One of the main environmental problems associated with the disposal of waste on land is the release of liquid emissions from the site. This wastewater, known as leachate, is a product of the biodecomposition of the waste and filtrates from the landfill once the moisture saturation of the fill has been reached. The chemical composition of leachate is variable over time and between sites. Regardless of these variables, the main pollutants of concern in the leachate are ammonia and organics, both of which can cause environmental degradation in relatively low concentrations. Worldwide and in South Africa, leachate has either been directly released into the environment or into the local domestic sewage system. As more has been learned about the human and environmental health risks associated with these disposal methods, there has been a new focus in waste management toward treating the leachate at the source as part of the broader focus of sustainable landfilling. One of the treatment options being used is constructed wetlands (CW) due to the physical and chemical transformation mechanisms in these biological systems. This treatment process has been demonstrated to be effective as a final polishing treatment for leachate, and it is considered a technology appropriate in the South African context. Therefore the aim of dissertation is to ascertain the use of constructed wetlands as an appropriate treatment option for untreated methanogenic landfill leachate by determining the efficiency of ammonia and organic removal in a pilot-scale vegetated submerged bed (VSB) constructed wetland (CW) planted with Phragmites australis. During the 22-week treatability trial the VSB achieved an ammonia concentration removal efficiency of 91% and mass removal efficiency of 87%. Despite this substantial reduction of ammonia, the VSB was unable to achieve the required discharge standard. There were erratic fluctuations in both the treatment efficiencies for COD and BOO, and the results show no evidence of constant reduction of organics during the treatability trials. This is due to the refractory nature and the low biodegradability of the organics that remain in methanogenic leachate as suggested by the low BOO to COD ratio. Due to the low biodegradability of the organics, a biological treatment system, such as a VSB, will not be able to reliably meet the required discharge standards. Other passive treatment options or a combination of systems need to be explored in order to both satisfy legislative requirements and be appropriate in the South African context. / Thesis (M.Sc.)-University of Natal, Durban, 2003.

This study investigated the changes in leachate composition and clogging evolution in leachate transmission pipes and the use of methanogenesis as a leachate treatment alternative for Bioreactor landfills, by using pilot-scale and laboratory studies. The pilot-scale study consisted of a research station built at Brady Road Landfill, housing sixteen HDPE pipes of three different diameters, conveying leachate intermittently at eight different Reynolds numbers, under reasonably controlled conditions. The pipes were tested for leachate degradation, clogging evolution and hydraulic impairment over time. The laboratory studies carried out tested (1) the effect of turbulence intensity and temperature on leachate degradation and clogging effects and (2) biological pretreatment of leachate prior to injection into a bioreactor cell. The pilot study results showed that under the conditions tested, pipes developed a significant amount of organic and inorganic clog material in less than a year of operation. Since limited quantities of fresh leachate (approx. 3 m3) were used during each leachate degradation analyses, the anticipated effects of clogging in a full scale injection system are expected to be more pronounced, which can negatively impact the long-term hydraulic performance, operation, and service life of a Bioreactor Landfill. The first laboratory study showed that increasing the turbulent energy dissipation rate caused greater amounts of CO2 evolution from the leachate, and temperature increase had an impact on dissolved Ca2+ under atmospheric conditions, affecting clog development. The second and third laboratory studies showed that performing leachate methanogenesis reduces organic (COD, VFA) and inorganic (Ca2+, ISS) clog constituents within the leachate However, the rate of methanogenesis was influenced by the ratio of acetate and propionate. It is suggested that if leachate undergoes methanogenesis in a separate leachate digester prior to re-injection into a bioreactor waste cell, it may protect the pipes and other engineered landfill systems against clogging and its detrimental effects, while allowing for CH4 recovery. However, blending of leachates from different wells or cells prior to the methanogenic digester may be needed to balance the variable concentrations and ratios of acetate and propionate over time from different landfill wells and cells.

The thesis examines the causes for the clogging problem of municipal landfill leachate collection system. The main aim of the work is to research clogging processes in different fillings by using municipal waste leachate, evaluate the leachate chemical compound concentration changes, and, based on the results of researches, to maintain the conductivity function. In the graduation thesis, several basic objectives are being solved: to perform column research of the fillings, by using municipal waste landfill leachate, and to identify parameters, identifying the clogging processes of fillings: porosity and porosity coefficient, as well as to analyse their changes; to analyse the concentrations of chemical compounds leachate, having an impact on drainage layer clogging; to evaluate, by applying modelling software, the column filling porosity changes over a period of time. The thesis consist of an introduction, three chapters, general conclusions, list of references used as well as the list of the author’s publication on the dissertation topic. The introductory chapter discusses the study problem, the relevance of the work, presents the description of the research object, formulation of the aim and objectives of the work, description of the research methodology, scientific novelty of the work, the practical significance of results, and defensive statements. The first chapter is the review of literature, as well as examination of: clogging processes in municipal landfill... [to full text] / Disertacijoje nagrinėjama komunalinių atliekų sąvartyno filtrato drenažo sluoksnio kolmatacijos problema. Pagrindinis disertacijos tikslas – ištirti komunalinių atliekų sąvartyno filtrato savybes, kurios apibūdina kolmatacijos procesus drenažo sluoksnyje, surasti tyrimų metu naudojamo drenažo užpildo efektyvią sudėtį, kuri išlaiko laidumo funkciją ir mažiau kenkia aplinkai. Darbe sprendžiami keli pagrindiniai uždaviniai: nustatyti komunalinių atliekų sąvartyno filtrato cheminius elementus, kurie turi įtakos drenažo sluoksnio kolmatacijai, naudojant komunalinių atliekų sąvartyno filtratą atlikti drenažo sluoksnio, kolonėlės tyrimą su skirtingos sudėties medžiagomis ir nustatyti kolonėlių užpildų poringumo pokyčius, nustatyti tinkamą naudojamų medžiagų (skaldos ir smulkintų naudotų padangų) sudėtį drenažo sluoksnio užpildui formuoti. Disertaciją sudaro įvadas, trys skyriai, bendrosios išvados, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašas. Įvadiniame skyriuje aptariama tiriamoji problema, formuluojamas darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai. Pirmas skyrius skirtas literatūros analizei. Šiame skyriuje nagrinėjami kolmatacijos procesai, vykstantys komunalinių atliekų sąvartynuose. Skyriuje apžvelgti pasaulyje atlikti mokslininkų kolmatacijos tyrimai, išanalizuoti gauti jų rezultatai. Skyriaus... [toliau žr. visą tekstą]

Disertacijoje nagrinėjama komunalinių atliekų sąvartyno filtrato drenažo sluoksnio kolmatacijos problema. Pagrindinis disertacijos tikslas – ištirti komunalinių atliekų sąvartyno filtrato savybes, kurios apibūdina kolmatacijos procesus drenažo sluoksnyje, surasti tyrimų metu naudojamo drenažo užpildo efektyvią sudėtį, kuri išlaiko laidumo funkciją ir mažiau kenkia aplinkai. Darbe sprendžiami keli pagrindiniai uždaviniai: nustatyti komunalinių atliekų sąvartyno filtrato cheminius elementus, kurie turi įtakos drenažo sluoksnio kolmatacijai, naudojant komunalinių atliekų sąvartyno filtratą atlikti drenažo sluoksnio, kolonėlės tyrimą su skirtingos sudėties medžiagomis ir nustatyti kolonėlių užpildų poringumo pokyčius, nustatyti tinkamą naudojamų medžiagų (skaldos ir smulkintų naudotų padangų) sudėtį drenažo sluoksnio užpildui formuoti. Disertaciją sudaro įvadas, trys skyriai, bendrosios išvados, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašas. Įvadiniame skyriuje aptariama tiriamoji problema, formuluojamas darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai. Pirmas skyrius skirtas literatūros analizei. Šiame skyriuje nagrinėjami kolmatacijos procesai, vykstantys komunalinių atliekų sąvartynuose. Skyriuje apžvelgti pasaulyje atlikti mokslininkų kolmatacijos tyrimai, išanalizuoti gauti jų rezultatai. Skyriaus... [toliau žr. visą tekstą] / The thesis examines the causes for the clogging problem of municipal landfill leachate collection system. The main aim of the work is to research clogging processes in different fillings by using municipal waste leachate, evaluate the leachate chemical compound concentration changes, and, based on the results of researches, to maintain the conductivity function. In the graduation thesis, several basic objectives are being solved: to perform column research of the fillings, by using municipal waste landfill leachate, and to identify parameters, identifying the clogging processes of fillings: porosity and porosity coefficient, as well as to analyse their changes; to analyse the concentrations of chemical compounds leachate, having an impact on drainage layer clogging; to evaluate, by applying modelling software, the column filling porosity changes over a period of time. The thesis consist of an introduction, three chapters, general conclusions, list of references used as well as the list of the author’s publication on the dissertation topic. The introductory chapter discusses the study problem, the relevance of the work, presents the description of the research object, formulation of the aim and objectives of the work, description of the research methodology, scientific novelty of the work, the practical significance of results, and defensive statements. The first chapter is the review of literature, as well as examination of: clogging processes in municipal landfill... [to full text]

The City of Winnipeg, MB currently hauls by truck the leachate from the landfill, to be co-treated with the municipal wastewater at a wastewater treatment plant. Pre-treating the leachate with physico-chemical methods would allow for direct discharge to the sewer system, avoiding transportation. The goal of this research is to evaluate the effectiveness of different pre-treatment options as well as their impact on a biological nutrient removal system. In Phase I, the four pre-treatment options evaluated were air stripping, chemical coagulation, electro-coagulation and advanced oxidation with sodium ferrate. Chemical coagulation and air stripping reported the best COD and ammonia removal rates, respectively. Phase II evaluated the effectiveness of the selected pre-treatment methods in the response of a biological treatment system. The pre-treatment was successful in allowing complete nitrification by lowering the influent ammonia concentration. However, if the ratio of leachate to wastewater is low enough; pre-treatment may not be needed as the dilution lowers the impact of the leachate’s higher concentrations.

At Degermyran landfill, situated in the municipal Skellefteå, a leachate treatment system was installed in 2005. One of the aims of this study was to investigate how well the treatment system works by using data from chemical measurements made on the leachate before and after treatment. Further this study had the purpose of investigating how the predicted climate changes of the 21st century will affect the amount of leachate generated at Degermyran by using a modified version of Thornthwaites water balance model. The treatment system has the ability of reducing manganese by 90 %, nitrogen by 73 % och TOC by 79 %. By the turn of this century the amount of precipitation that percolates the waste at Degermyran will be between 254 and 298 mm, depending on the amount of greenhouse gases that will be released in the future to come. The conclusions from this study are that the leachate treatment system reduces the levels of the investigated substances and that the amount of leachate produced at Degermyran will increase. To further investigate the efficiency of the leachate treatment system, flow proportionate measurements of the leachate chemistry could be adopted. If accurate flow measurements of the amount of generated leachate were performed the reliability of the used water balance model could be assessed.

Hydrogen is universally known as the most efficient renewable energy source capable of meeting global energy demands. Chlamydomonas reinhardtii has the ability to produce biohydrogen during the metabolic engineering of the photosynthetic pathways. The aim of this study was to 1) use leachate as a feedstock to enhance microalgal biomass and subsequent hydrogen production, 2) use Pulse Amplitude Modulated (PAM) Fluorometry to elucidate the role of photosystem one during hydrogen production, 3) use Nicotinamide Adenine Dinucleotide Phosphate (NADPH) fluorescence as an indicator of hydrogen production and 4) design a modular pilot scale biohydrogen bioprocessing system implementing experimental findings into a conceptual model. This resulted in a cost effective source of renewable hydrogen produced from waste. The use of 16% landfill leachate was found to increase biomass production by 26% as compared to using Tris- Acetate Phosphate (TAP) media alone. Hydrogen induction resulted in an increased gas synthesis of 37% as well as an increased production period of 8 days compared to the normal 5 days. Landfill leachate further reduced the costs as it acted as a free nutrient source with the added ecological advantage of leachate treatment. Hydrogen production was induced by sulphur depletion and physiological parameters were measured using PAM Fluorometry. Photosystem I was found to be dominant during hydrogen production while photosystem II was down-regulated due to the sulphur depletion and damaged D1 proteins. NADPH fluorescence was significantly correlated to hydrogen yields allowing for NADPH to be utilised as a molecular indicator for hydrogen synthesis. The overall functionality of this bioprocessing system relies on the optimum physiological functioning of cells. The above findings were implemented into a pilot scale design, maximising the physiological performance during hydrogen production. This study has contributed knowledge regarding the production of hydrogen gas from leachate, the physiological changes of photosystem I during hydrogen production and the use of NADPH fluorescence as an indicator. The fundamental theories of bioprocessing incorporate a firm understanding of cellular and biochemical processes. The use of molecular indicators determined from physiological studies can be used at pilot scale to improve overall efficiency of hydrogen production. / Ph.D. University of KwaZulu-Natal, Durban 2014.

Abstract Purification techniques for leachate from composting activity - analysis in terms of ammonia nitrogen, total phosphorus and BOD Sofia Lundkvist Leachate from compost facilities has a large impact on the environment if is not properly cleaned. Water samples taken at Ragn-Sells compost facility at Dåva in Umeå have had problems with high amounts of BOD (biochemical oxygen demand), ammonia nitrogen and total phosphorus in their leachate and need to lower these. The aim of this work was to investigate the methods available for treatment of these substances, see if there is a variation depending on spring and autumn in the presence of substances in the leachate from Dåva, and to investigate whether there are methods that can complement Ragn-Sells existing facility for the purification of leachate. Water samples were used to test season-differences of BOD, ammonia nitrogen and total phosphorus. Furthermore, I did interviews with persons from other compost facilities around Sweden to identify alternative methods to reduce the amount of those three substances in leachate from Dåva. There were no clear pattern between measurements in spring and autumn, but the analysis from Dåva shows that there is a statistically significant negative correlation between ammonia nitrogen with average temperature. When the temperature drops the concentration of ammonia nitrogen increases. Further analysis shows that Dåvas existing system likely can be supplemented with additional steps to improve purification of BOD, ammonia nitrogen and total phosphorus, but the data I received was not enough to declare witch method works best for Ragn-Sells as the majority of the persons I came in contact with could not account for the measured values of the three substances.

This study investigated the changes in leachate composition and clogging evolution in leachate transmission pipes and the use of methanogenesis as a leachate treatment alternative for Bioreactor landfills, by using pilot-scale and laboratory studies. The pilot-scale study consisted of a research station built at Brady Road Landfill, housing sixteen HDPE pipes of three different diameters, conveying leachate intermittently at eight different Reynolds numbers, under reasonably controlled conditions. The pipes were tested for leachate degradation, clogging evolution and hydraulic impairment over time. The laboratory studies carried out tested (1) the effect of turbulence intensity and temperature on leachate degradation and clogging effects and (2) biological pretreatment of leachate prior to injection into a bioreactor cell. The pilot study results showed that under the conditions tested, pipes developed a significant amount of organic and inorganic clog material in less than a year of operation. Since limited quantities of fresh leachate (approx. 3 m3) were used during each leachate degradation analyses, the anticipated effects of clogging in a full scale injection system are expected to be more pronounced, which can negatively impact the long-term hydraulic performance, operation, and service life of a Bioreactor Landfill. The first laboratory study showed that increasing the turbulent energy dissipation rate caused greater amounts of CO2 evolution from the leachate, and temperature increase had an impact on dissolved Ca2+ under atmospheric conditions, affecting clog development. The second and third laboratory studies showed that performing leachate methanogenesis reduces organic (COD, VFA) and inorganic (Ca2+, ISS) clog constituents within the leachate However, the rate of methanogenesis was influenced by the ratio of acetate and propionate. It is suggested that if leachate undergoes methanogenesis in a separate leachate digester prior to re-injection into a bioreactor waste cell, it may protect the pipes and other engineered landfill systems against clogging and its detrimental effects, while allowing for CH4 recovery. However, blending of leachates from different wells or cells prior to the methanogenic digester may be needed to balance the variable concentrations and ratios of acetate and propionate over time from different landfill wells and cells.

The present study aimed to determine whether stable isotope techniques can be universally applied to detect landfill leachate contamination in aquatic systems. Results of analysis of ��C in dissolved inorganic carbon ([delta]��C-DIC), deuterium and �⁸O in water ([delta]D-H₂O and [delta]�⁸O-H₂O), and �⁵N of dissolved inorganic nitrogen components ([delta]�⁵N-NH₄⁺ and [delta]�⁵N-NO₃⁻) were presented for leachate, surface, and ground water samples collected from seven landfills located throughout New Zealand between 2003 and 2006. The unique conditions within a landfill lead to measurable fractionations in the isotopic ratios of the products of degradation. Results of isotope and ancillary parameter analyses enabled the discernment of different types of leachate, resulting from different microbial processes within the landfill environment. The isotopic characterisation of leachate enabled improved interpretation of geochemical data from potentially impacted surface and ground waters, and provides useful insight to landfill development for landfill operators. A general isotopic fingerprint delineated by [delta]��C-DIC and [delta]D-H₂O values showed leachate to be isotopically distinct from uncontaminated surface and ground water for samples analysed in the present study. However, not all water samples identified as leachate-impacted via site-specific assessments exhibited isotopic values that overlapped with the general leachate fingerprint. This highlights the need to investigate each site individually, within the context of a possibly global leachate isotope signature. Site-specific investigations revealed the effectiveness of applying [delta]�⁸O-H₂O and [delta]�⁵N-NH₄⁺ or [delta]�⁵N-NO₃⁻, in addition to [delta]��C-DIC and [delta]D-H₂O analyses, to the detection of leachate impact on aquatic systems. Furthermore, ancillary parameters such as alkalinity and ammonium concentration enabled the construction of simple isotope mixing models for an estimate of the quantity of leachate contribution. Results of isotopic investigations of stream biota suggested potential for the development of bio-indicators to monitor leachate influence on aquatic ecosystems in landfill-associated streams. The present study demonstrated the probative power of stable isotope techniques applied to investigations of leachate impact on landfill-associated aquatic systems.