• Energy Research
• 6. Clean water close

The cover of a disposal cell is an important element in the long-term stability of a reclaimed uranium tailings site. The cover is generally comprised of a radon barrier, filter, and surface erosion barrier. A study is conducted to investigate the drainage and erosion potential between the filter and radon barrier layer in response to surface water flows over a layer of riprap. A cover system is physically modeled in a hydraulics laboratory. The experimental program evaluated the interstitial velocity potential through four filters, the erosion and sediment transport potential from the radon barrier, and the filter drainage rate after passage of the surface runoff hydrograph. The results indicated that the use of traditional filter criteria to bed riprap is extremely conservative and restricts drainage. The grain size of the filter materials should be increased to enhance drainage when placed on flat (\IS\N ≤\N 5%) slopes. A relationship is presented for estimating the drainage velocity potential through a filter layer as a function of slope and gradation. A new filter criteria should be developed for overtopping flow conditions.

Abstract A new formulation for the evaporation, flashing, condensation processes taking place in the effects of thermal desalination systems which simulates the operation of both forward and parallel/cross configurations is coupled with an exergo-economic model based on the SPECO method. The thermo-economic model uses accurate properties for the seawater, brine, pure water and vapour and is solved with an equation solver which does not require the development of a specific solution algorithm as in most previous studies. This flexible model is used to analyze the influence of the number of effects N and the temperature difference ΔT e between effects on the technical and economic performance of multi-effect desalination systems with ejector vapour compression. In particular, it is shown that the performance calculated by an earlier black-box approach is not attainable by technically and economically realistic systems. It is also shown that for each feed configuration and a given number of effects there exists an optimum value of ΔT e which minimizes the cost of the produced potable water. This last result forms the basis of a procedure that combines black-box results with the optimum value of ΔT e and can be used to select the appropriate system for any specific application.

Abstract: The dynamics of reformation and replacement of gas hydrates were studied under nonequilibrium conditions. It was found that the reformation of gas hydrates is largely affected by the state of the gas‐water system and the restarting temperature. This suggests that the effects are caused by changes in the structure of the aqueous solution at a molecular level. Pure samples of CH4 gas hydrate were synthesized from ice crystals and the dissociated solution using the reformation method. Replacement of CO2 gas hydrate is achieved within a short duration in the solid‐phase sample of CH4 gas hydrate, if the pressure and temperature is precisely controlled in a pressure vessel.

Sustainability of agro-food supply chains has recently become the subject of greater interest from consumers, firms, governmental organizations and academia as the environment continues to deteriorate. One of the most critical factors influencing the sustainability of an agro-food supply chain is its network design. A particularly challenging aspect in this context is the broad range of influencing indicators associated with the Triple Bottom Line (TBL) of sustainability that need to be considered. However, many of these indicators could not be fully integrated or measured by single-step optimization problems. This paper presents a critical literature review of operational research methods for the design of sustainable supply chains. A novel two-stage hybrid solution methodology is proposed. In the first stage, a partner selection is performed using a hybrid multi criteria decision making based on Analytic Hierarchy Process (AHP) method and the Ordered Weighted Averaging (OWA) aggregation method. The result obtained in the first stage is used in the second stage to develop a multi-objective mathematical model to optimize the design of the supply chain network. This approach allows the simultaneous consideration of all three dimensions of sustainability including carbon footprint, water footprint, number of jobs created and the total cost of the supply chain design. The proposed approach generates a Pareto frontier to aid users in making decisions. Numerical experiments are completed utilizing data from an agro-food company to demonstrate the efficiency and effectiveness of the proposed solution methodology. The analyzes of the numerical results provide important organizational, practical and policy insights on (1) the impact of financial and environmental sustainability on supply chain network design (2) the tradeoff analysis between environmental emission, water footprint, societal implications and associated cost for making informed decision on supply chain investment.

The objective of the study was to evaluate the effect of two types of treated sewage sludge as soil amendment, composted with pruning wastes (CP) and thermally dried (ST) on the production of ten woody perennials species for energy purposes. The species used were: Paulownia tomentosa (princess tree), Populus x euramericana (Canadian poplar), Ulmus minor (field elm, tree clones), Ulmus laevis (European white elm), Prunus x amygdalo-persica (adafuel), Tamarix gallica (tamarisk), Salix alba (white willow) and Platanus x hispanica (plane tree). The increase in plant growth three years after amendment application is evaluated with the aim to analyze the long term effect of the treated sewage sludges application on plant production. In general, the plants developed in the soils treated with ST sludge present the highest values of growth (diameter, height and width), which can be due to the faster supply of nitrogen from this material. However, the growth rate was higher in the CP treatment for the most of the species due to a continuous release of nutrients from the CP degradation. In this sense, the effect of CP treatment on plant production would be observed at the longer time than the ST one. Proceedings of the 26th European Biomass Conference and Exhibition, 14-17 May 2018, Copenhagen, Denmark, pp. 369-373

AbstractA large number of small- to medium-sized community ponds exist in most parts of the Terai region in Nepal. Such ponds could be a viable alternative for other forms of surface irrigation. But, with the lack of efficient management, many of these ponds remain underutilized. An effort was made to facilitate the rehabilitation of such a pond in a selected village of Rupandehi District in Western Terai region of Nepal. This paper aims to evaluate the changed water availability situation in post-monsoon seasons after the pond rehabilitation. The paper also evaluates the feasibility of such interventions especially focusing on the potential to provide additional water and improve agricultural productivity. Results showed small increases in quantifiable indicators such as water availability, cropping intensity, productivity and income. The new institutional setup improved water allocation, improved operation and maintenance, and increased social awareness among the people about the importance of underutilized water resources. The intervention has the potential to be replicated in similar contexts.

Abstract The Permian Basin in West Texas contains one of the thickest deposits of Permian rocks found anywhere in the world. The Embar-B lease located in southern Andrews County on the Central Basin Platform (a regional structural high in the Permian Basin) has been producing from the Leonardian Clearfork formation for over 70 years. The Clearfork formation is primarily a subtidal and intertidal carbonate rock characterized as moderate quality reservoir. Most Permian Basin fields have multiple stacked reservoirs with varying degrees of reservoir quality and there is typically a need in these maturing fields to increase reservoir contact. In 2009, a drilling campaign was launched in Embar-B with a focus on expanding the completion interval to include what was previously considered marginal pay in the deeper Wichita Albany formation. The Wichita Albany, also Leonardian in age, is composed mostly of marginal quality tidal flat rocks and is characterized by high fracture gradients and low permeability. These characteristics required an advancement in completion practices to achieve a successful stimulation. The combination of improved completions practices and an expanded target interval resulted in production double that of previous wells. This success has driven a need for an innovative development strategy and continued optimization of completion practices. Geomodeling, volumetrics, reservoir simulation, seismic attribute analysis and oil fingerprinting were all used for reservoir characterization and to determine an allocation method for commingled wells. This lead to the identification of several Clearfork/Wichita Albany locations with significant reserves potential. Re-evaluation of the completion strategy using a multidisciplinary approach indicated the need to reduce the number of perforation clusters, add a diversion mechanism, and develop multiple hydraulic fracturing designs based on reservoir quality and presence of natural fractures. Results from recent drilling programs have exceeded expectations bringing lease production up from 200 BOEPD in 2009 to a peak rate of 3153 BOEPD in 2015.

The possibility of using anaerobic digestate effluent (ADE) to replace freshwater and nutrients for bioethanol production was explored. The ethanol concentration yielded from ADE and post-centrifuged ADE supernatant was 79.60±1.75 g/L and 78.33±1.66 g/L, respectively, with a 24% dry mass (DM) of soft wheat. Ethanol production was enhanced in ADE by as much as 18% in comparison to the production in freshwater (66.61±0.28 g/L, p<0.01). Without yeast nutrients, ADE fermentation yielded an ethanol concentration of 81.10±2.87 g/L, which was significantly higher than that in freshwater fermentation (59.67±1.79 g/L). Analysis showed that ADE contained rich nitrogen, proteins and minerals. After one-step distillation, the ethanol concentration attained was 700.05±46.20 g/L in ADE as compared to 622.79±32.22 g/L in freshwater (p<0.05).

We investigated how a community of microbial decomposers adapted to a reference site responds to a sudden decrease in the water quality. For that, we assessed the activity and diversity of fungi and bacteria on decomposing leaves that were transplanted from a reference (E1) to a polluted site (E2), and results were compared to those from decomposing leaves either at E1 or E2. The two sites had contrasting concentrations of organic and inorganic nutrients and heavy metals in the stream water. At E2, leaf decomposition rates, fungal biomass, and sporulation were reduced, while bacterial biomass was stimulated. Fungal diversity was four times lower at the polluted site. The structure of fungal community on leaves decomposing at E2 significantly differed from that decomposing at E1, as indicated by the principal response curves analysis. Articulospora tetracladia, Anguillospora filiformis, and Lunulospora curvula were dominant species on leaves decomposing at E1 and were the most negatively affected by the transfer to the polluted site. The transfer of leaves colonized at the reference site to the polluted site reduced fungal diversity and sporulation but not fungal biomass and leaf decomposition. Overall, results suggest that the high diversity on leaves from the upstream site might have mitigated the impact of anthropogenic stress on microbial decomposition of leaves transplanted to the polluted site.