Landfill Leachate Management and Characterization


The Sydney 200 Olympic Games site was previously a highly degraded area affected by industrial activities, landform modification and waste dumping over many decades. Winning the right to host the Olympic Games provided the impetus and funding to consolidate the waste and improve site conditions. During remediation monitoring was put in place to meet NSW State Government licencing requirements and observe impacts from specific activities, particularly construction. In addition, the NSW State Government put aside funds for an Enhanced Remediation Strategy. This strategy was designed to determine the condition of the site as a whole, report data in a user-friendly and useful format and make recommendations for the long term management of the site after The Games.





 



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The legislation of the EU and the Republic of Serbia in the area of municipal solid waste landfill leachate management is not strictly defined. It was systematized through an integrative approach. A complete picture of leachate management was formed by applying relevant legislation in waste management and water management. After completing systematization, the correlation of EU and Serbian legislation was reviewed and accentuated. Finally, advantages of implementing the formed approach were highlighted, at the level of both the EU and the Republic of Serbia. The application of relevant legal documents will allow the establishment of an efficient monitoring system in the period after closing landfill sites, data collecting from the aspect of qualitative and quantitative leachate composition, thereby contributing to the perception of generation and morphology of leachate in this period, and the consideration of technical-technological difficulties in reaching strict limit values for discharging treated leachate into water recipients.

Mostly different activities of solid waste management (SWM) viz. the collection, segregation,
transportation, disposal, processing, recycling and treatment are not effectively
handled and managed in cities and towns in India. The unscientific dumping of
solid waste in the vicinity of city and towns has seriously affected the surrounding
air, soil and water bodies. Today, we are facing with nearly 80 percent of generated
solid waste going unprocessed. This is compounded by rapid urbanization, increased
rural-urban migration and the complexity of waste management in largely unplanned
and expanding cities. Gurugram, a Millennium City located in the National Capital Region
(NCR), Delhi with its dynamic population and constantly evolving infrastructure
is an example of a city that requires concerted efforts from all stakeholders to ensure
that waste is managed in a sustainable manner. While municipal efforts are on track
to achieve the objective of complete scientific solid waste management under the
mission. Stakeholders’ participation is critical to ensure a comprehensive approach
to the same. The focus of the present study is an overview of the existing municipal
solid waste management systems in Gurugram city. The major issues and the feasible
solutions for management of municipal solid waste on sustainable basis have also
been outlined.

The control of environmental pollution and also the treatment of polluted water are of great concern. Within the past decade, electrochemical coagulation process has emerged as most effective wastewater treatment process as compared to conventional techniques of treating wastewater. Electrocoagulation is robust, cost effective, reliable, low sludge generating process, it has automation amenability and it has high pollutant removal efficiency. It has been proved effective in treating various types of wastewater but is seldom accepted. The aim of the review is to explain the basics and up to date advancement of electrocoagulation method for the improvements in the pollutant removal efficiency. In this review paper, an overview of electrocoagulation method with effect of key operational parameters on it is provided. Limitations of the method are also represented for the better understanding of the mechanism of pollutant removal and its optimization. The recent advancements and future scope of the electrocoagulation process are also reviewed.

Municipal solid waste management (MSWM) has become one of the significant
environmental issues, particularly in developing countries. Bengaluru, the
state capital of Karnataka, is one of the fastest growing cities in Asia. The Bruhat
Bengaluru Mahanagara Palike (BBMP) with an area of 2190 km2 and a population
of about 10.18 million generates around 5000 metric tons per day of solid waste
at an average generation rate of 0.5 kg per capita per day (kg/capita/d). Presently,
Bengaluru City is facing significant problems due to existing disposal practices of
generated waste, incurring high cost due to lack of proper infrastructural facilities;
also, the open dumping in the expanding zone of the city poses severe problems
to the structures constructed on these old dumps. In the meantime, groundwater
quality deteriorated due to improper leachate management. Intending to assess the
possible impacts on the water environment and suggest a better waste management
strategy, the present paper discusses the potential for handling the wastes, thereby
reducing the amount of waste to be transported to the landfill. If this waste is used
for energy and nutrient recovery, decentralization could also become commercially
viable and address the technology-wise deficiencies in the existing MSWM system
of Bengaluru City.

A major environmental impact of waste landfilling is the contamination caused by generated leachate. Leachate is the contaminated water that drains from a landfill. Water, during its passage through a landfill, extracts both soluble and suspended solids in the forms of dissolved and particulate organics and inorganics including heavy metals, xenobiotic compounds, and ammonium ions. Further, the composition of leachate dependent upon the age and type of waste contained making treatment major engineering challenges today. Leachate in general is characterized by high COD (6000-60000 mg/L), BOD (4000-13000 mg/L), NH4-N (500-2000 mg/L) and varying BOD/COD ratio (0.1-0.7). Limiting leachate generation is the most desirable option to control but total elimination of generation is almost impossible. Leachate treatment using biological methods; oxidation ponds (OP), sequencing batch reactors (SBR), activated sludge (AS) and up flow anaerobic sludge blankets (UASB) is well documented for ammonia and organics removal. However biological treatment options show less effective in treating mature leachate than young leachate. Among biological methods, the AS, UASB, and SBR have shown over 90% COD removal and over 80% ammonia removal with 3500-25000 mg/L and 100-1000 mg/L initial COD and ammonia concentrations respectively. Among physicochemical methods in practice, activated carbon adsorption, chemical precipitation and reverse osmosis (RO) are widely applied. According to reviewed studies and applications, combined biological and physicochemical systems are the best for treating lechate. For an example AS with RO has shown almost total COD and NH4-N removal. This paper critically reviews the documented technologies for leachate treatment in respect to treatment efficiencies, advantages, and drawbacks of each.

Landfill leachate is characterised by high chemical and biological oxygen demand and generally consists of undesirable substances such as organic and inorganic contaminants. Landfill leachate may differ depending on the content and age of landfill contents, the degradation procedure, climate and hydrological conditions. We aimed to explain the characteristics of landfill leachate and define the practicality of using different techniques for treating landfill leachate. Different treatments comprising biological methods (e.g. bioreactors, bioremediation and phytoremediation) and physicochemical approaches (e.g. advanced oxidation processes, adsorption, coagulation/ flocculation and membrane filtration) were investigated in this study. Membrane bioreactors and integrated biological techniques, including integrated anaerobic ammonium oxidation and nitrification/denitrification processes, have demonstrated high performance in ammonia and nitrogen elimination, with a removal effectiveness of more than 90%. Moreover, improved elimination efficiency for suspended solids and turbidity has been achieved by coagulation/ flocculation techniques. In addition, improved elimination of metals can be attained by combining different treatment techniques, with a removal effectiveness of 40-100%. Furthermore, combined treatment techniques for treating landfill leachate, owing to its high chemical oxygen demand and concentrations of ammonia and low biodegradability, have been reported with good performance. However, further study is necessary to enhance treatment methods to achieve maximum removal efficiency.

Percolating water passing through waste becomes contaminated and will have dissolved soluble organic and
inorganic compounds as well as suspended particles. Also the pore fluid of the waste is often released and mixes
with this water. The entire contaminated fluid is called leachate. There are many factors that affect leachate
production like annual precipitation, runoff, infiltration, evaporation, transpiration, and freezing, mean ambient
temperature, waste composition, waste density, initial moisture content, and depth of the waste fill. The production
of leachate reduces when a landfill is closed. The decomposition of waste in presence of water can be separated into
two different phases of degradation viz., initial aerobic and subsequent anaerobic. Generally, the leachate undergoes
natural chemical changes over time that reduces its toxicity. Some of the soluble contaminants enrich the water
table, or the saturated zone. Some of remaining molecules naturally adsorbed to the clay liner particles. The paper
discusses the characteristics of leachate generated from municipal solid waste landfill and its effect on surrounding
water bodies near Mavallipura landfill area in Bangalore. Two samples of water from the nearby pond and well were
collected from downstream of Mavallipura landfill site. Physico-chemical characterization of leachate has shown
that the leachate contains high concentrations of organic and inorganic constituents beyond the permissible limits.
While the heavy metals concentration was in traces as the waste is dumped in the landfill is mainly domestic in
nature. The pH of the leachate is marginally alkaline as the pH is 7.4. The results also showed that the highest metal
concentration that exists in the leachate was Iron which is about of 11.16 ppm. BOD5 and COD of the leachate are
1500 mg/l and 10400 mg/l, respectively. The leachate characteristics indicate favorable growth of algae in natural
water contaminated with leachate with the alkaline condition and with the presence of magnesium as nutrient, which
has been confirmed in the nearby surface pond. Knowledge of leachate quality will be useful in planning and
providing remedial measures to protect surface and ground water quality in the area.

Abstract: The aim of this research is to evaluate transport of pollutants from a sanitary landfill leachate through a Brazilian lateritic soil by two methods: laboratory tests and analysis of field contamination.
In Botucatu Sanitary Landfill, leachate stored in an unlined pond infiltrated into the subsoil for 15 years. Samples of the subjacent soil, a porous clayey sand, were collected in three profiles located inside the area of the leachate pond at the following depths: surface, 0.25 m, 0.50 m, 1.00 m, 2.00 m and 4.00 m. The investigated pollutants were arsenic, cadmium, chloride, cooper, iron, lead, manganese, nickel, Kjeldahl nitrogen, total organic carbon (TOC) and zinc. 
The hydraulic conductivity measured in undisturbed and uncontaminated samples of the local soil, around 10-6 m/s, is significantly influenced by the applied hydraulic gradient and the percolation duration. When leachate substituted water as percolation fluid, the hydraulic conductivity decreased to values between 10-8 and 10-6 m/s depending on the hydraulic gradient.
Chemical analysis of contaminated samples showed that concentrations of the researched elements in the subsoil were lower than legal maximum contamination limits established by the environmental agency of São Paulo state, in spite of the fact that the local soil is porous and has high hydraulic conductivity. On the other hand, chloride and Kjeldahl nitrogen, pollutants for which there are no legal limits, were found in concentrations much higher than background values, and in some samples even higher than those measured in the leachate sludge deposited in the bottom of the storage pond.

Resumo: Esta dissertação de mestrado tem como objetivo principal avaliar o transporte de poluentes de um lixiviado real de aterro sanitário em um solo laterítico do estado de São Paulo. A pesquisa objetiva também comparar dois métodos de avaliação de transporte de poluentes: ensaios laboratoriais e análise de dados de contaminação de campo.
No aterro sanitário de Botucatu houve, comprovadamente, percolação do lixiviado pelo subsolo durante aproximadamente 15 anos, sob uma lagoa de acumulação de lixiviado sem revestimento de fundo. Foram coletadas amostras de solo subjacente à lagoa, uma areia argilosa, em três perfis verticais na superfície e nas profundidades de 0,25 m, 0,50 m, 1,00 m, 2,00 m e 4,00 m. Os poluentes investigados foram: arsênio, cádmio, carbono orgânico total (COT), chumbo, cloreto, cobre, cromo, ferro, manganês, níquel, nitrogênio Kjeldahl total (NKT) e zinco.
Amostras indeformadas do solo local não contaminado foram também coletadas para ensaios de permeabilidade à água e ao lixiviado, assim como para ensaios de coluna. A condutividade hidráulica do solo é da ordem de 10-6 m/s, porém significativamente influenciada pelo gradiente hidráulico aplicado e pela duração da percolação. A condutividade hidráulica diminuiu com a percolação de lixiviado para ordens de grandeza entre 10-8 e 10-6 m/s, dependendo do gradiente hidráulico. Os ensaios de coluna mostraram concentrações efluentes dos elementos pesquisados superiores às afluentes, impossibilitando a obtenção de parâmetros de transporte de poluentes.
A análise das amostras contaminadas coletadas in situ mostrou que, embora o solo local seja poroso e apresente alta permeabilidade, as concentrações dos elementos estudados eram inferiores aos limites legais de contaminação do órgão de controle ambiental estadual. O cloreto e o nitrogênio, para os quais não há limites legais, apresentaram-se no subsolo em concentrações elevadas, superiores às concentrações no solo natural e, em algumas amostras, às do lodo depositado no fundo da lagoa.

Urbanisation has been characterised by unsustainable impacts such as depletion of natural resources, increased pollution, increased volume of surface runoff , decreased quality of storm water and destruction of aquatic life and biodiversity. Studies have shown that Sustainable Drainage Systems (SuDS) would help mitigate some of these effects. However, sustainability of some SuDS devices is questionable because their component parts involve the use of natural resources, i.e., topsoil and gravel.The overall aim of this study was to evaluate the efficacy of the application of recycled/waste materials in performing at least as well as topsoil and gravel in vegetative SuDS, thereby improving water quality and the overall sustainability of the devices. The materials investigated were compost and recycled aggregates with topsoil and gravel as control. Compost used included green compost and mixed compost while recycled aggregates comprised of crushed old and new bricks, as well as recycled limestone aggregates. Methodology included baseline characterisation of the materials followed by leaching experiments with heavy metals and motor oil, biomass determination and microbiological assessments.Application of recycled aggregates was shown to be more sustainable in terms of conserving natural resources, compared to topsoil and gravel. Results showed that compost would significantly biodegrade organic pollutants in vegetative SuDS under varying conditions, compared to topsoil. Also, vegetative growth in profiles containing compost was significantly more prolific than those with topsoil alone. Compost and recycled aggregates performed as well as gravel and topsoil in remediating pollutants, with >98% of pollutants being retained mostly within the growth media. This highlights the potential application of recycled aggregates and compost in SuDS devices which could reduce cost and provide use for used materials, which could have been disposed of in landfills or brownfields with huge negative environmental impacts.

Keywords: Vegetated SuDS, Recycled Waste, Compost, Recycled Aggregates, Stormwater Pollution

Access: https://novapublishers.com/shop/stormwater-sources-monitoring-and-management/

Landfill leachate consists mostly of a high content of refractory organic matter, ammonia and toxic compounds. All of these compounds, regardless of their nature, have a potential pollution effect on local ground and surface waters. In this context, the purpose of the present study was to evaluate a treatment process (coagulation-flocculation with lime coupled with nanofiltration) applied to landfill leachate from Seropédica, Rio de Janeiro (Brazil). Jar tests were conducted to determine the optimum dosage of lime (ranged from 0 to 10 g L-1) and, at optimum lime dose, ammonia nitrogen was removed during coagulation-flocculation process due to high pH. The process was settled for 6 h with slow stirring (50 rpm) to promote air entrainment and NH3-N stripping before using the final treatment step of nanofiltration at 8 bar. After ammonia stripping, NH3-N was reduced from 1236 mg.L-1 to 353 mg.L-1 (71% removal efficiency). At the end of the combined treatment, TOC (Total Organic Carbon), HS (Humic Substances) and COD (Chemical Oxygen Demand) removals were 89%, 80% and 94%, respectively. The results showed that the combined process was effective in the removal of recalcitrant compounds and NH3-N.

Studies have shown that urban and rural waste management has been a serious problem in Nigeria. This work aims at investigating the effect of waste dumps on the groundwater in Odolomi area of Supare Akoko, south-western Nigeria using resistivity sounding method (dipole-dipole) and laboratory water sample analysis.
Ten (10) hand-dug well water samples and one (1) spring water sample which serves as a control were collected in the study area and analyzed for hydrogeochemical and microbial characteristics to know their quality and usability. The result of the analysis shows that elements like K, Na, Ca, and Pb are found in excess in the groundwater of the study area and more so, there is presence of micro-organisms like Enterococci, Coliform in the study area. The result of the analysis was then compared to the WHO (2010) standard for drinking water and it is evident that the groundwater is contaminated. The geophysical investigation shows that the area is highly conductive which implies that the water in the area is susceptible to contaminations.
It is evident that the study area is contaminated and not potable. This calls for necessary treatment and advanced water scrutiny

The treatment of high-strength petroleum refinery effluent (PRE) with [BOD5]/[COD](0) = 0.14 was investigated using combined Fenton-sequencing batch reactor (SBR). The effect of [H2O2]:[COD](0) molar ratio on biodegradability enhancement was investigated. Fenton optimal conditions were: [H2O2]:[COD](0) of 6, [H2O2]:[Fe-0] of 10 and pH = 3.0 that could remove 76.5%, 45% and 96% of COD, TOC and phenol and increased biodegradability ratio to 0.37. The pretreated PRE subjected to SBR for one single cycle of 10 h. The results revealed the effectiveness of hybrid Fenton-SBR system in treating PRE where the complete treatment of the PRE was attained by this system. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Link to full text articles :
http://www.sciencedirect.com/science/article/pii/S1226086X1400522X 
http://ac.els-cdn.com/S1226086X1400522X/1-s2.0-S1226086X1400522X-main.pdf?_tid=4d49b94a-4011-11e5-b09d-00000aab0f01&acdnat=1439288056_0daf270234cb91a5c805cd234e5478be

The physicochemical characteristics and heavy metal levels of leachates at the Rumuodumaya dumpsites and the surface water of its adjacent river was investigated by appropriate field instrument for in situ measurement, standard procedures and AGILENT 55B spectra for the heavy metals. The results from the dumpsites and surface water of the river generally indicate that as of the time of analysis, there is no serious threat to its immediate environment except the nickel concentrations in the dumpsites and surface water of the river, respectively and whose values were beyond the recommended limit of WHO/USEPA (0.05 mg/L) for safe drinking water. The trend of the results also indicates that the dumpsites are sources of numerous soil and water pollutants capable of depleting oxygen levels in the river and this could pose several and serious health risk to humans and aquatic life. Adequate solid waste disposal technique should be adopted by the appropriate agency to forestall this threat to the Rumuodumaya environment.

In this study, characterization and electrocoagulative treatability of nanofiltration concentrate from a full-scale landfill leachate treatment plant (Istanbul, Turkey) were investigated. The average concentrations of COD, TKN and ammonia were determined as 6200, 587.5, and 110 mg/L, respectively. Membrane concentrate also have almost neutral pH, high conductivity and color. Besides, nanofiltration concentrate contains low metal concentrations. After the characterization of the concentrate, treatment of the concentrate by electrocoagulation method with aluminum plate electrodes was investigated. The effects of electrode type, current intensity and treatment time on the treatment of nanofiltration concentrate by EC process were investigated. According to the results, the most acceptable current intensity for COD, color, and phosphorus removal was determined to be 15.9 mA/cm 2 and the most acceptable treatment time was determined to be 30 min. The treatment efficiencies for COD, color, and phosphorus at 15.9 mA/cm 2 and 30 min were determined as 45%, 60%, and 91.8%, respectively. According to the results of this study, EC process may be an acceptable solution for the treatment of leachate nanofiltration concentrate. More detailed studies however need to be done for the determination of the optimum operational parameters of the electrocoagulative treatment of membrane concentrate.

Large volumes of chromated copper arsenate (CCA)-treated wood are disposed of in lined and un-lined landfills across the world. Studies regarding the disposal and reuse of CCA-treated timber date back to the 1980s. This paper provides a comprehensive overview of the research undertaken regarding reconstituted chromated copper arsenate-treated timber products, and considers the relevant health issues and disposal techniques, such as incineration and thermochemical conversion, as well as long-term solutions for the managing of chromated copper arsenate-treated-waste wood. The results from reviewing the literature regarding reconstituted timber products consisting of CC-treated timber such as particle board, cement-bonded particle board, flake board, remediated wood composites, wood-plastic composites, and wood-cement composites revealed that products such as particle board, wood-plastic composites and flake board composed of CCA-treated timber show considerable promise. Further research is required to determine the optimum percentage of CCA-treated timber in wood-plastic composites to minimize leaching while attaining suitable physical and mechanical performance, and to evaluate the durability of reconstituted chromated copper arsenate timber products via severe accelerated aging tests. Several CCA-waste wood disposal methods were investigated in the form of extraction and destruction techniques including thermochemical conversion (pyrolysis, gasification), incineration, co-incineration and combustion. Such management techniques demonstrate promising, feasible, future solutions providing the ability to trap arsenic gas, recover metals, and create secondary energy forms. However, more research is required, especially regarding resultant arsenic compounds and their volatile behaviours. Industries that create and sell chromated copper arsenate-treated wood products are encouraged to follow the United States Environmental Protection Agency leachate testing procedures (Methods 1314 and 1315, published in 2013), since these methods are more accurate at evaluating the leaching behaviour during their lifetime, and various disposal scenarios that reflect differing pH values and liquid to solid ratios.

Landfill leachate is a medium affected by a considerable number of factors, both within the landfill body (landfill age, the morphological composition of waste, temperature and moisture content, landfill fluid migration, waste treatment technologies before disposal, landfill body thickness, waste decomposition phases), and outside (meteorological parameters, with an emphasis on annual precipitation). The variable and almost unpredictable qualitative composition of leachate from municipal solid waste landfills, which often includes emerging substances, such as antibiotics and endocrine disruptors, as well as heavy metals, significantly affects the structure and diversity of the present microbiological communities. By implementing leachate sampling campaigns in the winter, spring, and autumn in 2019 at three non-sanitary (L1, L2, L3) and one sanitary (L4) municipal solid waste landfills in the region of Vojvodina, the presence of microorganisms Escherichia coli, Klebsiella pneumoniae and Citrobacter freundii, Gram-negative bacteria from the family of Enterobacteriaceae, in the phylum Proteobacteria, were detected. Due to the frequent causing of urinary, extraintestinal, diarrheal, and respiratory infections, meningitis, colitis, sepsis, as well as high resistance to a range of antibiotics, Gram-negative bacteria may represent a potential risk to human and animal health, under specific exposure circumstances. In addition to the use of Gram-negative bacteria Escherichia coli, Klebsiella pneumonia, and Citrobacter freundii as indicators of fecal contamination, the potential of the use of the mentioned bacteria as indicators of contamination of leachate with heavy metals and organic compounds, as well as the functionality and condition of municipal solid waste landfills.

This paper presents the findings of a study carried out in Phnom Penh city, Cambodia, on the basis of commercial solid waste. The waste samples were collected from hotels, restaurants, internet cafés, guesthouses, beer gardens, markets, schools, microfinances and shops from 22 July–28 August 2013. The objectives of this research are to determine waste generation rate, physical composition, and the level of recyclables remaining in the residual of waste stream and to evaluate the appropriate technology for waste treatment. The waste from 52 commercial sectors were daily collected and segregated into 23 categories. The results show that composition of commercial waste consist of 56.70% (biodegradable), 19.32% (plastic), 14.84% (paper), 8.14% (inorganics), 1.25% (textiles & shoes), 0.25% (rubber/leather), and 0.01% (wax). Waste generation rate (kg/cap/day) is 1.31
(internet cafés), 1.04 (restaurants), 0.84 (beer gardens), 0.51 (guesthouses), 0.33 (hotels), 0.23 (markets-family marts), 0.19 (ministries), 0.13 (council of ministers) and 0.11 (stores-phone, grocery and small cloth shops). In addition, schools and microfinance agencies produce waste less than 0.1.The most sorted wastes by those sectors are food waste, followed by glass bottle, paper, PET bottle, aluminium can and steels. The most recyclable remaining in unsorted waste is plastic, followed by paper, steels and aluminium can. Finally, treatment options for organic waste from commercial sectors in Phnom Penh were discussed.

Geo-Electrical investigation of the effect of pollution was carried out at a dumpsite in Kubwa, under Bwari area council, FCT, Abuja,with the aim of determining how accurately electrical measurements could delineate the influx of leachate into soil and groundwater. The result of the Geophysical investigation was correlated with the Physiochemical analysis of water samples on and around the dumpsite which shows that the study area is highly contaminated by leachate. The ABEM SAS 4000 was used to accomplish this task. Thirty Vertical Electrical Sounding measurements were taken on and around the dumpsite using Schlumberger array Configuration. Five profiles were covered and the data were processed to display the variations of electrical resistivities using the RES2DINV software. The subsurface was classified into 3 to 4 geoelectric layers and the fourth layer harbouring most of the aquiferous zones which is delineated as being more conductive and less resistive than the overlying layers. The topsoil, which consists of reddish brown lateritic and sandy clay, has resistivity values between 58.2Ωm and 908.8Ωm and its thickness between 0.8m to 3.7m. The depth of this layer is 0.3m to 4.6m. The second layer, is the weathered basement, and has resistivity values 142.1Ωm to 1470.3Ωm. Its thickness is 5.4 m to 94.5m. The depth of this layer is 7.5m to 95.6m. The resistivity of the fractured basement which forms the third layer is 42.3Ωm to2319.9Ωm. Its thickness is 37.2Ωm to 87.3Ωm. The depth of this layer is 46.4Ωm to 118.2Ωm. The resistivity of the fresh crystalline basement which forms the fourth layer is 21.5Ωm to 1325Ωm. Its thickness is 68.5Ωm to 92.7Ωm. The depth of this layer is 123.2Ωm to 126.5Ωm.

Leachate is known to be hazardous wastewater in terms of its organic matter and ammonia content. Various methods have been studied extensively for the treatment of different types of leachate. However, scheduled waste leachate is rarely studied due to its complex characteristics and highly contaminated nature compared to other types of landfill leachates. In this study, hydrated lime (Ca(OH)2) and caustic soda (NaOH) as softener agent were used for increasing the pH of the treatment process of scheduled waste leachate to remove ammonia-nitrogen (NH3-N). Chemical oxygen demand (COD) and colour removal were also evaluated. Jar test experiments was performed using Ca(OH)2 and NaOH at varying dosages ranging from nil to 12 g L-1. A Historical Data Design (HDD) of Response Surface Methodology (RSM) was employed to optimize the parameters affecting NH3-N, COD and colour removal efficiency. The optimal conditions obtained from desirable response were predicted at 5.9 g L-1 of Ca(OH)2 dosage, where the maximum NH3-N, COD and colour removal efficiency would be 49%, 18% and 66%, respectively. Meanwhile for NaOH, dosage of 6.4 g L-1 was predicted to remove NH3-N, COD and colour up to 32%, 4% and 42%, respectively. The predicted values concurred with the experiments, in which Ca(OH)2 successfully reducing NH3-N, COD and colour up to 52 %, 17.5 % and 65 %, while NaOH could only remove NH3-N, COD and colour by up to 35 %, 2 % and 49 %, respectively. The results obtained from this study suggest that hydrated lime (Ca(OH)2), is more feasible to be used for the pre-treatment process of scheduled waste leachate as less dosage is required with higher removal efficiencies of NH3-N, COD and colour. This study demonstrates that RSM was a reliable tool to predict the optimum dosage and suitable types of chemicals for the removal of NH3-N, COD and colour from the available data.


Air larut resap dikenali sebagai air sisa yang berbahaya dari segi kandungan bahan organik dan ammonia. Pelbagai kaedah telah dikaji secara meluas untuk merawat pelbagai jenis air larut resap. Walau bagaimanapun, air larut resap sisa terjadual jarang dikaji kerana ciri-ciri kompleks dan mengandungi bahan yang sangat tercemar berbanding air larut resap tapak pelupusan yang lain. Dalam kajian ini, kapur terhidrat (Ca(OH)2) dan soda kaustik (NaOH) sebagai agen pelembut telah digunakan untuk meningkatkan pH proses rawatan air larut resap sisa terjadual untuk menyingkirkan ammonia-nitrogen (NH3-N). Permintaan kimia oksigen (COD) dan penyingkiran warna juga telah dinilai. Eksperimen ujian jar telah dilakukan dengan menggunakan Ca(OH)2 dan NaOH pada dos yang berbeza-beza antara sifar hingga 12 gL-1. Rekabentuk data

Landfill leachate (LFL) collected from the controlled discharge of Jebel Chakir in Tunisia was treated without any physical or chemical pretreatment in an anaerobic membrane bioreactor (AnMBR). The organic loading rate (OLR) in the AnMBR was gradually increased from 1 g COD l−1 d−1 to an average of 6.27 g COD l−1 d−1. At the highest OLR, the biogas production was more than 3 volumes of biogas per volume of the bioreactor. The volatile suspended solids (VSSs) reached a value of approximately 3 g l−1 in the bioreactor. At stable conditions, the treatment efficiency was high with an average COD reduction of 90% and biogas yield of 0.46 l biogas per g COD removed.

This study investigated the effect of landfill leachate on biomass and biohydrogen production from Chlamydomonas reinhardtii. Maximum biomass and cell viability was recorded in 16% leachate medium with a corresponding growth rate of 927 µg/L chl a d-1 as compared to the control of 688 µg/L chl a d-1. Chlamydomonas cultured in leachate-supplemented medium was subsequently induced to produce 37% more biohydrogen compared to the control culture. The spurge in growth can be a consequence of abundant essential elements in the diluted leachate. Energy Dispersive X-ray analysis of cells in a 16% leachate medium had the highest accumulation of Cr, Mn, Fe, Co, Ni, Mo and Cd. The benefits of the leachate medium were further shown during the hydrogen production phase using Pulse Amplitude Modulated Fluorometry. This period was extended to 8 days in comparison to the control. Leachate therefore increases both the biomass and biohydrogen yield of Chlamydomonas.

Some landfills receive waste sources such as foundries, incinerators or similar sources which contain oxidizing elements and generate extremely high temperatures in landfill. Leachate from these landfill (Elevated Temperature Landfills, ETLFs or ET landfill) exhibit very high levels or BOD, COD and other contaminants which are difficult to treat. This paper describes a process by which the levels of these parameters are reduced from around 70,000mg/l and 40,000 mg/l to around 5000 mg/l and 2000 mg/l, respectively.

Chromated Copper Arsenate (CCA) is a popular wood preservative applied to wood products to prevent environmental decay during outdoor use and hence has been predominant in the disposal sector in recent years. Estimates suggest that some CCA- treated wood waste in Florida is burned to produce energy. Incineration results in volatilization of metals during combustion and an accumulation and subsequent leaching of metals in the ash. This poses health and environmental concerns. Past studies have shown that many mineral sorbents are effective in controlling heavy metal volatilization in air phase during incineration. The objective of this study was to evaluate the viability of thermal processes in existing facilities as an option for the management of CCA wood waste in the state of Florida.

Three tasks were carried out to assess the use of existing wood-fired capable facilities as a viable option for the management of CCA wood waste. In the first task, an inventory of existing wood-fired capable facilities and their pollution control devices was compiled. This inventory included two categories: facilities using wood as their fuel and others (such as cement kilns, waste to energy (WTE) plants, coal fired boilers etc.) that can possibly be converted to burn wood. In Florida, amongst the facilities belonging to these categories, the maximum capacities corresponded to wood-based facilities, followed by WTE facilities and coal-fired plants with cement kiln boilers representing the smallest available capacity. While wood boilers also use a variety of carbonaceous fuels, cement kilns and coal fired plants primarily run on coal and use some secondary fuels as well. WTE facilities used municipal solid waste (MSW) for combustion. A variety of air pollution control devices are found in each facility depending on the types of air emissions at that facility. In terms of the maximum heat input rate/ heat capacity of the combustion boilers, coal fired power plants had the highest median heat capacity followed by cement kilns, wood boilers and WTE facilities.

In the second task, a literature survey was conducted on available pollution control technologies and equipment for controlling arsenic emission and leaching resulting from the incineration process. From the survey results, co-incineration appears to be the most promising technology amongst the existing techniques in the short term. Long term options for disposal of CCA treated wood by thermal processes need to be evaluated. Coupling co-incineration with sorbent injection in feed and gas stream can result in the dual benefit of controlling submicron particulate emissions as well as forming non-toxic, non leachable ash which can be disposed of easily. An evaluation of the existing options suggests that the use of a combination of air pollution control devices, e.g., using a wet scrubber combined with an ESP or a baghouse seems to be the best available technique to control arsenic emissions. Injection of mineral sorbents in the flue gas followed by capture of particulates using a baghouse or an ESP has been successful
in controlling arsenic emissions in coal combustion and can be applied to wood waste too. Amongst the various techniques available for sampling of arsenic in ambient air, impregnated filters appear to have the highest particulate and vapor capture efficiency.

In the third task, potential mineral materials that can prevent arsenic leaching from incineration products were screened in laboratory studies. Experiments were conducted to evaluate various sorbent materials for their capability in reducing ash leachability as well as to characterize the crystalline speciation of the reaction products. Experiments were carried out using metal spikes with quantities equivalent to 3.68 pounds per cubic feet (pcf) of CCA-treated wood (treated with CCA type C chemical). The spike-sorbent samples were heated at 700 oC, 900 oC and 1100 oC for 30 minutes. A portion of the residual was leached using the toxicity characteristic leaching procedure (TCLP). X-Ray Diffraction (XRD) analysis of the residue was conducted to determine the crystalline speciation of the products. Amongst the various sorbents tested in the given temperature range, the alkaline earth sorbents (cement, calcium hydroxide and magnesium hydroxide) and ferric oxide (at 1100 oC) showed the greatest promise in reducing the leaching of arsenic to significantly lower values than the TC limit of arsenic from the incinerator ash. Regarding chromium, the alumino-silicate group (alumina and silica at all temperatures, and kaolin at higher temperatures), ferric oxide and magnesium hydroxide (at 1100 oC) leached less than the TC limit of chromium from the ash. For copper, all sorbents displayed low leaching values. Volatilization of metals was also reduced due to the metal-sorbent binding, up to 60% in some cases, depending on the type of sorbent used and the system temperature. Speciation characterization results reveal the formation of several metal-metal and metal-mineral compounds (e.g. insoluble Ca3(AsO4)2 and highly soluble CaCrO4). The formation of these compounds may have resulted in different leaching behavior of each metal-sorbent pair under different combustion conditions.
Potential practical scale applications of sorbent technology for thermal conversion of CCA treated wood have been proposed based on these results. At high temperatures (>1000 oC), most of the arsenic is found in the gas phase while chromium and copper remain in the feed. Hence, a strategy to control the leaching of metals can possibly be developed based on these studies. A single sorbent or a combination of sorbents can be used to effectively control the leaching of CCA metals, e.g., using cement in the flue gas to capture arsenic and any alumino-silicate sorbent or ferric oxide in the feed to capture chromium and copper. Another possible alternative could be using ferric oxide or magnesium hydroxide at high temperatures (~1100 oC) to capture all three CCA metal simultaneously, both in feed and gas phase. Based on this strategy, cement kilns, coal combustion plants, MSW incinerators and steel mills may be potentially viable options for disposal of CCA-treated wood by co-incineration.

FeCl 3 coagulation was used to achieve maximum reduction of COD, phosphate, sulfate and color and process optimization (FeCl 3 dosage, pH, reaction time) was done by BBD-RSM. Responses were recorded in terms of EC, COD, phosphate, color and sulfate removal. Variables A (pH) and B (reaction time) were negatively related to removal of COD and phosphate, whereas, C (FeCl 3 dosage) was positive in case of COD removal and negative for phosphate removal. pH and coagulant dosage had negative relationship with color removal; however, reaction time showed positive relationship. In case of percent sulfate removal, variable A (pH) demonstrated negative relationship whereas B (reaction time) and C (FeCl 3 dosage) were found to be positively related. Numerical optimization of the model revealed a maximum reduction of 71, 93, 86 and 99.6 % COD, phosphate, color and sulfate at optimal FeCl 3 dosage = 3 g/l, pH 8, and reaction time = 95 min.

The effects of salinity on anaerobic waste degradation and microbial communities were investigated, in order to propose an appropriate leachate recirculation process in a waste landfill in a tropical region. A salt concentration of 21 mS cm À1 of electrical conductivity (EC) did not affect waste degradation, but a salt concentration of 35 mS cm À1 of EC inhibited CH 4 generation. A higher salt concentration of 80 mS cm À1 of EC inhibited not only CH 4 and CO 2 generation, but also degradation of organic compounds. The bacterial and archaeal community compositions were affected by high salinity. High salinity can exert selective pressure on bacterial communities, resulting in a change in bacterial community structure. Ammonium caused strong, dominant inhibition of biogas production in the salt concentration range of this study. Quality control, especially of ammonium levels, will be essential for the promotion of waste biodegradation in landfills with leachate recirculation.

Abstract
Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an  effective  solution to this problem. The technology that can be used may differ based on the type of  leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The  study  focused on  two  types of leachate:  Palau Borung Landfill leachate with low Coliform content (200 MPN/100  m/L)  and Ampang Jajar landfill leachate with high coliform content (>24 x 104 MPN/100 m/L).  Optimal conditions  for  the  Electro-Fenton  treatment  process  were  applied  on  both  types  of leachate. Then, the coliform was examined before and after treatment using the Most Probable  Number  (MPN)  technique.  Accordingly,  100%  removal  of  coliform  was obtained at low initial  coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate.

Landfill leachate is a highly concentrated organic wastewater with complex compositions. It is a
major source of pollution potentially threatening the quality of groundwater, surface water, and life
forms. The treatment of landfill leachate consists of various combination processes such as biological,
chemical and physical methods. In this study, raw leachate was subjected to an anaerobic treatment
using a modified anaerobic baffled reactor (MABR). Initially, the start-up of the MABR system was
accomplished using meat extract as synthetic feed. The start-up of the reactor was carried out by
maintaining a low chemical oxygen demand (COD) of 350 mg/L at an organic loading rate (OLR) of
0.0875 kg COD/m3/d. Once the reactor attained 99% COD removal, real wastewater (landfill leachate)
was gradually fed into the MABR. The OLR was increased to 0.175, 0.375, 0.75 and 1.40 kg COD/
m3/d, respectively. The process performance of the reactor was evaluated in terms of pH, COD, color,
volatile acid (VA), biogas production and heavy metal removal. Results showed that an average COD
removal efficiency of 79.3% was observed when the OLR was 1.4 kg COD/m3/d. The VA concentration
showed a stable profile with a very little value (38.9 mg/L of HOAc) in the effluent of the reactor for
all the OLR studied. The color removal was 32%, 46%, 45.1% and 78.2% when the OLR was increased
to 0.175, 0.375, 0.75 and 1.40 kg COD/m3/d, respectively. As, Cr and Fe removal was 87.5%, 88.8%,
and 87.8%, respectively, when the reactor was operated at an OLR of 1.4 kg COD/m3/d. The heavy
metals removal

Rapid development of the industrial and domestic sectors has led to the rise of several energy and environmental issues. In accordance with sustainable development and waste minimization issues, biohydrogen production along with biomethane production via two-stage fermentation process using microorganisms from renewable sources has received considerable attention. In the present study, biohythane production with simultaneous wastewater treatment was studied in a two-stage (Biohydrogen and Biomethane) fermentation process under anaerobic conditions. Optimization of high organic content (COD) distillery spent wash effluent (DSPW) with dilution using sewage wastewater was carried out. Addition of leachate as a nutrient source was also studied for effective biohythane production. The experimental results showed that the maximum biohythane production at optimized concentration (substrate concentration of 60 g/L with 30% of leachate as a nutrient source) was 67 mmol/L bio-H2 and with bio-CH4 production of 42 mmol/L.

As a developing country and one of the tropical tourism industry leaders, Malaysia is
faced with environmental problems, such as the conversion of municipal solid waste landfill
leachate into hazardous wastewater in mega cities. High concentrations of pollutants, toxic
refractory component, and complex composition of landfill leachate have serious environmental
impact. This study investigated a novel rapid treatment method to remove turbidity, suspended
solid, color, and ammonia nitrogen. Bentonite augmented sequencing batch reactor with
miscellaneous aeration (0.5–7.5 L/min) and contact time (1–3 h) is applied via response surface
methodology in 13 runs. Results of this study show that in optimum circumstances, 93.63% of
turbidity, 90.42% of total suspended solid, 76.33% of ammonia nitrogen (NH3-N), and 45.96%
color were removed in only three hours. Furthermore, natural bentonite is a cost effective adsorbent
for landfill leachate treatment