A comprehensive study on landfill site selection for Kolkata City,India

Kolkata is one of the four major metropolitan cities in India and the capital city of the state of West Bengal. With an area of 187.33 km² and a population of about 10 million (including a floating population of about 6 million), the city generates about 3500 Metric Ton (MT) of solid waste per day. Currently, Kolkata Municipal Corporation (KMC) disposes its waste at Dhapa (21.47 ha), where the disposal rate exceeds 3000 MT/day, and at Garden Reach (3.52 ha), where the disposal rate is 100 MT/day. Considering the exhaustion of Dhapa land space, city planners are urgently searching for an alternate disposal ground. National Environmental Engineering Research Institute (NEERI), under the sponsorship of Central Pollution Control Board (CPCB), has brought out literature developing the site selection criteria for municipal solid waste disposal ground to suit Indian conditions. The developed criteria encompass environmental conditions, accessibility, geological and hydrogeological conditions, and ecological and societal effects. This paper attempts to locate the most suitable site for disposal of KMC area solid waste using the multicriterion decision analysis as stipulated in CPCB 2003 guidelines and the overlay analysis of geographic information system (GIS).

Implications:The paper is based on landfill site selection for dumping of solid waste generated within Kolkata Municipal Corporation (KMC) area. The methodology uses GIS/remote sensing, Site Sensitivity Index (an offshoot of pairwise comparison technique developed in CPCB 2003 guidelines, Government of India), and the Delphi technique. Dhapa landfill site, where solid waste of KMC area is currently being disposed, is exhausted; the authors of this article thus found it relevant to carry out a research on the selection of an alternative landfill site. The study undertaken was comprehensive, yet presented in a lucid way so that policymakers will find easy to comprehend.     

Metallic and bimetallic phosphides-based nanomaterials for photocatalytic hydrogen production and water detoxification: a review

Environmental Chemistry Letters - Providing sustainable energy and cleaning water pollution are actually major societal issues requiring new catalysts. In particular, transition...     

Performance evaluation of six different aerosol samplers in a particulate matter generation chamber

The present study was carried out with the aim of evaluating the performance of six different aerosol samplers in terms of mass concentration, particle size distribution, and mass fraction for the international size-sampling conventions. The international size-sampling criteria were defined as inhalable, thoracic, and respirable mass fractions with 50% cutoff at an aerodynamic equivalent diameter of 100 μm, 10 μm, and 4 μm, respectively. Two Andersen, four total suspended particulate (TSP), two RespiCon, four PM₁₀, two DustTrak, and two SidePak samplers were selected and tested to quantitatively estimate human exposure in a carefully controlled particulate matter (PM) test chamber. The overall results indicate that (1) Andersen samplers underestimate total suspended PM and overestimate thoracic and respirable PM due to particle bounce and carryover between stages, (2) TSP samplers provide total suspended PM as reference samplers, (3) TSP samplers quantified by a coulter counter multisizer provide no information below an equivalent spherical diameter of 2 μm and therefore underestimate respirable PM, (4) RespiCon samplers are free from particle bounce as inhalable samplers but underestimate total suspended PM, (5) PM₁₀ samplers overestimate thoracic PM, and (6) DustTrak and SidePak samplers provide relative PM concentrations instead of absolute PM concentrations.     

Women drivers' behavior in well-known versus less familiar locations

INTRODUCTION: Through observations this study sought to examine the effects of road familiarity on driving performance. METHOD: Severe and minor traffic violations, dangerous behaviors, and speeding were assessed in well known and in less familiar locations. RESULTS: As compared to less known locations, drivers in well known locations performed more severe and minor violations, more dangerous behaviors, and they drove above the speed limit more often. DISCUSSION: The results are discussed in the context of Theory of Risk Homeostasis (later re-labeled as Target Risk Theory), the psychological effect of familiarity on driving performance, and the phenomenon of automatic driving. Presenting the risk of driving in familiar locations would assist to elevate safe driving.     

Combined sorptional–photocatalytic remediation of dyes by polyaniline Zr(IV) selenotungstophosphate nanocomposite

A polyaniline Zr(IV) selenotungstophosphate nanocomposite was prepared via sol-gel method and characterized by thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The combined sorptional–photocatalytic activity of the nanocomposite for degradation of methylene blue and malachite green was investigated and was found to be more efficient than separate adsorption in the dark followed by photocatalysis. The dyes were degraded in 3 h by 96% and 89% by the combined process, as compared to 86% and 72% by the two-step process in 5 h. The nanocomposite material showed antimicrobial activity against Staphylococcus aureus and Escherichia coli.     

Effects of Instrument Precision and Spatial Variability on the Assessment of the Temporal Variation of Ambient Air Pollution in Atlanta,Georgia

Abstract

Data from the U.S. Environmental Protection Agency Air Quality System, the Southeastern Aerosol Research and Characterization database, and the Assessment of Spatial Aerosol Composition in Atlanta database for 1999 through 2002 have been used to characterize error associated with instrument precision and spatial variability on the assessment of the temporal variation of ambient air pollution in Atlanta, GA. These data are being used in time series epidemiologic studies in which associations of acute respiratory and cardiovascular health outcomes and daily ambient air pollutant levels are assessed. Modified semivariograms are used to quantify the effects of instrument precision and spatial variability on the assessment of daily metrics of ambient gaseous pollutants (SO₂, CO, NO_x, and O₃) and fine particulate matter ([PM_2.5] PM_2.5 mass, sulfate, nitrate, ammonium, elemental carbon [EC], and organic carbon [OC]). Variation because of instrument imprecision represented 7–40% of the temporal variation in the daily pollutant measures and was largest for the PM_2.5 EC and OC. Spatial variability was greatest for primary pollutants (SO₂, CO, NO_x, and EC). Population–weighted variation in daily ambient air pollutant levels because of both instrument imprecision and spatial variability ranged from 20% of the temporal variation for O₃ to 70% of the temporal variation for SO₂ and EC. Wind rose plots, corrected for diurnal and seasonal pattern effects, are used to demonstrate the impacts of local sources on monitoring station data. The results presented are being used to quantify the impacts of instrument precision and spatial variability on the assessment of health effects of ambient air pollution in Atlanta and are relevant to the interpretation of results from time series health studies that use data from fixed monitors.     

Evaluation of Trickle Bed Air Biofilter Performance as a Function of Inlet VOC Concentration and Loading,and Biomass Control

ABSTRACT

The 1990 Amendments to the Clean Air Act have stimulated strong interest in the use of biofiltration for the economical, engineered control of volatile organic compounds (VOCs) in effluent air streams. Trickle bed air biofilters (TBABs) are especially applicable for treating VOCs at high loadings. For long-term, stable operation of highly loaded TBABs, removal of excess accumulated bio-mass is essential. Our previous research demonstrated that suitable biomass control for TBABs was achievable by periodic backwashing of the biofilter medium. Backwashing was performed by fluidizing the pelletized biological attachment medium with warm water to about a 40% bed expansion. This paper presents an evaluation of the impact of backwashing on the performance of four such TBABs highly loaded with toluene. The inlet VOC concentrations studied were 250 and 500 ppmv toluene, and the loadings were 4.1 and 6.2 kg COD/m³ day (55 and 83 g toluene/m³ hr). Loading is defined as kg of chemical oxygen demand per cubic meter of medium per day. Performance deterioration at the higher loading was apparently due to a reduction of the specific surface of the attached biofilm resulting from the accumulation of excess biomass. For a toluene loading of 4.1 kg COD/m³ day, it was demonstrated that the long-term performance of biofilters with either inlet concentration could be maintained at over 99.9% VOC removal by employing a backwashing strategy consisting of a frequency of every other day and a duration of 1 hr.     

Ambient air quality during wheat and rice crop stubble burning episodes in Patiala

Open crop stubble burning events were observed in and around Patiala city, India. A ground level study was deliberated to analyze the contribution of wheat (Triticum aestivum) and rice (Oriza sativa) crop stubble burning practices on concentration levels of aerosol, SO₂ and NO₂ in ambient air at five different sites in and around Patiala city covering agricultural, commercial and residential areas. Aerosols were collected on GMF/A and QMF/A (Whatman) sheets for a 24 h period throughout the year in 2007. Simultaneously, sampling of SO₂ and NO₂ was conducted and results obtained during stubble burning periods were compared to the non-stubble burning periods. Results clearly pointed out a distinct increase in aerosol, SO₂ and NO₂ levels during the crop stubble burning periods.     

Development,Malaria and Adaptation to Climate Change: A Case Study from India

India has reasons to be concerned about climate change. Over 650 million people depend on climate-sensitive sectors, such as rain-fed agriculture and forestry, for livelihood and over 973 million people are exposed to vector borne malarial parasites. Projection of climatic factors indicates a wider exposure to malaria for the Indian population in the future. If precautionary measures are not taken and development processes are not managed properly some developmental activities, such as hydro-electric dams and irrigation canal systems, may also exacerbate breeding grounds for malaria. This article integrates climate change and developmental variables in articulating a framework for integrated impact assessment and adaptation responses, with malaria incidence in India as a case study. The climate change variables include temperature, rainfall, humidity, extreme events, and other secondary variables. Development variables are income levels, institutional mechanisms to implement preventive measures, infrastructure development that could promote malarial breeding grounds, and other policies. The case study indicates that sustainable development variables may sometimes reduce the adverse impacts on the system due to climate change alone, while it may sometimes also exacerbate these impacts if the development variables are not managed well and therefore they produce a negative impact on the system. The study concludes that well crafted and well managed developmental policies could result in enhanced resilience of communities and systems, and lower health impacts due to climate change.