Degradations of endocrine-disrupting chemicals and pharmaceutical compounds in wastewater with carbon-based nanomaterials: a critical review

Environmental Science and Pollution Research - Although water occupies 75% of the earth’s surface, only 0.0067% of the total water is available for human activities. These statistics further...     

Alternative Control Policies for Water Quality Management: An Experimental Economics Approach

Problems of deteriorating water quality and the prospects of large invest ments for treatment facilities have motivated government decision makers to seek more cost-effective means to manage water quality. The most preferred policy advocated by economists is based on economic incentives. But the response of water quality managers to a particular incentive system cannot be predicted a priori . Before any incentive system is implemented, its effectiveness must be evaluated. Mathematical programming models have been used for this purpose. Experimental economics provides an alternative mechanism for testing the effectiveness of such a system. It can also help identify the necessary parameters of incentive-based systems. The objective of this paper is to describe the results of an experiment for evaluating the effectiveness of managing water quality under two different policies: a command and control policy; and a transferable discharge permit (TDP) policy. A review of previous research on the effectiveness of TDP systems is provided along with arguments supporting the use of experimental economics to investigate these problems. The particular experiments developed for this research along with the experimental procedures are described. Key results and observations from the experiments are presented.     

Investigations of ash topography/morphology and their relationship with heavy metals leachability

The leachability of heavy metals such as chromium (Cr), lead (Pb) and cadmium (Cd) from the ash material obtained from waste combustion was studied. The effects of ash surface topography and morphology on the leachability of these elements were examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The AFM (scan size 10 x 10 microns) and SEM images of the simulated ash pellet obtained at various operating temperatures (1000, 1400 and 1500 degrees C) showed significant microstructural and topographical changes. Ash pellets treated at 1000 degrees C contain porous and non-continuous surface. On the other hand, the ash pellet obtained at higher temperature (1500 degrees C) was found to contain a smooth, continuous and non-porous surface. The AFM height profile studies indicated that the top surface variation of the ash pellet at 1000, 1400 and 1500 degrees C were found to be -40.0 to 25.5, -3.7 to 4.7 and -0.10 to 0.66 nm respectively. The SEM analyses also confirmed the presence of smooth, non-porous outer surface of ash formed at 1500 degrees C. In addition, it also showed the presence of compact and rigid interior for the same ash pellet. The leachability of the heavy metals was determined using standard toxicity characteristic leaching procedure (TCLP) test and the samples were analysed using atomic absorption spectroscopy. The results showed that the TCLP leaching ratios of the heavy metals were Cr = 0.30, Pb = 0.05 and Cd = 0.09 at 1000 degrees C. However, the ash obtained at 1400 degrees C showed negligible heavy metals leaching ratio while at 1500 degrees C no leachability was detected (TCLP concentration dropped to nondetectable levels). The use of high temperature treatment enabled the immobilization of heavy metals in the ash preventing their leaching. Such ash can be considered as a non-hazardous material for reuse or safe disposal.     

Snow cover and vegetation greenness with leaf water content control the global land surface temperature

The land surface temperature (LST) and land use land cover (LULC) are the major components of climate- and environment-related studies. The objective of this study was to assess the relationship of LST with remotely sensed LULC-derived vegetation indices during 2018 at the global, latitudinal and continental scales. Moderate resolution imaging spectroradiometer (MODIS) Aqua daytime LST and eight LULC MODIS indices (NDVI, EVI, LAI, DSI, NDWI, albedo, NDSI, NDBI) were processed using Earth Engine Code Editor. The analysis was conducted using correlation coefficient and significance of the relationship of variables based on 2050 randomly selected points at the global scale. Based on the univariate and geographically weighted regression methods, the research confirmed that vegetation greenness (NDVI), leaf water content (NDWI) and snow cover (DSI) are the codominant drivers of decreasing LST at the global scale including Europe, Asia, South America and North America at the continental scale. Snow cover during winter and vegetation greenness in summer seasons control the global LST. Although albedo shows an inverse relationship, NDBI and NDSI displayed a positive relationship to LST at the global scale. In conclusion, temporal seasonal and inter-annual dynamics of LST in response to snow cover and vegetation properties (greenness, moisture) should be focused on understanding and regulating LST at varying scales.

     

Degradation of dyes from aqueous solution by Fenton processes: a review

Several industries are using dyes as coloring agents. The effluents from these industries are increasingly becoming an environmental problem. The removal of dyes from aqueous solution has a great potential in the field of environmental engineering. This paper reviews the classification, characteristics, and problems of dyes in detail. Advantages and disadvantages of different methods used for dye removal are also analyzed. Among these methods, Fenton process-based advanced oxidation processes are an emerging prospect in the field of dye removal. Fenton processes have been classified and represented as “Fenton circle”. This paper analyzes the recent studies on Fenton processes. The studies include analyzing different configurations of reactors used for dye removal, its efficiency, and the effects of various operating parameters such as pH, catalyst concentration, H₂O₂ concentration, initial dye concentration, and temperature of Fenton processes. From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.     

Remanufacturing for the automotive aftermarket-strategic factors: literature review and future research needs

While the concepts of remanufacturing and reverse logistics are gaining popularity in practice, the available literature and theory on strategic decision making in these areas are limited. This paper is designed to address this gap, in particular, for the automotive industry aftermarket. In doing so, the authors reviewed literature pertaining to: customer demand(s), product design and development, cost-benefit analysis of reman, core (i.e., used product) supply management, reman competencies and skills, product life cycle strategies, reman and reverse logistics network design, relationships among key stakeholders, environmental considerations, regulations, and impact of emerging economies. The literature findings along with our experience in working with automotive reman products were used as inputs to guide the formulation of seven major propositions for the strategic factors in decision making within reman. The propositions were then tested through a case study. The case study reconfirmed many of the factors like product life cycle, regulations, etc. from the literature review and also identified new factors like OE customer requirements. Our results provide a foundation for further research for companies that deal with Original Equipment (OE) Sales, Original Equipment Service (OES), as well as Independent Aftermarket (IAM) business in the automotive industry.     

Biosynthesis and effects of copper nanoparticles on plants

Copper nanoparticles have improved properties compared to the bulk copper material. Copper nanoparticles indeed find applications in gas sensors, heat transfer fluids, catalysis, solar energy and batteries. Antibacterial and antifungal activities of copper nanoparticles find applications in the agriculture and healthcare sectors. Nonetheless, careless use of copper nanoparticles may cause environmental pollution and health effects. Here we review the biosynthesis of copper nanoparticles using plant materials, named phytosynthesis, and micro-organisms. We also discuss the effect of copper nanoparticles on crops and pathogenic micro-organisms. Copper nanoparticles varying in sizes from 5 to 295 nm have been synthesized using leaf extracts and latex from plants, and using bacteria and fungi. Biosynthesized copper nanoparticles show good antimicrobial activity inhibiting the growth of pathogenic bacteria and pathogenic fungi. Copper nanoparticles enhance the germination and growth of some plants at lower concentrations, whereas high concentrations result in retarded growth.     

Natural and Anthropogenic Effects On Phytoplankton Primary Productivity in Mangroves

Spatial and temporal variations and the factors influencing primary production have been studied in three different mangrove waters (Pichavaram, Ennore Creek and Adyar Estuary) of South India characterised by different anthropogenic impacts. the gross primary productivity in the unpolluted Pichavaram mangrove was 113 g Cm^-2yr^-1 exhibiting natural variability with the environmental forcing factors. Human activities have elevated primary productivity in the Ennore Creek mangrove (157g Cm^-2yr^-1) primarily through the direct discharge of fertilizer effluents. By contrast, a combination of domestic and industrial effluent discharges into the Adyar Estuary mangrove has considerably reduced phytoplankton primary productivity 83g Cm^-2yr^-1 the Redfield N: P ratio varies from 0.96 N: 1P at Ennore Creek, 1.75N: 1P at Adyar Estuary to 15.2 N: 1P at Pichavaram mangroves. This suggests that the Pichavaram mangroves represent a well equilibrated ecosystem with N: P ratio close to steady-state values in contrast to the anthropogenically altered mangrove ecosystems studied. Results show a significant temporal variability in nutrient concentration in the three mangrove areas. Distinct differences in nutrient concentrations between the dry and the wet seasons have been observed.     

Fluoride sorption by treated fly ash: kinetic and isotherm studies

High fluoride levels in drinking water have become a critical health hazard. In the present study, the performance of magnesia-loaded fly ash adsorption in the removal of fluoride from aqueous solution was investigated in a batch study. The effect of contact time, dosage, pH, temperature and agitation speed was studied at different values. The maximum removal efficiency was 88 % at 150 min. The effective dose of adsorbent was found to be 2.5 g/l. The optimum pH was found to be at pH 4. Kinetic studies and isotherm studies were also performed to understand the ability of the adsorbents. The monolayer adsorption capacity determined from the Langmuir adsorption equation was found to be 11.61 mg/g. The kinetic measurements suggested the involvement of pseudo-second-order kinetics in adsorption and were controlled by a particle diffusion process. Overall, the results of this study suggest that magnesia-loaded fly ash is an environmentally friendly, efficient and low-cost adsorbent, useful for the removal of fluoride from aqueous solution.