Regulatory attitudes and environmental innovation in a model combining internal and external R&D

The extent to which environmental regulatory institutions are either ‘green’ or ‘brown’ impacts not just the intensity of regulation at any moment, but also the incentives for the development of new pollution-control technologies. We set up a strategic model of R&D in which a polluter can deploy technologies developed in-house, or license technologies developed by specialist outsiders (an ‘eco-industry’). Polluters exert R&D effort and may even develop redundant technologies to improve the terms on which they procure technology from outside. We find that, while regulatory bias has an ambiguous impact on the best-available technology, strategic delegation to systematically biased regulators can improve social welfare.     

Mapping the organic carbon stocks of surface soils using local spatial interpolator

The largest uncertainties are associated with estimating the soil organic carbon (SOC) stock because of natural soil variability and data scarcity. Thus, a local spatial geostatistical hybrid approach, the geographically weighted regression kriging (GWRK), was used in the present study to overcome some of these uncertainties. This study was designed to estimate the SOC stock (kg C m(-2)) for the surface 0 to 15 cm depth using the state of Pennsylvania as the study region. A total of 920 soil profiles were extracted from the National Soil Survey Center database and were divided into calibration (80%) and validation (20%) periods. Some soil parameters that include clay content, bulk density (ρ(b)), total nitrogen (TN) content, pH, Ca(2+), Na(+), extractable acidity (EXACID), and cation exchange capacity (CEC) were used as covariates for estimating the SOC stock. These covariates exhibited spatial autocorrelation (Moran's Index, I = 0.62 to 0.89). Further, residuals of geographically weighted regression were spatially autocorrelated, and hence support the use of the GWRK approach. Validation results concluded that the performance of the GWRK approach was the best with the lowest values of root mean square error, mean estimation error and mean absolute estimation error. The estimated SOC stock for the surface 0 to 15 cm depth ranged from 1.41 to 3.94 kg m(-2). Results from this study show that the GWRK captures spatial dependent relationships, and addresses spatial non-stationarity issues, hence this approach improves the estimations of SOC stock.     

Nanomaterials photocatalytic activities for waste water treatment: a review

Water is necessary for the survival of life on Earth. A wide range of pollutants has contaminated water resources in the last few decades. The presence of contaminants incredibly different dyes in waste, potable, and surface water is hazardous to environmental and human health. Different types of dyes are the principal contaminants in water that need sudden attention because of their widespread domestic and industrial use. The toxic effects of these dyes and their ability to resist traditional water treatment procedures have inspired the researcher to develop an eco-friendly method that could effectively and efficiently degrade these toxic contaminants. Here, in this review, we explored the effective and economical methods of metal-based nanomaterials photocatalytic degradation for successfully removing dyes from wastewater. This study provides a tool for protecting the environment and human health. In addition, the insights into the transformation of solar energy for photocatalytic reduction of toxic metal ions and photocatalytic degradation of dyes contaminated wastewater will open a gate for water treatment research. The mechanism of photocatalytic degradation and the parameters that affect the photocatalytic activities of various photocatalysts have also been reported.

     

Case Studies on Biological Treatment of Tannery Effluents in India

Abstract

This paper presents a comparative assessment of the cost and quality of treatment of tannery wastewater in India by two common effluent treatment plants (CETPs) constructed for two tannery clusters, at Jajmau (Kanpur) and at Unnao in the state of Uttar Pradesh, India. The Jajmau plant is upflow anaerobic sludge blanket (UASB) process-based, while the Unnao plant is activated sludge process (ASP)-based. Investigations indicated that the ASP-based plant was superior in all respects. Total annualized costs, including capital and operation and maintenance costs, for the UASB and ASP plants were Rs. 4.24 million/million liters per day (MLD) and Rs. 3.36 million/MLD, respectively. Land requirements for the two CETPs were 1.4 hectares/MLD and 0.95 hectares/MLD, respectively. Moreover, the treated UASB effluent had higher biochemical and chemical oxygen demand (BOD/COD) and considerable amounts of other undesirable constituents, like chromium (Cr) and sulfide, as compared with the ASP effluent, which had lower BOD/COD and negligible concentration of sulfide and Cr. Sludge production from the UASB-based plant was also higher at 1.4 t/day/MLD, in comparison to the sludge production of 0.8 t/day/MLD for the ASP-based plant. Also, the entire sludge produced in the UASB-based plant was Cr-contaminated and, hence, hazardous, while only a small fraction of the sludge produced in the ASP-based plant was similarly contaminated. The results of this study are at variance with the conventional wisdom of the superiority of anaerobic processes for tannery waste-water treatment in tropical developing countries like India.     

Effect of pressure and temperature on the hydropyrolysis of cotton residue

With growing concerns of fossil fuel resources availability and the volatility of crude oil price, it is becoming imperative day by day to utilize the renewable sources of energy in a sustainable, environment friendly and energy efficient manner. India is the world’s second largest producer of cotton after China. India also has several agricultural and forest residues, and cotton residue is one of the most abundant agricultural residues after rice and wheat residues. The hydropyrolysis of cotton residues has been carried out at various pressures (1, 20 and 40 bar) and temperatures (300, 350, 400 and 450 °C). The effects of temperature and pressure have been studied to understand their yield patterns, and it has been observed that 20 bar pressure and 400 °C are the optimum conditions. The thermogravimetric analysis shows that cotton residue has two significant decomposition temperatures. The SEM, XRD patterns and FT-IR spectra clearly indicate the decomposition of the macromolecular structure of the cotton residue and formation of low molecular weight hydrocarbons suitable for various applications.     

Connecting the dots: mapping habitat connectivity for tigers in central India

Large connected landscapes are paramount to maintain top predator populations. Across their range, tiger (Panthera tigris) populations occur in small fragmented patches of habitat, often isolated by large distances in human-dominated landscapes. We assessed connectivity between 16 protected areas (PAs) in central India, a global priority landscape for tiger conservation, using data on land use and land cover, human population density, and transportation infrastructure. We identified and prioritized movement routes using a combination of least-cost corridor modeling and circuit theory. Our analyses suggest that there are several opportunities to maintain connectivity in this landscape. We mapped a total of thirty-five linkages in the region and calculated metrics to estimate their quality and importance. The highest quality linkages as measured by the ratio of cost-weighted distance to Euclidean distance are Kanha–Phen/Bandhavgarh–SanjayGhasidas/Melghat–Satpura, and cost-weighted distance to least-cost path length are Nawegaon–Tadoba/Achanakmar–SanjayGhasidas/Kanha–Phen. We used current flow centrality to evaluate the contribution of each PA and linkage toward facilitating animal movement. Values are highest for Kanha and Pench tiger reserves, and the linkages between Kanha–Phen, Kanha–Pench, and Pench–Satpura, suggesting that these PAs and linkages play a critical role in maintaining connectivity in central India. In addition, smaller areas such as Bor, Nawegaon, and Phen have high centrality scores relative to their areas and thus may act as important stepping stones. We mapped pinch points, which are sections of the linkages where tiger movement is restricted due to unfavorable habitat, transportation networks, human habitation, or a combination of factors. Currently, very limited data exist on tiger movement outside of PAs to validate model results. Regional-scale connectivity mapping efforts can assist managers and policy makers to develop strategic plans for balancing wildlife conservation and other land uses in the landscape.     

Case studies on biological treatment of tannery effluents in India

This paper presents a comparative assessment of the cost and quality of treatment of tannery wastewater in India by two common effluent treatment plants (CETPs) constructed for two tannery clusters, at Jajmau (Kanpur) and at Unnao in the state of Uttar Pradesh, India. The Jajmau plant is upflow anaerobic sludge blanket (UASB) process-based, while the Unnao plant is activated sludge process (ASP)-based. Investigations indicated that the ASP-based plant was superior in all respects. Total annualized costs, including capital and operation and maintenance costs, for the UASB and ASP plants were Rs. 4.24 million/million liters per day (MLD) and Rs. 3.36 million/MLD, respectively. Land requirements for the two CETPs were 1.4 hectares/MLD and 0.95 hectares/ MLD, respectively. Moreover, the treated UASB effluent had higher biochemical and chemical oxygen demand (BOD/ COD) and considerable amounts of other undesirable constituents, like chromium (Cr) and sulfide, as compared with the ASP effluent, which had lower BOD/COD and negligible concentration of sulfide and Cr. Sludge production from the UASB-based plant was also higher at 1.4 t/day/MLD, in comparison to the sludge production of 0.8 t/day/MLD for the ASP-based plant. Also, the entire sludge produced in the UASB-based plant was Cr-contaminated and, hence, hazardous, while only a small fraction of the sludge produced in the ASP-based plant was similarly contaminated. The results of this study are at variance with the conventional wisdom of the superiority of anaerobic processes for tannery wastewater treatment in tropical developing countries like India.     

Toxicological evaluation of constructed wetland habitat sediments utilizing 10-day sediment toxicity test and bacterial bioluminescence

A toxicological evaluation was conducted on wetland habitats created as a result of run-off from agricultural areas. These temporary wetlands were created by using drop pipes as a means of reducing erosional cutting in agricultural fields. Toxicity bioassays utilizing bacterial bioluminescence and Hyalella azteca were used to assess sediment pore water and whole sediment, respectively. Inhibition of bacterial bioluminescence was initially used to determine relative toxicities of pore water from ten wetland sites. Constructed wetland sites were compared to the University of Mississippi Biological Field Station, a relatively pristine reference site. The H. azteca ten day sediment toxicity test was utilized to assess sediment from four selected sites using survival and growth as toxicological endpoints. Results from the toxicological evaluation, along with extensive ecological evaluations, were used to assess the best approach for implementation of temporary wetland habitats with existing agricultural practices.     

Metallic components of traffic-induced urban aerosol, their spatial variation, and source apportionment

This study proposes a practical method to estimate elemental composition and distribution in order to attribute source and quantify impacts of aerosol particles at an urban region in Kolkata, India. Twelve-hour total particulates were collected in winter (2005–2006) and analyzed by energy-dispersive X-ray fluorescence technique to determine multi-elemental composition, especially trace metals. The aerosols consist of various elements including K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, and Pb which exhibit significant concentration at various sites (p?<?0.05). The concentration of different metallic elements were found in the order of Zn ?> ?Pb ?> ?Ni ?> ?Cu ?> ?Cr ?>? Co. Statistical multivariate analysis and correlation matrix analyses were performed for factor identification and consequent source apportionment. Contour profiles demonstrate spatial variation of elemental compositions indicating possible source contribution along with meteorological influences. Spatial differences were clearly most significant for Zn, Ni, Pb, and Cu reflecting the importance of anthropogenic inputs, primarily from automobile sources.