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    Characterization of the MSW leachate at Mangalore dump yard, India
    (2006) Ravishankar, R.; Madhuri, B.; Mugeraya, G.
    In India, solid waste generation is about 1,00,000 MT per day, of which over 90% is land filled. Landfills are nothing but dump yards without top and bottom impermeable layers. All types of wastes viz., Hazardous, Industrial and even biomedical waste are dumped in these yards. Municipal agencies, responsible for handling wastes, are constructing engineered land fills wherever additional land is available as per MSW (Handling & Management) Rules 2000. The rule stipulates the same limits for leachate discharge as that of industrial wastes. But the characteristics of leachate are not available with the authorities to decide on the system of treatment process. As new landfills are being constructed it is very essential to have a data on the MSW leachate characteristics for deciding on the best treatment method. Therefore in this study the characteristics of the leachate generating from Mangalore MSW landfill was studied during July 2004 to November 2004. pH of the leachate is on the basic side with the value around 8.1±0.2. There is no much variation in the temperature as it was 27°C during July'04 and increased only by 2°C to 29.2°C. towards the end of the study period. Total solids initially decreased from 12800 mg/L to 10300 mg/L due to post monsoon season and as the rainwater dilution decreases, the value of solids increased to 14530 ppm. Total dissolved solids gradually increased from 6700ppm to 10,530 ppm, which is very high compared to standards (2100 ppm). BOD and COD values gradually increased from 200 to 1200 ppm and 2000 to 7200 ppm respectively. This gradual increase can be attributed to the decreased amount of infiltration. These values are much higher than the stipulated standards. Copyright © Enviromedia.
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    Hydraulic and compaction characteristics of leachate-contaminated lateritic soil
    (2007) Nayak, S.; Sunil, B.M.; Shrihari, S.
    Large quantities of leachate-contaminated lateritic soil results from dump yards in the southwest coast of India. These dump yards receive large quantities of municipal solid waste which includes chemical, industrial and biomedical wastes. Large areas of land are currently being used for this purpose. An extensive laboratory testing program was carried out to determine the compaction characteristics and hydraulic conductivity of clean and contaminated lateritic soil. Batch tests were used to study the immediate effect of leachate contamination on the properties of lateritic soil. Contaminated specimens were prepared by mixing the lateritic soil with leachate in the amount of 5%, 10% and 20% by weight to vary the degree of contamination. The results indicated a small reduction in maximum dry density and an increase in hydraulic conductivity due to leachate-contamination. The change induced by chemical reaction in the microstructure of the soil was studied by scanning electron microscope before and after contamination of soil with leachate. The structure of the leachate contaminated soil sample appeared to be aggregated in scanning electron microscope analysis. The aggregated structure increases the effective pore space and thus increases the hydraulic conductivity. Fifty percent increase in hydraulic conductivity was observed for specimens prepared at standard Proctor density and mixed with 20% leachate. Compaction characteristics did not change much with the presence of leachate up to 10%. With 20% leachate the maximum dry density decreased slightly indicating excess leachate in the soil. However the changes are not significant. © 2007 Elsevier B.V. All rights reserved.
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    Shear strength characteristics and chemical characteristics of leachate-contaminated lateritic soil
    (2009) Sunil, B.M.; Shrihari, S.; Nayak, S.
    Leachate is a hazardous liquid and is a major cause of concern in landfills. Numerous environmental problems such as soil and groundwater contamination occur in unlined landfills due to free flow of leachate. Large quantities of leachate-contaminated soils result from open dumping in the study area. These dump yards receive large quantities of municipal solid waste which includes chemical and industrial wastes. Large areas of land are currently being used for this purpose. An extensive laboratory testing program was carried out to determine the properties of clean and contaminated lateritic soils. Laboratory prepared municipal solid waste leachate was used in this study. Contaminated specimens were prepared by mixing the soils with MSW leachate in the increments of 0%, 5%, 10% and 20% by weight to vary the degree of contamination. The results showed that the MSW leachate affects the Atterberg limits, shear strength and chemical characteristics of the lateritic soils. The liquid limit and the plasticity index of the lateritic soils increases with MSW leachate concentration. For specimens tested at the Proctor density, effective cohesion increases and effective friction angle decreases due to increase in leachate concentration. This is attributed due to the increase in clay content of lateritic soil after interaction with the leachate. This led to increase in cohesion parameter and the friction angle decreases. The pH measurements of lateritic soil contaminated with MSW leachate indicated an increase in pH values. This is also accompanied by slight increase in the cation exchange capacity of the soil. The change in chemical characteristics of lateritic soil contributed due to addition of leachate may be detrimental to foundation concrete in real field conditions. The present work deals with an attempt to study the effect of leachate on the Atterberg limits, shear strength properties and chemical characteristics of lateritic soil. © 2009 Elsevier B.V. All rights reserved.
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    Predictive simulation of leachate transport in a coastal lateritic aquifer when remediated with reactive barrier of nano iron
    (Elsevier B.V., 2020) Divya, A.; Shrihari, S.; Ramesh, H.
    The current study focuses on determination of extent of groundwater contamination on a typical tropical coastal aquifer due to a landfill located at Vamnjoor in Dakshina Kannada district, India with the help of groundwater flow model, MODFLOW and MT3DMS when remediated with permanent reactive barrier of nano iron. The aquifer considered is a shallow, unconfined one with laterite soil which gets good rains during monsoon and will be dry during rest of the year. The adsorption by laterite soil has been considered. The specific yield and transmissivity were estimated to be 7.85% and 213m2/day respectively. After calibrating successfully with Nash–Sutcliffe efficiency 0.8, horizontal hydraulic conductivity was set as 7 m/day. Validation of model was then done with the field data and is applied for forecasting the spread of contaminant for anticipated future scenarios. The results show that in spite of retardation offered by lateritic soil, contaminant trail is expanding with a velocity of 0.15 m/day in downstream direction. When permeable reactive barrier of nano iron which can adsorb nearly 65% of chemical oxygen demand is installed, it is showing that the contaminant spread can be reduced to 400 mg/l at the observation well located at 1 km from landfill. Hence a comprehensive remedial alternative of permanent reactive barrier of nano iron can be recommended for preventing groundwater contamination from landfill leachate. © 2020 Elsevier B.V.
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    Assessment of Environmental Impact of Aquaculture Ponds in the Western Delta Region of Andhra Pradesh
    (MDPI, 2022) Thotakura, T.V.; Malegole, S.B.; Chaudhary, B.; Gobinath, G.
    Aquaculture is persistent and well-established in the delta region of Andhra Pradesh. In recent years, the expansion of aquaculture has conferred positive economic growth in the newly formed state. However, the enormous development of aqua ponds increases the effluents from aquaculture which contain various chemical compounds that can cause negative impacts when released into the environment. This paper presents the effect of unengineered aquaculture on the environment in the delta region of Andhra Pradesh. The expansion rate of aquaculture practice in the delta region has been carried out using remote sensing and a geospatial information system. An experimental investigation was carried out on soil and water samples collected from the aquaculture ponds to evaluate the water quality parameters and soil characterization. Analysis of the geotechnical properties and microstructure was carried out to determine the interaction between the soil and the aquaculture contaminants. Based on the geospatial data and field survey, the aquaculture practice in the delta region of Andhra Pradesh was intensive and extended towards the northeast from the southwest. Between 2016 and 2020, aquaculture practice significantly increased by 6.08%. Moreover, the water quality parameters and pond bottom soil showed a higher concentration of ammonia and nitrates. Further, aquaculture leachate may interact with the subsoil and have a negative impact on soil mineralogy and hydraulic conductivity. The extensive experimental data and field surveys reveal that adequate guidelines are needed to control the pollution load on the ecosystem. © 2022 by the authors.
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    An approach to quantify the contamination potential of hazardous waste landfill leachate using the leachate pollution index
    (Institute for Ionics, 2024) Ambujan, A.; Thalla, A.K.
    A significant portion of the hazardous wastes generated by rapid industrialisation and urbanisation end up in landfills. The wastes disposed of in hazardous waste landfills are less biodegradable; thus, the leachate generated due to the physical and chemical changes in the landfill renders high toxicity. If not monitored and handled appropriately, this leachate could lead to contamination affecting human and livestock health and adversely affect the soil and agriculture in the vicinity of the landfill site. A tool to quantify the contamination caused by improper handling of hazardous waste landfill leachate is essential to understand which landfill site would need immediate attention. In the present study, the leachate pollution index is developed based on the predominantly available pollutants in hazardous waste landfill leachate and their toxicity limits. Fuzzy Delphi-Analytic Hierarchy Process has been used to develop the index. These techniques have been used for screening and assigning weights to the pollutants. Further, sub-index curves have been developed considering the available concentration, the toxicity, and the standard concentration limits for each pollutant. The weighted linear sum function has been used to aggregate the weights and sub-index scores. The hazardous waste landfill leachate pollution index developed in this study can serve as a potential tool for quantifying the leachate contamination potential. Furthermore, it can be used as a comparison tool for ranking landfill sites based on the contamination potential. © 2023, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.
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    Adsorption – Advanced oxidation process (AAOP) for the heavy metals and organic matter removal from leachate using combined filtration -Fenton's and Photo-Fenton's treatment
    (Academic Press, 2024) Bhaskar, B.; Shree K N, R.; Apoorva, A.; Marikunte Yanjarappa, S.
    Design of cost – effective filtration unit was carried out to evaluate the efficiency of different filter media made of locally available materials to treat raw leachate. Four different filter media laterites, peat, bagasse and a mixture of all were considered as study filter media for the removal of Zinc, Nickel, Copper and Lead from raw leachate. The reactor exhibited a significant removal efficiency when the three-filter media were combined as a combination. A removal rate of around 83.0% and 64.12% was found for nickel and copper, respectively, with a combined filter medium. The order of heavy metal removal varied depending on the kind of filter media used. For combined filter media, the sequence was Ni > Cu > Pb > Zn. For bagasse filter media, it was Pb > Cu > Zn > Ni. For peat filter media, it was Ni > Cu > Pb > Zn. For laterite filter media, it was Zn > Cu > Ni > Pb. Insignificant removal of heavy metals was observed with bagasse in the current investigation and hence is not recommended for use as a filter medium. Pre-treated leachate was subjected to Fenton's oxidation and UV-Fenton's oxidation for organic matter removal. Green synthesized bleached laterite iron nanoparticles were used as a catalyst in the Fenton treatment. COD removal of 80.0% and 85.0% was observed with 0.5 g/L of nano iron catalyst and 500 mg/L of H2O2 and 100 mg/L of H2O2 on Fenton's oxidation and UV-Fenton's oxidation respectively. The synthesized particles were demonstrated to possess a catalytic function in the reduction of COD. Both Fenton's oxidation and UV-Fenton's oxidation exhibit pseudo-first-order kinetics with linear regression. © 2024 Elsevier Ltd
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    A comprehensive study on quantification and characterization of microplastics in compost, landfill-soil and leachate
    (SAGE Publications Ltd, 2025) Dubey, A.P.; Thalla, A.K.
    Microplastics (MPs), a category of synthetic emerging pollutants, have been detected in various environmental matrices. This study assesses the abundance of MPs in the soil, wet compost (WC), Black soldier compost (BSC) and landfill leachate (LL) of the municipal solid waste management plant. Samples were pretreated with a Fenton reagent, followed by density separation and analysed using a digital portable microscope. They were then categorized based on their shape, colour and size to provide information on their distribution. The work reveals an average MP count of 7590?±?1004.092 MP kg?1in soil. MPs were 5900?±?565.69 MP kg?1for BSC, 11,350?±?353.55 MP kg?1for WC and LL samples 98.83?±?6.83 MP L?1. Notably, a significant proportion of MPs, 85% in soil, 86% in compost and 72.6% in LL, measured size less than 300?µm. Samples showed different proportions of fragments, microbeads and fibres, with white/transparent and black being the predominant colours of MPs. Additionally, the study identifies the physicochemical properties of the samples, and the polymer types are identified using attenuated total reflectance-Fourier transform infrared spectroscopy. The study revealed that polypropylene and polyethylene are the most abundant polymers in the samples, indicating that landfills serve as significant sources of MPs. The adopted MP extraction method was tested for its recovery efficiency, and the recovery rates for leachate, compost and soil were found to be 94.3%, 80% and 77.9%, respectively. This research offers insight into the types and abundance of MPs in southern India’s landfills, prompting further studies on detection methods. © The Author(s) 2025