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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

PASSIVE AND NATURALIZED LANDFILL LEACHATE TREATMENT SYSTEMS FOR SOURCE WATER PROTECTION

SPEER, SEAN 03 October 2011 (has links)
Landfill leachate production is an unavoidable by-product of landfilling solid waste. Mitigation of the adverse environmental impacts of landfill leachate is required at all active and closed landfill sites. Since leachate production continues long after the landfill is closed and no longer generating revenue, management strategies including low-cost passive and naturalized landfill leachate treatment systems are ideal. The past practice of dumping solid waste into unused tracts of land has created many brownfield sites with uncontrolled discharges of leachate to the receiving environment. Belle Park in Kingston, Ontario is an example of such a site that has been reclaimed for recreational use. A seep management strategy, which included the installation of leachate extraction wells, has been implemented at the site. Passive treatment systems, a coastal fringe wetland and a phreatophyte plots, were installed to evaluate their effectiveness in conjunction with the leachate seep management. Modelling estimated that originally, the pumping wells decreased leachate discharge by 60%, and with the newer wells in 2007 the discharge was decreased by 75- 85%. In situ pilot-scale evaluations of treatments systems are required to ensure adequate treatment of the leachate. The Merrick Landfill in North Bay, Ontario currently captures leachate produced on site and is assessing the potential of a hybrid-passive landfill leachate treatment system. This design process started with bench-scale design and assessment of active pretreatment options, followed by an evaluation of passive and semi-passive treatment systems at the bench-scale (treating 2-3 L/day) at both room (24oC) and cold (2oC) ambient temperatures. The design process culminated with a pilot-scale assessment of hybrid-passive treatment systems (treating 2000 L/d). Assessment of flow in passive treatment system is usually conducted with tracer evaluations. Vertical-flow passive treatment systems with intermittent dosing of leachate for passive aeration have both saturated and unsaturated flow regions. This research shows that tracer evaluation of these types of system was insufficient to measure the clogging within the pore spaces. Therefore a time-lagged flux method was created, based on the pilot-scale hybrid passive treatment system at the Merrick Landfill. This analytical solution quantified the changes in saturated hydraulic conductivity in the treatment system cells. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2011-09-30 15:55:45.73
2

Characterization and treatment of organic matter, UV quenching substances, and organic nitrogen in landfill leachates

Driskill, Natalie Marie 14 June 2013 (has links)
Landfill leachates are often treated on-site before disposal to municipal wastewater treatment plants, although variations in leachate composition and organic loading continue to have negative impacts on downstream treatment processes.  Leachate samples were collected from four landfills both before and after on-site treatment to evaluate the extent of biological treatment. The samples vary in age, location, and on-site treatment processes.  Size fractionation utilizing microfiltration (MF) and ultrafiltration (UF) was conducted in conjunction with TOC, nitrogen species, and UV254 absorbance analysis to determine the characteristics of organic constituents present in landfill leachate.  The size fraction less than 1thousand Daltons (1 kDa) was responsible for a predominant portion of the organic fraction of the landfill leachates studied.  Humic substances are refractory components present in landfill leachates that are resistant to biological treatment and responsible for a portion of the UV quenching ability of leachates.  Humic substances were also fractionated to humic acid (HA), fulvic acid (FA), and hydrophilic (Hpi) components before being subjected to size fractionation to determine UV254 absorbance and organic fractions.  Particle size and hydrophobic-hydrophilic fractionation were conducted in series to evaluate the potential for membrane treatment after biological treatment as a cost effective alternative to reverse osmosis processes currently used to decrease the organic fractions present in landfill leachate.  The organic nitrogen fraction was predominately in the hydrophilic fraction smaller than 1 kDa. / Master of Science
3

Treatment of Landfill Leachate by Integrated Horizontal-Flow Constructed Wetlands

Chen, Yi-ling 13 October 2006 (has links)
Due to various components within the landfill sites, the water qualityof landfill leachate, which has high consistency of COD, BOD and nutrients, is unsteady. Using traditional sewage treatment plant to treat leachate should be designed and built to fit the unsteady water quality, which is usually time consuming and high expenditured. Therefore, application of constructed wetland treatment systems as altanatives may solve such kinds of problems According to the experimental results of this study, referring to the effect of cleaning the controlling substances, the SSF (sub-surface flow system) constructed wetland system performed better than the FWS (free-water surface system) one, which was because FWS was usually operated in an opening water areas, which exposured to the air causing stink in the inflow site of influent, and meanwhile caused problems of virus-transmitting mosquitoes. . Thus, it was suggested to use SSF system in treating landfill leachate. In this study, we found that the average removal efficiencies of pollutants in the leachate were high in the constructed wetland systmes (phosphate 73%, total phosphorous 70¢H, total nitrogen 57%, NH3-N 77¢H, COD 43% ). In addition, the BOD in the effluent from the systems could reach the outflow standard guideline in Taiwan (30 mg/L). Hence, using constructed wetland systems to solve those problems arisen from landfill leachate is expandable. We also found that the aquatic plant species of reed (Phragmites australis) that we used in this study could not grow well and was invaded by aphid due to the limitary environment in the landfill site and lack of biodiversity, which could not generate a good natural food chain. On the other hand, it was found that the plant species of evergreen (Dracaena sanderiana) could grow healthily and present high removal efficiencies for pollutants. Since the leachate was lack of biodegradable organic carbon sources used for denitrification, in the final test run of this study, we run an experiment of adding organic carbon sourcecs (fructose and molasses) into the constructed wetland systemis to test its effect on denitrification. The experimental results showed that the addition of organic carbon sources could significantly increase the efficiencies of denitrification to let more nitrate removed from the leachate, especially for molasses, which could increase the denitrification efficiency above 90%.
4

Exploration of Biological Treatment Systems for the Removal of Persistent Landfill Leachate Contaminants and Nanoparticles

Gomez-Rivera, Francisco January 2011 (has links)
The integrity of groundwater sources is constantly threatened by contaminant plumes generated by accidental gasoline leakages and leachates escaping landfills. These plumes are of concern due to their proven toxicity to living organisms. Aromatic and chlorinated hydrocarbons, volatile fatty acids, phenols, and ammonia have been found in these leachates. In addition, benzene, toluene, and xylenes (BTX) are major components of gasoline. The lack of oxygen in groundwater makes anaerobic bioremediation desired for the treatment of groundwater contaminated with BTX and chlorinated solvents. With the objective of finding microorganisms capable of BTX and cis-dichloroethylene (cis-DCE) degradation under anaerobic conditions for their use in permeable reactive barriers, different inocula were tested in batch experiments. Toluene was rapidly degraded by several inocula in the presence of alternative electron acceptors. Benzene and m-xylene were eliminated by few of the inocula tested after incubation periods ranging from 244 to 716 days. cis-DCE was highly recalcitrant as no degradation was observed over 440 days. Biological processes have been successfully applied for the treatment of landfill leachates as well. In an effort to provide an effective and economical alternative, an anaerobic-aerobic system was evaluated using a synthetic media simulating the organic and ammonia content of real leachates. The removal of the organic content reached 98% in an upflow anaerobic sludge blanket reactor, and resulted in the formation of methane. During the aerobic process, in an innovative down-flow sponge reactor, ammonia was highly transformed to nitrite and nitrate. Complete nitrification was eventually achieved.The capacity of current wastewater treatment plants for removing nanoparticles has been questioned during the last years. Nanoparticles have been incorporated into numerous applications and their presence in wastewater seems to be inevitable. A laboratory-scale secondary treatment system was set-in to study the behavior of cerium and aluminum oxide nanoparticles during wastewater treatment. The nanoparticles were highly removed, suggesting that secondary treatment is suitable for their elimination. The removal of these nanoparticles was influenced by the pH and organic content of the wastewater. Aluminum nanoparticles proved to be toxic; however the performance of the system for eliminating the organic content was recovered over time.
5

Evaluation of landfill leachate treatment using aerobic granular sludge and activated sludge processes

Ren, Yanan 09 March 2017 (has links)
The treatment of synthetic landfill leachate and raw landfill leachate were investigated using two sets of 3 L aerobic sequencing batch reactors (SBR): activated sludge SBR (ASBR) and granular SBR (GSBR). In synthetic young landfill leachate treatment, GSBR was more efficient in nitrogen and carbon removal than ASBR. During the steady period of the experiment, 99% total ammonium nitrogen (TAN) was removed through nitritation and nitrification in GSBR with an average influent TAN concentration of 498 mg/L. On the contrary, complete nitrification was not achieved in ASBR with a nitrification efficiency of 77±10%. GSBR also presented higher efficiency in denitrification and COD removal compared to ASBR. Phosphorus removal efficiency was almost identical in both reactors. Synthetic old landfill leachate treatment using GSBR maintained the stable COD removal efficiency at 66%, when the ammonia nitrogen to the maximum of 465±46 mg/L. The ASBR required a start-up of at least 30 days and removed 59±9% of COD when an influent ammonia nitrogen concentration about 200 mg/L. The GSBR was also more efficient than the ASBR for nitrogen removal. The granular sludge reached a maximum ammonia removal of 95±7%, whereas 96±5% was achieved by ASBR. The phosphorus removal was likely affected by the free nitrous acid (FNA) and the low biodegradability of tannic acid. In raw landfill leachate treatment, the total ammonia nitrogen (TAN) removal efficiency was in GSBR approximately 99.7%. However, the ASBR treatment did not show a consistent performance in TAN removal. TAN removal efficiency decreased with increasing ammonia concentration in the influent. Nitrification in GSBR was partially inhibited at FA concentrations of 48 to 57 mg/L, which was two times more than the FA concentration that inhibited nitrification in ASBR. In terms of chemical oxygen demand (COD) removal, low removal efficiencies of 17% and 26% were observed in ASBR and GSBR, respectively. The low COD removal efficiencies were associated with the refractory organic content of the leachate used in this study, which resulted in a poor phosphorous removal performance as well. Overall, aerobic granular sludge showed a better performance in removing nutrients and organic matter from young or old landfill leachate, being more efficient than the conventional suspended growth activated sludge. Therefore, the use of AGS for leachate treatment should be encouraged. Further investigations should also be addressed, especially with a focus on improving SND and phosphorus removal efficiencies. / May 2017
6

Biochemical characterisation of landfill leachate toxicity in fish

Linderoth, Maria January 2006 (has links)
<p>Deposition remains the most common form of waste disposal in many parts of the world. As a terminus of the products consumed in our society a landfill may contain virtually all sorts of man-made chemicals. Despite this, the harmfulness of landfill leachate has not been extensively evaluated in feral organisms in the environment. In a leachate-contaminated lake, Molnbyggen, in Sweden, our studies reported a low percent of sexually mature (SM) female perch (<i>Perca fluviatilis</i>) that had decreased plasma androgen levels, decreased brain aromatase activity, distinctive sores and fin erosion. The impairments were attributed to unidentified compound(s) present in the leachate. In one out of four other investigated leachate-contaminated lakes, the low percent of SM female perch had reduced plasma sex steroid levels and similar sores as perch in Molnbyggen. The biochemical mechanism causing the disorders was investigated in order to establish a connection between the impairments and possible causative compound(s). Plasma levels of progesterone and 17α-hydroxyprogesterone were unaffected. Ovarian 17,20-lyase activity was decreased while levels of biliary steroid conjugates and hepatic testosterone UDP-glucuronosyltransferase activity did not differ between exposed and reference SM fish. Furthermore, the decreased brain aromatase activity seems to be a secondary effect; possibly a result of low substrate availability. Altogether, this suggests a possible disruption in the synthesis of androgens, knowledge that could be used as a tool in biomarker-directed fractionation studies to pinpoint compound(s). Molnbyggen sediment extracts decreased the testosterone and estradiol concentrations in whole-body homogenates of zebrafish (<i>Danio rerio</i>) after a three week exposure period. This suggests that compound(s) with the potency to alter endocrine function are present in the sediment. Although the first steps have been taken towards identifying compound(s) responsible for this kind of reproductive impairments, they still remain unidentified. Measures have to be taken to identify harmful chemicals in our society, to reduce their number, and to minimise their uncontrolled dispersal.</p>
7

Biochemical characterisation of landfill leachate toxicity in fish

Linderoth, Maria January 2006 (has links)
Deposition remains the most common form of waste disposal in many parts of the world. As a terminus of the products consumed in our society a landfill may contain virtually all sorts of man-made chemicals. Despite this, the harmfulness of landfill leachate has not been extensively evaluated in feral organisms in the environment. In a leachate-contaminated lake, Molnbyggen, in Sweden, our studies reported a low percent of sexually mature (SM) female perch (Perca fluviatilis) that had decreased plasma androgen levels, decreased brain aromatase activity, distinctive sores and fin erosion. The impairments were attributed to unidentified compound(s) present in the leachate. In one out of four other investigated leachate-contaminated lakes, the low percent of SM female perch had reduced plasma sex steroid levels and similar sores as perch in Molnbyggen. The biochemical mechanism causing the disorders was investigated in order to establish a connection between the impairments and possible causative compound(s). Plasma levels of progesterone and 17α-hydroxyprogesterone were unaffected. Ovarian 17,20-lyase activity was decreased while levels of biliary steroid conjugates and hepatic testosterone UDP-glucuronosyltransferase activity did not differ between exposed and reference SM fish. Furthermore, the decreased brain aromatase activity seems to be a secondary effect; possibly a result of low substrate availability. Altogether, this suggests a possible disruption in the synthesis of androgens, knowledge that could be used as a tool in biomarker-directed fractionation studies to pinpoint compound(s). Molnbyggen sediment extracts decreased the testosterone and estradiol concentrations in whole-body homogenates of zebrafish (Danio rerio) after a three week exposure period. This suggests that compound(s) with the potency to alter endocrine function are present in the sediment. Although the first steps have been taken towards identifying compound(s) responsible for this kind of reproductive impairments, they still remain unidentified. Measures have to be taken to identify harmful chemicals in our society, to reduce their number, and to minimise their uncontrolled dispersal.
8

The toxicity of Harmony Landfill Leachate to Green Hydra (Hydra viridiisma)

Ginou, Carrie 01 August 2010 (has links)
Harmony Landfill is a former industrial waste disposal site located adjacent to Harmony Creek in Oshawa, Ontario, Canada. During active disposal, from 1957 until 1980, approximately 1 million tonnes of waste were land-filled at the site. Although past environmental monitoring had indicated localized contamination of ground and surface waters, the current level of impact remained unclear. In order to determine the potential of Harmony Landfill leachate to affect aquatic organisms in Harmony Creek, chemical analysis of field samples and laboratory toxicity testing were performed. Chemical analysis was completed on water samples from Harmony Creek and surface leachate samples collected seasonally at Harmony Landfill. Toxicity tests were conducted using the model freshwater invertebrate Green Hydra (Hydra viridissima). Hydra were pulse-exposed for 24 hours to varying concentrations (0%, 3.2%, 10%, 32%, 100%) of monthly field-collected leachate samples diluted with laboratory water. Population growth, Hydra morphology and survival were recorded daily for 7 days. Results showed that creek waters generally had comparable analyte levels upstream and downstream of Harmony Landfill. Leachate samples contained iron, manganese and zinc at levels which may be toxic to aquatic invertebrates. Population growth was significantly inhibited compared to lab water (0%) controls at the 100% leachate concentration in December 2008 and July 2009. Hydra morphology (32% and 100%) and survival (100%) were also affected by the December 2008 leachate. Findings indicate that leaching is occurring at Harmony Landfill and that the leachate sampled and tested during this research program had the potential to negatively affect Green Hydra (Hydra viridissima). / UOIT
9

BATCH AND BENCH-SCALE FIXED-BED COLUMN EVALUATIONS OF HEAVY METAL REMOVALS FROM AQUEOUS SOLUTIONS AND SYNTHETIC LANDFILL LEACHATE USING LOW-COST NATURAL ADSORBENTS

Li, Chenxi 01 February 2008 (has links)
In this project, three separate experiments were conducted to assess heavy metal removal from metal aqueous solutions and synthetic landfill leachate by adsorption using low-cost natural adsorbents. Fundamental batch investigations indicated that the 4.0-4.75 mm crushed mollusk shells and the Sphagnum peat moss were the best adsorbents for cadmium and nickel removal, respectively. Peat moss was also found to have the highest adsorption capacities for manganese and cobalt adsorption. The adsorption capacities of the peat moss and crushed mollusk shells used as natural adsorbents for the adsorption of cadmium and nickel from binary aqueous solutions in fixed-bed columns under continuous flow conditions were investigated. The life expectancy of each adsorbent in the fixed-bed columns was also assessed for different hydraulic loading rates. The flow rate of 1.5 mL/min (surface loading of 27.52 cm3/cm2•day) and bed depth of 15 cm were identified as the better operational conditions from the column testing. The results indicated that 47.9% and 42.7% cadmium and nickel removal efficiencies could obtained under these operational conditions, respectively. Finally, the peat moss and the crushed mollusk shells were packed in bench-scale down-flow fixed-bed columns to evaluate their adsorption capacities as natural low-cost adsorbents for the removal of heavy metals from aerated and non-aerated synthetic landfill leachate. The flow rate applied in this operation was 1.5 mL/min (surface loading of 27.52 cm3/cm2•day). Peat was found to have the best adsorption capacities in columns treating aerated synthetic leachate for cadmium (78.6%) and nickel (83.8%) removal efficiencies. / Thesis (Master, Civil Engineering) -- Queen's University, 2008-01-31 22:37:34.381
10

Struvite Precipitation of Ammonia from Landfill Leachate

Zhang, Chi January 2016 (has links)
The application of struvite (magnesium ammonium phosphate,!MgNH&PO& ∙ 6H+O) precipitation and its recycling use for the purpose of ammonia removal from both synthetic solutions and landfill leachate were investigated in this study. The results demonstrated that chemical precipitation by struvite formation is efficient for ammonia removal from aqueous solutions. In addition, by recycling the thermal residue of struvite, continuously removing ammonia can technically be achieved. In the struvite precipitation, ammonia removal significantly depended on the pH and chemical molar ratios of NH& ,:!Mg+,:!PO& ./. For synthetic solution (TAN=1,000 mg/L), remarkable TAN removal efficiency of over 98% has been reported when the molar ratio of NH& ,:!Mg+,:!PO& ./ equals 1.0:1.2:1.2, 1.0:1.3:1.3, 1.0:1.3:1.4 and 1.0:1.5:1.5 at optimum pH 9. The optimum combinations of reagents applied in landfill leachate (TAN=1,878 mg/L) were!NH& ,:!Mg+,:!PO& ./ =1.0:1.3:1.3, 1.0:1.4:1.3, 1.0:1.5:1.4 and 1.0:1.5:1.5 at optimum pH 9.5, all of which displayed excellent TAN removal efficiencies of over 99%. Response surface method (RSM) helped to analyze the data and optimize the results. The struvite pyrolysate provided best performance of removing ammonia in both simulated wastewater and landfill leachate at a dosage of 60 g/L, when struvite was previously heated at 105 􀀁 by oven for 2.5 h. In the recycling phase, the struvite pyrolysate resulting from NaOH-mediated pyrolysis was more effective at continuously treating ammonia synthetic solution than was direct heating, with an initial mode of 87.4% at the beginning to 75.1% in the fifth round and direct heating of struvite from 80.9% in the first cycle and 60.6% in the final cycle. The struvite pyrolysate formed by NaOH-mediated pyrolysis performed with greater ability to continuously eliminate ammonia from landfill leachate (97.2% removal at the beginning and 72.3% in the fifth round), than did directly heated struvite (98.4% in the first cycle and 81.3% in the final cycle). Additionally, microwave irradiation could also dissociate struvite, which subsequently demonstrated moderate TAN removal in recycling phases.

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