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AbstractPrincipal Component Analysis (PCA) was used to evaluate groundwater quality data acquired in the pre-injection and injection periods for the Illinois Basin – Decatur Project (IBDP), a large-scale carbon capture and storage (CCS) project located in Decatur, Illinois, USA. For the pre-injection and injection periods three principal components explained 76.6% and 80.0% of the total data variance, respectively. Analysis of the pre-injection data set determined that highly positive loadings for total dissolved solids, chloride, bromide, sodium, magnesium, potassium, and electrical conductance designated the first component (PC1) as the salinity factor. High loadings for calcium, iron, and sulfate in component two (PC2) represents an oxidation-reduction component. The third component (PC3) represents groundwater acidity because of highly positive loading of pH. For the injection data set the variables contributed to the first component are bromide, sodium, total dissolved solids, chloride, electrical conductance, potassium, sulfate, iron, and calcium. Sulfate, magnesium, and calcium contribute to the second component and pH to the third component and represent salinity, dissolution, and acidity of groundwater. The results of the PC analysis indicate that water-rock interactions are the primary mechanism governing groundwater quality during both periods. The results of this analysis indicate that CO2 injection activities have not impacted the quality of the shallow groundwater in the project area.

AbstractA simple experiment for capillary sealed trap shows that leakage would occur only from the weakest point in the trap. As an extens ion of this concept, the sequestrated and accumulated CO2 in the structural high may happen to leak from the unexpected weak point near the top of sealing layer. On the other hand, if CO2 were sequestrated into the flank of tilted aquifer, CO2 in separate phas e would migrate upward within aquifer with no CO2 leakage into the sealing layer above and leaving some residual amount behind. According to this concept, the best location for sequestration of CO2 could be the flank of the structure rather than the top.

Abstract Uncertainties of cooling load may make cooling system oversized. Most of previous studies implement probabilistic-based uncertainty analysis, intending to achieve optimization and reliability simultaneously. However, how to reduce the load uncertainty has received little attention. This paper investigates the impact of water storage on the design of cooling system considering load uncertainty. Information entropy is used as a convergence index of load uncertainty and used to determine how many random simulations should to be performed. A cooling system configured with water storage (system B) and another system without water storage (system A as a comparation system) are investigated in this paper. In this paper, the configure of system A and system B are optimized respectively. The result shows that the capacity distribution of system A is consistent with the distribution of extreme loads. But, the capacity distribution of system B is more concentrated as the water storage can reshape the load curve. Water storage improves the flexibility of system B. Therefore, system B is more reliable and economical than system A.

AbstractA two-stage thermophilic fermentation for hydrogen and methane production from wastewater of cassava rice and corn starch at different concentration (5,10 and 15g/L) was studied. The hydrogen production from cassava starch at concentrations of 5g/L gave the highest hydrogen yield and followed by cassava starch at a concentration 10g/L, rice starch at concentrations of 15g/L. The hydrogen and methane yields from cassava starch processing wastewater by two-stage was 81.5 L H2 kgCOD-1 and 310.5 L CH4 kgCOD-1, respectively with total energy yield of 13363kJ kgCOD-1. Mixed hydrogen and methane (biohythane) production was 9.51 L biogas l-1 with containing of 55% CH4, 11% H2 and 34% CO2.

Abstract The main purpose of salinity gradient solar ponds (SGSPs) is to store the maximum possible solar thermal energy. A well-established salinity and temperature gradients are the main points to achieved optimum storage efficiency. In this work, a high-fidelity model is developed using computational fluid dynamics (CFD) to simulate the SGSP behavior under hot climate regions. The model is able to simulate the double convective effect by solving Navier-Stokes and energy equations, simultaneously. Brines with different salinities (i.e. 10%,15, and 25%) are used to investigate their role on the developed salinity/temperature gradients. Simulation results show the successful establishment of the three zones (i.e. upper convective, non-convective, and lower convective) with relatively stable salinity and temperature gradients. However, injecting the lower convective zone (or storage zone) with 10% saline brine results in preserving the highest storage temperature of around 79.2°C after flow time of six hours.

AbstractThis paper presents the experimental plans and designs as well as examples of predictive modeling of a pilot-scale CO2 injection experiment at the Heletz site (Israel). The overall objective of the experiment is to find optimal ways to characterize CO2 -relevant in-situ medium properties, including field-scale residual and dissolution trapping, to explore ways of characterizing heterogeneity through joint analysis of different types of data, and to detect leakage. The experiment will involve two wells, an injection well and a monitoring well. Prior to the actual CO2 injection, hydraulic, thermal and tracer tests will be carried out for standard site characterization. The actual CO2 injection experiments will include (i) a single well injection-withdrawal experiment, with the main objective to estimate in-situ residual trapping and (ii) a two-well injection-withdrawal test with injection of CO2 in a dipole mode (injection of CO2 in one well with simultaneous withdrawal of water in the monitoring well), with the objective to understand the CO2 transport in heterogeneous geology as well as the associated dissolution and residual trapping. Tracers will be introduced in both experiments to further aid in detecting the development of the phase composition during CO2 transport. Geophysical monitoring will also be implemented. By means of modeling, different experimental sequences and injection/withdrawal patterns have been analyzed, as have parameter uncertainties. The objectives have been to (i) evaluate key aspects of the experimental design, (ii) to identify key parameters affecting the fate of the CO2 and (iii) to evaluate the relationships between measurable quantities and parameters of interest.

Abstractwhatever the adoptod treatment system, the wastewater treatment is accompanied by production of large amounts of sludge which must be disposed. Several pathways exist lor the disposal of sewage sludge, but the choice must depend on the cost of installation, the result as an added value of the product and the possible impact of the chain retained on the environment To justify the choice of sludge recycling in agriculture, we will have to estimate the fertilizer value of sludge through the analysis of physico-chemica1 and microbiological parameters complying with regulations. Considering these parameters will detennine the worth of sludge,the environmental impact and precautions for use. For this purpose, we have to compare the sludge characteristics from three wastewater treatment plants (WIV) in the wilaya of Mascara, (west of Algeria), Mascara, Tizi and Ghriss. The results show that our overall sludge is rich in nutrients (N, P, K) but contains a hight concentrations in Nickel (Ni) of lIbout 8.6mg I kg prohably due to industrial waste. To enhance ille fertilizing power of the sludge in an agricultural field we recommend an additional treatment

Reverse electrodialysis (RED) is a technology to generate power from mixing waters with different salinity. The net power density (i.e. power per membrane area) is determined by 1) the membrane potential, 2) the ohmic resistance, 3) the resistance due to changing bulk concentrations, 4) the boundary layer resistance and 5) the power required to pump the feed water. Previous power density estimations often neglected the latter three terms. This paper provides a set of analytical equations to estimate the net power density obtainable from RED stacks with spacers and RED stacks with profiled membranes. With the current technology, the obtained maximum net power density is calculated at 2.7 W/m2. Higher power densities could be obtained by changing the cell design, in particular the membrane resistance and the cell length. Changing these parameters one and two orders of magnitude respectively, the calculated net power density is close to 20 W/m2