Journal of Hazardous, Toxic, and Radioactive Waste

The decolorization of the synthetic dye solution containing reactive blue 19 dye was performed by the Fenton and the photo-Fenton processes. The effect of the dose of the hydrogen peroxide and the ferrous ions and the solution pH on the rate of decolorization was studied and the optimum conditions were obtained. The maximum color reductions of 93.3 and 97.5% were obtained after 360 min of oxidation at the optimum conditions (solution pH 3, ${\mathrm{H}}_2{\mathrm{O}}_{2}50\mathrm{mg}/\mathrm{L}$, ${\mathrm{Fe}}^{2+}4\mathrm{mg}/\mathrm{L}$) by the Fenton and the photo-Fenton processes, respectively. The experimental data were analyzed using the first-order, second-order and Behnajady-Modirshahla-Ghanbery (BMG) kinetic models, and the kinetic data were in good agreement with the BMG model. Experiments were also performed to treat the real textile industry effluent containing the reactive blue 19 dye, and the color reductions of 84 and 97% was obtained after 540 min of the treatment by the Fenton and the photo-Fenton processes, respectively.

In India, presently 85 existing thermal power plants (TPPs) produce 118 million metric tons of fly ash per year, which is projected to exceed 170 and 440 million metric tons/year by Years 2012 and 2030, respectively. This huge quantity of fly ash not only poses the problems of environmental concerns but occupies large areas of land for its dumping, which needs urgent and appropriate measures for its safe disposal and gainful utilization on sustainable basis. Based on the detailed study on the bulk utilization of pond ash in agriculture and forestry sectors under different agroclimatic conditions and soil types for last 2 decades, it has been found that pond ash has a very good potential for the utilization on bulk scale as liming agent, soil conditioner, source of essential plant nutrients, and also for boosting the growth and yields of a variety of crops and growth performance of plant species. Some field-scale studies carried out especially in the wastelands of State Agriculture Research Farm and farmers’ fields are discussed in the present paper. The influence of critical parameters on the yield of wheat crops cultivated in different soil types and agroclimatic conditions is discussed. Further, an attempt has been made to develop a three-layer feed-forward artificial neural network (ANN) model, which is inherently trained using error back-propagation algorithm. The results evince that the predictions from the ANN model are in good qualitative and quantitative agreement with the field observations, thereby validating the applicability and accuracy of the developed ANN model.

Study on the adsorption of phenol onto activated carbon prepared from Babul (Acacia nilotica) sawdust (BAC), a waste from sawmill, is presented in this paper. The effect of various parameters such as adsorbent dose ($m$), initial pH (${\mathrm{pH}}_0$), contact time ($t$), initial concentration ($C_o$), and temperature ($T$) on adsorption capacity of BAC was tested using batch adsorption experiments. The kinetic study was performed by using different kinetic models, viz pseudo first, pseudo second order, and intraparticle diffusion. Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherm equations were used to find the suitable and well-describing experimental isotherm data. The adsorption of phenol onto BAC follows the pseudo second order kinetic model, and equilibrium adsorption data follow the Redlich-Peterson and Freundlich isotherm equation. The maximum removal of phenol was found to be about 83% for the initial concentration of $50\mathrm{mg}/\mathrm{L}$ and about 50% for the higher initial concentration of $500\mathrm{mg}/\mathrm{L}$ at $10\mathrm{kg}/{\mathrm{m}}^3$ of BAC dose and normal temperature of 303 K. Thermodynamic study illustrates that the adsorption of phenol onto BAC is a completely exothermic, spontaneous process, and the adsorption decreases with the increase in temperature.

This paper presents an assessment of individual and societal risk associated with the effects of explosions and fires in the petroleum oil storage terminal of Indian Oil Corporation Limited (IOCL), Jaipur, India, that occurred on October 29, 2009. Eleven fatalities and a property loss of approximately U.S. $60 million were reported. The maximum risk level at a distance of around 100 m from the release point is ${10}^{-4}\mathrm{per}\mathrm{year}$. The next risk level, i.e., ${10}^{-5}\mathrm{per}\mathrm{year}$ is at a distance of 280 m within the terminal boundary. This paper demonstrates that the individual risk inside the terminal for various categories of personnel is in the range of ${10}^{-5}$ to ${10}^{-6}\mathrm{per}\mathrm{year}$. Moreover, $F/N$ curve (where $N$ is the number of fatalities, and $F$ is the frequency of $N$ or more fatalities) indicating societal risk is in the so-called as low as reasonably practicable region. Thus the total risk at the terminal does not lie in the unacceptable region, but in the as low as reasonably practicable region where substantial measures for a risk reduction were needed. The consequences in and around the terminal were high, which might be due to the failure or absence of certain precautionary measures. The paper is useful to assess the fire and explosion risk of a petroleum oil storage terminal to avoid major accidents.

This study describes pot experiments that were conducted to investigate the plant species considered suitable for phytoremediation of mixed contaminated soil. Mixed contaminated soil was prepared by spiking silty clay soil with organic contaminants (naphthalene and phenanthrene) and heavy-metal contaminants (lead, cadmium, and chromium). Twelve species of plants were grown in pots filled with contaminated soil. Plants grown in uncontaminated soil were used as control. Results showed that five plant species (sunflower, oat plant, rye grass, tall fescue, and green gram) were able to survive the mixed contaminated conditions. The oat plant had better growth characteristics and minimal stress signs in mixed contaminated soil than the other species. Even though sunflower plants did not show the best growth characteristics, the maximum contamination removal from the soil was achieved by these plants. Exchangeable heavy metals were also reduced in the soil that was planted with sunflower plants compared with contaminated unplanted soil.

The large-strain consolidation behavior of a uranium tailings storage facility was investigated by analyzing survey data (bathymetric and topographic) from 1996 to 2008, laboratory testing of the mill tailings using a consolidation test system, and history matching of the deposited tailings using numerical modeling. The average cumulative consolidated height in the Deilmann Tailings Management Facility (DTMF) can be divided into four distinct stages: (1) rapid increase of $13\mathrm{m}/\mathrm{year}$ from 1996 to 1999, (2) steady height increase of $2.5\mathrm{m}/\mathrm{year}$ over the next 3 years, (3) relatively large height increase of approximately $7\mathrm{m}/\mathrm{year}$ from 2002 to 2005, and (4) a steady height increase of $3\mathrm{m}/\mathrm{year}$ over the next 3 years. During the large-strain consolidation test of the investigated mill tailings (${\sigma }^{\prime }$ of 0.3–8 kPa), the void ratio decreased from 5.8 to 3.3 and the solids content increased from 32 to 46%. The vertical hydraulic conductivity was found to range from $6\times {10}^{-7}$ to $1\times {10}^{-7}\mathrm{m}/\mathrm{s}$. The numerical modeling results closely approximated the consolidated tailings elevations and effective stress profiles in the DTMF over the period of 1996 to 2008. The field effective stress values correlated quite well with the modeling results, thereby validating the predictions. Overall, the results indicate that the effective stress increased from 0 kPa at the surface to the following values at the DTMF bottom: 200 kPa in 1999, 530 kPa in 2005, and 680 kPa in 2008.

Flame-retardant polymer nanocomposites exhibiting remarkably improved flame-retardant and environmentally friendly properties have been widely utilized to replace traditional halogenated fire retardants. In this review, flame retardant mechanisms of polymer nanocomposites such as barrier effect, char formation, three-dimensional nanostructure, and radical trapping, are discussed to explain how nanomaterials can be incorporated in a polymer to reduce the polymer’s flammability. Properties that are critical in governing the flame-retardant mechanisms of polymer nanocomposites are discussed in this review. Specifically, category, surface property, and concentration of nanomaterials are critical in affecting flame-retardant properties of polymer nanocomposites and are reviewed in detail. Nanocomposite categories, especially, silicates (clays), inorganic hydroxides, carbonaceous materials, metal oxides, polysilsequioxanes, and their combinations are well described. The use of synergism and surface modification of nanomaterials are important strategies for optimizing flame retardancy of polymer nanocomposites. The peak heat-release rate (HRR), the most important parameter for predicting fire hazard, is widely involved in this review.

The effectiveness of anaerobic wastewater treatment is limited by pollutants in industrial wastewaters inhibiting microorganisms, leading to digester failure. Acclimatization enables the microorganisms to develop the capacity to degrade them faster, preventing reactor failure. The present study focuses on the acclimatization of anaerobic sludge to treat two pollutants, chromium (VI) and 4-chlorophenol (4-CP), in two separate batch reactors. Microbial community profiles were obtained to find their effects on microbial populations. Both chemical and microbial data indicated inhibition of biogas production. A 50% reduction in methane concentration was observed at 150 ppm of Cr (VI), whereas for 4-CP, it was observed at 200 ppm. Sulfate-reducing bacteria present in the anaerobic sludge helps to remove heavy metals by facilitating the formation of insoluble metal sulfides. The effect of their presence in an anaerobic system containing 150 ppm Cr (VI) was studied by adding 30-mM sodium molybdate, which inhibited the sulfate reducing bacteria.

The presence of antibiotic residues in the environment is an emerging pollution issue due to their uninterrupted and unrestrained release into the environment and their harmful effects even at low concentrations. The occurrence and fate of these trace contaminants during wastewater treatment are key issues in the recycling of water resources. One of the major concerns is the presence of antibiotics in drinking water subsequent to wastewater treatment. Several processes have been adopted to degrade or eliminate antibiotics efficiently. This paper provides an insight on efficacy of various advanced oxidation processes for the removal of antibiotics and its crucial link to their physical-chemical properties and degradation.

The recirculation of leachate is a common strategy to accelerate the decomposition of municipal solid waste in landfills. In this study, leachates from a conventional landfill cell without supplemental liquid addition (Control cell), a new landfill area that had a piping network installed as waste was being placed (As-Built cell), and a conventional landfill that was modified to allow for the recirculation of liquids (Retrofit cell) were monitored at the outer loop landfill bioreactor (OLLB) in Louisville, Kentucky. In general, leachates from the Retrofit cells were statistically different from leachates from the As-Built and Control cells. This is likely because the waste in Retrofit cells was about 6 years old when liquids were first introduced and the waste had already reached a more mature state prior to supplemental liquids addition. Based on time series data, the Retrofit cells, which received nitrified leachate, did not show signs of accelerated waste decomposition based on the leachate chemistry. In contrast, there were significant differences in parameters affected by waste biodegradation [temperature, pH, biological oxygen demand (BOD), chemical oxygen demand (COD), volatile organic acid (VOA), total organic carbon (TOC)] between the As-Built and Control cells, suggesting that the introduction of liquids accelerated waste decomposition in the As-Built cells. Trends were generally similar in the As-Built cells compared to the Control cells, even though concentrations of some parameters were higher in the As-Built cells. The elevated temperature in the As-Built cells suggests more active decomposition.

Regulations that dictate the management of asbestos-containing materials (ACM) and lead-based paint (LBP) debris in the United States require these materials to be managed in a specific manner at the job site to reduce potentially hazardous exposure to site workers, and the disposal of the materials is regulated through notification and special handling requirements. However, management of ACM and LBP from residential projects are afforded some exemptions in U.S. regulations; thus, some quantity of these materials may be delivered to a disposal facility, thus representing a potential exposure concern for landfill workers because ACM and LBP cannot be detected through visual inspection. A novel characterization framework was developed to quantify the occurrence of ACM and LBP in discarded construction and demolition (C&D) debris. A total of 266 loads of debris and 307 samples of potential ACM were collected from 10 landfills in Georgia with a total of four detections of asbestos (frequency of 1.3%). A total of 487 painted surfaces of incoming waste were analyzed for lead using a handheld X-ray fluorescence device, with a total of 70 positive detections (defined as a concentration greater than $1\mathrm{mg}/{\mathrm{cm}}^2$). The mass of debris corresponding to the positive lead detections comprised a mass fraction of 1.4% of all waste that was sampled. The results represent the most extensive sampling and analysis of ACM and LBP in discarded C&D debris, demonstrating that the U.S. federal regulatory scheme for management of ACM and LBP are generally effective at limiting indiscriminate disposal of ACM and LBP. The results were also likely impacted by the timeframe of ACM and LBP use in the United States and the typical service life of construction materials that used ACM and LBP. The framework developed in this study can be applied at other disposal and recycling facilities to characterize other waste streams of interest that are difficult to assess through visual approximation such as specific metal alloys.