Global NEST Journal

Oil spill cleanup is a complex and expensive activity. There are several commonly used techniques available today. The paper suggests criteria for the selection of the best available technique that could be employed in case of oil spills in the Mediterranean Sea under specific circumstances, i.e. calm sea and presence of marine protected areas, in order to prevent pollution. Not all the available techniques could be considered. Only three of them could be selected, as these allow the preservation of natural areas, as well as the protection of threatened species and their habitats. The Analytic Hierarchy Process method has been preferred among the great variety in multi-criteria decision making tools for the selection of the best available technique. This is a widespread decision support tool suitable for the selection of the best alternative solution to a particular problem. Twenty professionals with different expertise evaluated, through pair-wise comparisons, the alternative options to choose in a protected area. The selected emergency cleanup technique must be readily available and operational in a short time. The results give a preference to new sorbents, followed closely by the magnetic nanocomposites technique.

One of the major challenges faced by researchers is to recycle industrial wastes in a manner that reduces their environmental impact in nature. An experimental study was carried out to determine the suitability of using chopped tire rubber as reinforcements in green and sustainable geopolymer concrete, with the purpose of using them as nonstructural products. The geopolymer mixture was made by mixing of fly ash powder, fine aggregate, and Superplasticizer in Na2SiO3/NaOH solution. Mixtures were divided into four different groups, with constant water to fly ash ratio of 0.12 and alkaline dosage of 45% by weight of fly ash, based on the recycled chopped tire rubber (CTR) content: 0, 10, 20, and 30% by volume of fine aggregate with two maximum sizes (2 and 4mm). Hardened properties of resulted geopolymer like compressive strength, density; and ultrasonic pulse velocity were examined at 28d. Besides that, X-Ray diffractometer and Scanning Electron Microscope were used in order to observe the microstructure of the resulted geopolymer concrete. In view of the consequences for this study, it is preferable to replace no more than 10% of fine aggregate in geopolymer concrete by CTR. In addition, according to SEM photographs, increasing the CTR content more voids will be pronounced and thus, decreasing the mechanical performance.

The present study analyses the various uncertainties and nonstationarity in the streamflow projections of Subarnarekha river basin in Eastern India using two widely used hydrological climate models: 1) general circulation model (GCM), and 2) forcing climate change scenarios. These two climate models are used to force the ArcSWAT model. Subsequently this model is calibrated using SUFI-2 optimization technique. The downscaled and bias-corrected data from an ensemble of 10 climate projections with representative concentration pathways (RCP) 4.5 and 8.5 scenarios (five each) were used in first model, whereas in second model a total of 63 (7 perturbed precipitations and 9 perturbed temperatures) combinations of hypothetical climate change scenarios were used. The results show very good correlation during monthly calibration time steps and relatively good agreement between the observed and simulated streamflows in daily calibration time steps. The uncertainties are expressed in probabilistic terms using probability density function (PDF) and cumulative distribution function (CDF) as they provide significant information for decision process in climate change adaptation in the river basin. The uncertainties associated with climate models, return periods and streamflow extremes are also analysed in the present work. The RCP 8.5 scenarios seem more appropriate than RCP 4.5 scenarios in quantifying the uncertainties under nonstationarity assumptions. The mean values of water balance components and their percentage variation for both historic and future periods reveal that the water balance components get affected significantly due to climate change in a future period. Consequently, the streamflows are likely to decline in the river basin. The present study also highlights the comprehensive approaches that are being planned to facilitate adaptation to climate change as well as those that are specific to the water resources management in the study region. The findings in this work are useful for overall well-being of people in the study area.

The present study observed the removal of the organic content from the real effluent water produced by the oilfields. The proposed treatment process was the adsorption technique using the moringa peels as adsorbing agent. The effect of processing parameters such as adsorbent dosage, contact time and pH has been investigated using the batch adsorption method. The Langmuir isotherm provided a better fit for the adsorption equilibrium data than the Freundlich isotherm. It was observed that organic content adsorption was dependent on pH. The maximum removals of organic content were 65.4 % and 94.1% for moringa and activated moringa peels respectively at pH =3, 120 min, 1.5 gm dose. The outcome of this study exposes that activated moringa peels might be rummage-sale as a low-cost adsorbent for the removal of organic content from produced water.