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Item 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.Item 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.Item Interactions Between Soils and Laboratory Simulated Electrolyte Solution(2010) Nayak, S.; Sunil, B.M.; Shrihari, S.; Sivapullaiah, P.V.To study the impact of salt water intrusion on two types of soils from west coast region of India were investigated in the laboratory. The key characteristics evaluated included Atterberg limits, compaction characteristics, hydraulic conductivity and chemical characteristics of selected soils. The sea at this coast receives effluent from different points and hence the characteristics change with time and locality. Therefore, to maintain uniform composition, 0.5 N sodium chloride solution (NaCl) was prepared in the laboratory and batch tests were used to determine the immediate effect on soils. Soil specimens were prepared by mixing the soils with 0.5 N NaCl in the increments of 0, 5, 10 and 20% by weight to vary the degree of contamination. Experimental results of soils mixed with 0.5 N NaCl showed that the maximum dry density increases and the optimum moisture content (OMC) decreases with increasing sodium chloride concentration. The study also revealed that the hydraulic conductivity of the soils tested increases with increase in sodium chloride concentration. The Atterberg limits of contaminated specimens show a remarkable change when compared with uncontaminated specimens. 2010 Springer Science+Business Media B.V.Item Evaluation of water quality index for drinking purposes for river Netravathi, Mangalore, South India(2008) Avvannavar, S.M.; Shrihari, S.An attempt has been made to develop water quality index (WQI), using six water quality parameters Dissolved oxygen (DO), Biochemical oxygen Demand (BOD), Most Probable Number (MPN), Turbidity, Total Dissolved Solids (TDS) and pH measured at eight different stations along the river basin. Rating curves were drawn based on the tolerance limits of inland waters and health point of view. Bhargava WQI method and Harmonic Mean WQI method were used to find overall WQI along the stretch of the river basin. Five point rating scale was used to classify water quality in each of the study areas. It was found that the water quality of Netravathi varied from Excellent to Marginal range by Bhargava WQI method and Excellent to Poor range by Harmonic Mean WQI method. It was observed that the impact of human activity was severe on most of the parameters. The MPN values exceeded the tolerable limits at almost all the stations. It was observed that the main cause of deterioration in water quality was due to the lack of proper sanitation, unprotected river sites and high anthropogenic activities. Springer Science+Business Media B.V. 2007.Item Evaluation of pyrolyzed areca husk as a potential adsorbent for the removal of Fe2+ ions from aqueous solutions(2019) Sheeka, Subramani, B.; Shrihari, S.; Manu, B.; Babunarayan, K.S.The hurdle of valorisation of Arecanut husk on one side and the pollution of aquatic bodies by heavy metals like Iron on the other end are contemplated together in this study. The areca husk is pyrolyzed at 450°C for two hours to obtain Biochar. Batch adsorption studies were employed to investigate the effect of adsorbent dosage (2-10 g/l), initial concentration of adsorbate (1-5 mg/l) and contact time (30 -360 min) at temperature of 28±2 °C & pH4.0±0.2 on the removal of Iron from pyrolyzed areca husk. The adsorption capacity was found to increase with increase in initial Iron concentartion and contact time, but decreases with the adsorbent dosage. Langmuir, Freundlich, Temkin and Dubinin-Radushkevich Isotherms was used to analyse the equilibrium data. Langmuir and Dubinin-Radushkevich model best describe the uptake of Iron ions implying a monolayer adsorption with physisorption. Pseudo second order, exhibited the best fit for the effectiveness of Iron adsorbtion indicating the maximum limit of chemisorption. Thermodynamic studies indicated that the adsorption was spontaneous and exothermic in nature. The mechanisms responsible for adsorption of Iron on pyrolysed areca husk was conducted by SEM-EDAX, XRD and FTIR indicating oxidation and precipitaion of Iron into complex compounds of jarosite and ferrous hydroxy sulphates. In conclusion, pyrolyzed areca husk can be technically & economically feasible alternative adsorbent material.Item Effect of pH on the geotechnical properties of laterite(2006) Sunil, B.M.; Nayak, S.; Shrihari, S.Environmental Geotechnology has emerged as an interdisciplinary science, aiming and forecasting, analyzing and solving the geotechnical problems involving the influence of environmental factors. Lateritic soil of west coast region of India was studied to investigate the effect of soaking on the engineering properties and chemical characteristics of soil, soaked in different pH solutions (pH = 5.0, pH = 7.0, pH = 8.0). 12 N hydrochloric acid and 15 M ammonia solution were used to monitor the pH of the solution for about ninety days. Results showed that the pH of the solution has strong influence on the chemical characteristics of lateritic soil. The engineering properties of soil are altered when compared with the initial characteristics of the soil. The reason for this observed behavior of the soil is addressed in this paper. 2006 Elsevier B.V. All rights reserved.Item Determination of water quality deterioration at pilgrimage centre along river Netravathi, Mangalore using WQI Approach(2007) Avvannavar, S.M.; Shrihari, S.An attempt has been made to develop Water Quality Index (WQI), using six water quality parameters at riverside stations located in the vicinity of temples of Dakshina Kannada district, Karnataka, South India. Rating curves were drawn based on the tolerance limits of inland waters and health point of view. Bhargava WQI method and Harmonic Mean WQI method were used to find overall WQI along the stretch of the river basin. Five point rating scale was used to classify water quality in each of the study areas. It was found that the water quality of Netravathi varied from Excellent to Marginal range by Bhargava WQI method and Excellent to Poor range by Harmonic Mean WQI method. It was observed that the impact of human activity was severe on most of the parameters. The MPN values exceeded the tolerable limits at almost all the stations. It was observed that the main cause of deterioration in water quality was due to the lack of proper sanitation, unprotected river sites and high anthropogenic activities. 2007, Gheorghe Asachi Technical University of Iasi, Romania. All rights reserved.Item Soil-leachate interaction and their effects on hydraulic conductivity and compaction characteristics(2008) Sunil, B.M.; Shrihari, S.; Nayak, S.Leachate is the most dangerous component of the solid waste management process. In a small landfill, the amount of leachate generated may not create a serious problem. As the size of landfill and variety of solid wastes disposed increases, large amounts of leachate will be generated and create environmental problems such as leaching of nutrients and heavy metals into the soil which leads to soil and ground water contamination. The problem of change in behaviour of soils on one hand and the contamination of ground water on the other is a cause of concern for geotechnical and environmental engineers. In this paper, results of a laboratory study to determine the effects of leachate contamination on the hydraulic conductivity and compaction characteristics of shedi soil (also known as lithomargic clay) have been presented. The study has indicated that leachate can modify the soil properties and significantly alter the behaviour of soil. There is a general deterioration in soil properties which is attributed to the chemistry of leachate and of soil. The interaction of leachate with soil is responsible for the modified behaviour of the soil.