Journal of environmental science & engineering

Abstract:Batch adsorption studies were undertaken to assess the suitability of commercially available activated charcoal to remediate fluoride-contaminated water The effects of some of the major parameters of adsorption, viz pH, dose of adsorbent, rate of stirring, contact time and initial adsorbate concentration on fluoride removal efficiency were studied and optimized The optimum sorbent dose was found to be 20 g/100 mL, equilibrium was achieved in 120 minutes and enhanced adsorption was obtained at pH 2 Maximum fluoride removal was observed to be 94% at optimum conditions Freudlich as well as Langmuir isotherms were plotted and kinetic constants were determined

Abstract:Several strategic metals, elements and energy resources are about to run into scarcity in the near future under the present paradigm of use. A global systems model has been developed (WORLD) to assess the issue of scarcity and its implications for society. We show that scarcity may lead to “peak wealth”, “peak population”, “peak waste” and “peak civilization”, unless urgent counter-measures are systematically undertaken. Materials that underpin modern society may become unavailable for global mass production of goods. The material volumes that can be supplied from fossil reserves will be reduced with respect to today and resources will go up in price. The future resource supply is unsustainable without comprehensive recycling. The creation of wealth from conversion of resources and work, as well as the current extensive borrowing from the future, cause concerns that peaking energy and materials production may lead to “peak wealth” and the end of the golden age we live in. Our policy recommendations are that governments must take this issue seriously and must immediately start preparing legislations to close material cycles, optimize energy use and minimize irreversible material losses. Research efforts need to be based on systems thinking and a concerted effort is needed. (Less)

Abstract:Fluoride concentrations in surface and ground water samples were determined in eight villages of Prakasham district in India. Thirty-eight samples were collected and analysed for fluoride content along with pH, electrical conductivity, total dissolved solids (TDS), total hardness, total alkalinity, chlorides (C1), sulfates (SO2-) and nitrates (NO ). Fluoride concentrations in surface and ground water samples of these villages varied between 0.5 and 9.0 mg/L. Groundwater samples contained high concentrations of fluorides compared to open well and pond water samples, which could be a major source of fluoride in water since the geological formation of this area consists of fluorite and fluoropatite. From the data, it is evident that the population in the study area is severely affected by fluorosis. Dental and skeletal fluorosis and deformation of bones in children as well as adults were observed in the study area indicating the consequences of excess fluoride concentration. Fluoride concentrations showed good correlation with TDS concentrations (R2 of 0.61) compared to other physico-chemical parameters [EC (R2 - 0.36), nitrate (R - 0.24), total hardness (R - 0.12), chloride (R2 - 0.06) and sulfate (R2 - 4 x 10(-6))].

Abstract:� Abstract—The potential of economically cheaper cellulose containing natural materials like rice husk was assessed for nickel adsorption from aqueous solutions. The effects of pH, contact time, sorbent dose, initial metal ion concentration and temperature on the uptake of nickel were studied in batch process. The removal of nickel was dependent on the physico-chemical characteristics of the adsorbent, adsorbate concentration and other studied process parameters. The sorption data has been correlated with Langmuir, Freundlich and Dubinin-Radush kevich (D-R) adsorption models. It was found that Freundlich and Langmuir isotherms fitted well to the data. Maximum nickel removal was observed at pH 6.0. The efficiency of rice husk for nickel removal was 51.8% for dilute solutions at 20 g L -1 adsorbent dose. FTIR, SEM and EDAX were recorded before and after adsorption to explore the number and position of the functional groups available for nickel binding on to the studied adsorbent and changes in surface morphology and elemental constitution of the adsorbent. Pseudo-second order model explains the nickel kinetics more effectively. Reusability of the adsorbent was examined by desorption in which HCl eluted 78.93% nickel. The results revealed that nickel is considerably adsorbed on rice husk and it could be and economic method for the removal of nickel from aqueous solutions.

Abstract:固体废物管理(SWM)是一种最不glected aspects of India's environment and the recent Municipal Solid Waste (Management and Handling) Rules 2000 have made it mandatory for the administrative authority of any area to undertake responsibility for all activities relating to municipal solid waste management (MSWM). A survey of MSWM practices in Indian urban local bodies (ULBs) and the literature suggest that major problems in MSWM in India are: underestimation of generation rates and therefore, underestimation of resource requirements, lack of technical and managerial inputs, and lack of reliable and updated information to the public and practitioners in the field. India is a developing country whose economy is currently growing at an extremely rapid annual growth rate of 8 to 9%. Based on trends in countries like the US, and China, and European countries, it is clear that a growing economy and population are likely to result in growth rates of 11 to 12% in MSW generation. These growth rates are much higher than the current expert estimates of 1.3 % for per capita MSW generation and 4.2% for total MSW generation. The present ad hoc approach to MSW collection and transport results in inefficient utilization of resources. Modern technology and tools like remote sensing, GIS and mathematical optimatization methods can be used for more efficient allocation and utilization of resources.