal were selected as dependent
responses. At optimum contact time (48.7 h) and leachate-towastewater
mixing ratio (20.0%), removal efficiencies of phenols and
manganese removal efficiencies were 90.5%, and 89.4%,
respectively.
Abstract: The goal of this experiment is to evaluate the
effectiveness of different leachate pre-treatment options in terms of
COD and ammonia removal. This research focused on the evaluation
of physical-chemical methods for pre-treatment of leachate that
would be effective and rapid in order to satisfy the requirements of
the sewer discharge by-laws. The four pre-treatment options
evaluated were: air stripping, chemical coagulation, electrocoagulation
and advanced oxidation with sodium ferrate. Chemical
coagulation reported the best COD removal rate at 43%, compared to
18% for both air stripping and electro-coagulation, and 20% for
oxidation with sodium ferrate. On the other hand, air stripping was
far superior to the other treatment options in terms of ammonia
removal with 86%. Oxidation with sodium ferrate reached only 16%,
while chemical coagulation and electro-coagulation removed less
than 10%. When combined, air stripping and chemical coagulation
removed up to 50% COD and 85% ammonia.
Abstract: Due to the resultant leachate from waste
decomposition in landfills has polluter potential hundred times
greater than domestic sewage, this is considered a problem related to
the depreciation of environment requiring pre-disposal treatment.In
seeking to improve this situation, this project proposes the treatment
of landfill leachate using natural fibers intercropped with advanced
oxidation processes. The selected natural fibers were palm, coconut
and banana fiber.These materials give sustainability to the project
because, besides having adsorbent capacity, are often part of waste
discarded. The study was conducted in laboratory scale.In trials, the
effluents were characterized as Chemical Oxygen Demand (COD),
Turbidity and Color. The results indicate that is technically
promising since that there were extremely oxidative conditions, the
use of certain natural fibers in the reduction of pollutants in leachate
have been obtained results of COD removals between 67.9% and
90.9%, Turbidity between 88.0% and 99.7% and Color between
67.4% and 90.4%.The expectation generated is to continue evaluating
the association of efficiency of other natural fibers with other landfill
leachate treatment processes.
Abstract: The occurrence and removal of trace organic
contaminants in the aquatic environment has become a focus of
environmental concern. For the selective removal of carbamazepine
from loaded waters molecularly imprinted polymers (MIPs) were
synthesized with carbamazepine as template. Parameters varied were
the type of monomer, crosslinker, and porogen, the ratio of starting
materials, and the synthesis temperature. Best results were obtained
with a template to crosslinker ratio of 1:20, toluene as porogen, and
methacrylic acid (MAA) as monomer. MIPs were then capable to
recover carbamazepine by 93% from a 10-5 M landfill leachate
solution containing also caffeine and salicylic acid. By comparison,
carbamazepine recoveries of 75% were achieved using a nonimprinted
polymer (NIP) synthesized under the same conditions, but
without template. In landfill leachate containing solutions
carbamazepine was adsorbed by 93-96% compared with an uptake of
73% by activated carbon. The best solvent for desorption was
acetonitrile, with which the amount of solvent necessary and dilution
with water was tested. Selected MIPs were tested for their reusability
and showed good results for at least five cycles. Adsorption
isotherms were prepared with carbamazepine solutions in the
concentration range of 0.01 M to 5*10-6 M. The heterogeneity index
showed a more homogenous binding site distribution.
Abstract: The purpose of this study is to investigate the capacity
of natural Turkish zeolite for NH4-N removal from landfill leachate.
The effects of modification and initial concentration on the removal
of NH4-N from leachate were also investigated. The kinetics of
adsorption of NH4-N has been discussed using three kinetic models,
i.e., the pseudo-second order model, the Elovich equation, the
intraparticle diffuion model. Kinetic parameters and correlation
coefficients were determined. Equilibrium isotherms for the
adsorption of NH4-N were analyzed by Langmuir, Freundlich and
Tempkin isotherm models. Langmuir isotherm model was found to
best represent the data for NH4-N.
Abstract: Sampling and analysis of leachate from Bhalaswa
landfill and groundwater samples from nearby locations, clearly
indicated the likely contamination of groundwater due to landfill
leachate. The results of simulation studies carried out for the
migration of Chloride from landfill shows that the simulation results
are in consonance with the observed concentration of Chloride in the
vicinity of landfill facility. The solid waste disposal system presently
being practiced in Delhi consists of mere dumping of wastes
generated, at three locations Bhalaswa, Ghazipur, and Okhla without
any regard to proper care for the protection of surrounding
environment. Bhalaswa landfill site in Delhi, which is being operated
as a dump site, is expected to become cause of serious groundwater
pollution in its vicinity. The leachate from Bhalaswa landfill was
found to be having a high concentration of chlorides, as well as DOC,
COD. The present study was undertaken to determine the likely
concentrations of principle contaminants in the groundwater over a
period of time due to the discharge of such contaminants from
landfill leachates to the underlying groundwater. The observed
concentration of chlorides in the groundwater within 75m of the
radius of landfill facility was found to be in consonance with the
simulated concentration of chloride in groundwater considering one
dimensional transport model, with finite mass of contaminant source.
Governing equation of contaminant transport involving advection and
diffusion-dispersion was solved in matlab7.0 using finite difference
method.
Abstract: Mature landfill leachates contain some macromolecular organic substances that are resistant to biological degradation. Recently, Fenton-s oxidation has been investigated for chemical treatment or pre-treatment of mature landfill leachates. The aim of this study was to reduce the recalcitrant organic load still remaining after the complete treatment of a mature landfill leachate by Fenton-s oxidation post-treatment. The effect of various parameters such as H2O2 to Fe2+ molar ratio, dosage of Fe2+ reagent, initial pH, reaction time and initial chemical oxygen demand (COD) strength, that have an important role on the oxidation, was analysed. A molar ratio H2O2/Fe2+ = 3, a Fe2+ dosage of 4 mmol·L-1, pH 3, and a reaction time of 40 min were found to achieve better oxidation performances. At these favorable conditions, COD removal efficiency was 60.9% and 31.1% for initial COD of 93 and 743 mg·L-1 respectively (diluted and non diluted leachate). Fenton-s oxidation also presented good results for color removal. In spite of being extremely difficult to treat this leachate, the above results seem rather encouraging on the application of Fenton-s oxidation.