Resource recovery through bioremediation of wastewaters and waste carbon by microalgae: a circular bioeconomy approach

Environmental Science and Pollution Research - Microalgal biomass–based biofuels are a promising alternative to fossil fuels. Microalgal biofuels’ major obstacles are the water and...     

Test methodology for determining the incendiary nature and electrostatic discharge characteristics of plastic surfaces

This experimental study was originally designed to quantify the electrostatic characteristics of offshore grade fiberglass reinforced plastic (FRP) pipes [Dastidar, A. G., Dahn, C. J., Cole, B. W., & Lo, K. H. (2005a). Electrostatic characteristics of FRP pipes. In Fourth international conference on composite materials for offshore operation, Houston, TX, Oct 4–6, 2005]. Discharge energies were measured from the sample surfaces for each test condition after an aggressive corona charging of up to −40 kV. While the measured values of total discharge energy were relatively high for some samples, the energy in the first peak was significantly lower. The first peak energy is thought to be the most significant measure in establishing the potential for incendive events.

To further quantify the incendive potential of discharges from FRP pipes, a unique test method was developed [Dastidar, A. G., Dahn, C. J., Cole, B. W., & Lo, K. H., (2005b). Incendiary nature and electrostatic discharge characteristics of FRP pipes. In Fourth international conference on composite materials for offshore operation, Houston, TX, Oct 4–6, 2005]. The methodology has been expanded to include other FRP components. This paper describes the test method and the test results obtained for testing several FRP structures and materials (pipes, grill work, railing etc.). The significance of the experimental results to industry is also discussed.     

Sustainable solid waste management: An integrated approach for Asian countries

Solid waste management (SWM) has been an integral part of every human society. The approaches for SWM should be compatible with the nature of a given society, and, in this regard, Asian countries are no exception. In keeping with global trends, the systems are being oriented to concentrate on sustainability issues; mainly through the incorporation of 3R (reduce, reuse and recycle) technologies. However, degree and nature of improvements toward sustainability are varying and depend on the economic status of a country. High-income countries like Japan and South Korea can afford to spend more to incorporate 3R technologies. Most of the latest efforts focus on “Zero Waste” and/or “Zero Landfilling” which is certainly expensive for weaker economies such as those of India or Indonesia. There is a need to pragmatically assess the expectations of SWM systems in Asian countries. Hence, in this paper, we analyze the situation in different Asian countries, and explore future trends. We conceptually evaluate issues surrounding the sustainability of SWM. We propose a multi-pronged integrated approach for improvement that achieves sustainable SWM in the context of national policy and legal frameworks, institutional arrangement, appropriate technology, operational and financial management, and public awareness and participation. In keeping with this approach, a generic action plan has been proposed that could be tailored to suit a situation in a particular country. Our proposed concept and action plan framework would be useful across a variety of country-specific scenarios.     

Changes in lipid profiles of liver microsomes of rats following intratracheal administration of DDT or endosulfan

Abstract

The effect of intratracheal administration of DDT (5 mg/100 g body weight) or endosulfan (1 mg/100 g body weight) to rats for three consecutive days, has been studied on liver lipid metabolism. The administration of DDT but not endosulfan significantly increased the liver weight and the microsomal protein contents. Both DDT and endosulfan treatments significantly increased the contents of microsomal phosphatidylcholine (PC), total‐free‐ and esterified cholesterol. The distribution of unsaturated fatty acids of microsomal PC and PE was increased by DDT treatment. The intratracheal administration of DDT caused fatty infiltration of liver which was probably due to increased synthesis of triglycerides (TG). This is supported by the increased incorporation of radioactive palmitate‐l‐¹⁴C into microsomal TG. However, the increased incorporation of palmitate‐l‐¹⁴C into microsomal PC and phosphatidylethanolamine (PE) after the DDT treatment, was due to the increased transacylation reaction supported by the decreased activity of microsomal phospholipase A. The intratracheal adminstration of endosulfan did not has pronounced effect on liver fatty infiltration, or transacylation reaction in microsomal PC and PE. However, the results have shown that the treatments of DDT or endosulfan increased the PC contents and the incorporation of radioactive [methyl‐³H]choline into PC of microsomes, resulting the increased synthesis of PC via CDPcholine pathway. Thus, the intratracheally administered DDT or endosulfan to rats showed that both the insecticides cause manifestations in the biochemistry of microsomal membrane lipids, although the effects of DDT being more pronounced. Therefore, the translocation effects of these insecticides or metabolites from lung to liver is established.     

Induction of cytochrome p‐450 and phosphatidylcholine synthesis by endosulfan in liver of rats : Effect of quality of dietary proteins

Abstract

Administration of endosulfan significantly increased microsomal protein, cytochrome P‐450 content and the activity of aminopyrine N‐demethylase. Effect of endosulfan and actinomycin D either alone or together on microsomal protein, cytochrome P‐450, NADPH cytochrome c reductase, aniline hydroxylase, aminopyrine N‐demethylase, phosphatidylcholine content, incorporation of ³H‐choline and ¹⁴C‐methionine were studied in rats given amino acid deficient and supplemented diets. Administration of endosulfan significantly increased the above parameters in both the dietary groups, whereas administration of actinomycin D did not have any effect in rats fed supplemented diets, however, significant decrease in the PC and the incorporation of choline and methionine into PC of rats fed deficient diet were observed. A positive correlation in the effect of endosulfan on hepatic mixed function oxidase activity and hepatic phosphatidylcholine is observed.     

Chemical Approach to Study the Environmental Implications of Humic Acid and Gamma-Hch Interaction

Pesticide-humic interactions are known to have environmental significance in modifying the toxicity and mobility of agricultural chemicals. to test this, interaction between gamma-hexachlorocyclohexane (gamma-HCH) released from the sand coated with gamma-HCH and humic acid was investigated using thin layer chromatography and spectral studies such as UV (ultraviolet), IR (infrared), mass and FAB (fast atom bombardment) mass spectrometry. These studies revealed the evidence of loose interchelation between gamma-HCH and humic acid. the significance of the results in relation to detoxification of gamma-HCH in aquatic ecosystems are discussed.     

Comparison of drinking water,raw rice and cooking of rice as arsenic exposure routes in three contrasting areas of West Bengal,India

Remediation aimed at reducing human exposure to groundwater arsenic in West Bengal, one of the regions most impacted by this environmental hazard, are currently largely focussed on reducing arsenic in drinking water. Rice and cooking of rice, however, have also been identified as important or potentially important exposure routes. Quantifying the relative importance of these exposure routes is critically required to inform the prioritisation and selection of remediation strategies. The aim of our study, therefore, was to determine the relative contributions of drinking water, rice and cooking of rice to human exposure in three contrasting areas of West Bengal with different overall levels of exposure to arsenic, viz. high (Bhawangola-I Block, Murshidibad District), moderate (Chakdha Block, Nadia District) and low (Khejuri-I Block, Midnapur District). Arsenic exposure from water was highly variable, median exposures being 0.02 μg/kg/d (Midnapur), 0.77 μg/kg/d (Nadia) and 2.03 μg/kg/d (Murshidabad). In contrast arsenic exposure from cooked rice was relatively uniform, with median exposures being 0.30 μg/kg/d (Midnapur), 0.50 μg/kg/d (Nadia) and 0.84 μg/kg/d (Murshidabad). Cooking rice typically resulted in arsenic exposures of lower magnitude, indeed in Midnapur, median exposure from cooking was slightly negative. Water was the dominant route of exposure in Murshidabad, both water and rice were major exposure routes in Nadia, whereas rice was the dominant exposure route in Midnapur. Notwithstanding the differences in balance of exposure routes, median excess lifetime cancer risk for all the blocks were found to exceed the USEPA regulatory threshold target cancer risk level of 10⁻⁴–10⁻⁶. The difference in balance of exposure routes indicate a difference in balance of remediation approaches in the three districts.     

Numerical Modeling of the Thermal Boundary Layer Near a Synthetic Crude Oil Plant

Production from the world’s largest tar sands plant began in July 1978. Under the permit to construct the plant, Syncrude Canada Ltd. is permitted to emit 287 long tons of SO₂/day as long as Alberta’s Clean Air Regulations are not Violated. In order to predict such violations for emission control purposes, it is important to know the diurnal variation of the thermal boundary layer (TBL) height. In this paper, a numerical model for the prediction of TBL height as a function of time of day is given based on the solution of appropriate conservation equations relating both the heat flux and the temperature jump across the inversion layer to the height of the TBL. The resulting equations are solved by the Runge-Kutta method. The model is tested against the field data collected as part of a base-line data acquisition program. A comparison is also made of two different methods (kink method and conventional method) to calculate thermal boundary heights from the mini-sonde data. Problems in the use of the results of TBL heights using these two methods for predicting pollution potential near the plant are also discussed.     

Use of adjuvants to minimize leaching of herbicides in soil

Excessive leaching of herbicides affects their efficacy against target weeds and results in contamination of groundwater. Use of adjuvants that can weakly bind herbicides and in turn release them slowly is a valuable technique to prolong the efficacy of herbicides and to minimize their leaching into groundwater. Effects of activated charcoal, three humic substances (Enersol SP 85%, Enersol 12%, and Agroliz), or a synthetic polymer (Hydrosorb) on the leaching of bromacil, dicamba, and simazine were investigated in leaching columns using a Candler fine sand (Typic Quartzipsamment). The addition of adjuvants had no harmful effects on physical properties of the soil as evident from lack of its affects on water percolation. When no adjuvants were used, 69%, 37%, and 4% of applied dicamba, bromacil, and simazine, respectively, were leached in the first pore volume of leachate (⋍3.2 cm rainfall). With five pore volumes of leachate (⋍16 cm rainfall), bromacil and dicamba were leached completely and only 80% of simazine was leached. Using Enersol 12% adjuvant resulted in a 13%–18% reduction in leaching of dicamba and bromacil in five pore volumes of leachate. The leaching of simazine was significantly decreased when any of the five adjuvants mentioned above were used. However, the decrease in leaching was significantly greater when using Enersol SP 85% or Enersol 12% (24%–28%) than when using the other adjuvants (12%–16%).     

Explosibility of polyamide and polyester fibers

The current research is aimed at investigating the explosion behavior of hazardous materials in relation to aspects of particulate size. The materials of study are flocculent (fibrous) polyamide 6.6 (nylon) and polyester (polyethylene terephthalate). These materials may be termed nontraditional dusts due to their cylindrical shape which necessitates consideration of both particle diameter and length. The experimental work undertaken is divided into two main parts. The first deals with the determination of deflagration parameters for polyamide 6.6 (dtex 3.3) for different lengths: 0.3 mm, 0.5 mm, 0.75 mm, 0.9 mm and 1 mm; the second involves a study of the deflagration behavior of polyester and polyamide 6.6 samples, each having a length of 0.5 mm and two different values of dtex, namely 1.7 and 3.3. (Dtex or decitex is a unit of measure for the linear density of fibers. It is equivalent to the mass in grams per 10,000 m of a single filament, and can be converted to a particle diameter.) The explosibility parameters investigated for both flocculent materials include maximum explosion pressure (P_max), size-normalized maximum rate of pressure rise (K_St), minimum explosible concentration (MEC), minimum ignition energy (MIE) and minimum ignition temperature (MIT). ASTM protocols were followed using standard dust explosibility test equipment (Siwek 20-L explosion chamber, MIKE 3 apparatus and BAM oven). Both qualitative and quantitative analyses were undertaken as indicated by the following examples. Qualitative observation of the post-explosion residue for polyamide 6.6 indicated a complex interwoven structure, whereas the polyester residue showed a shiny, melt-type appearance. Quantitatively, the highest values of P_max and K_St were obtained at the shortest length and finest dtex for a given material. For a given length, polyester displayed a greater difference in P_max and K_St at different values of dtex than polyamide 6.6. Long ignition delay times were observed in the BAM oven (MIT measurements) for polyester, and video framing of explosions in the MIKE 3 apparatus (MIE measurements) enabled observation of secondary ignitions caused by flame propagation after the initial ignition occurring at the spark electrodes.