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The remediation of metal contamination in estuarine and reduced sediments is another challenge for the electrokinetic process. Problems result from the complex chemical composition of saline reduced sediments. In the experiments described here copper was added into saline reduced sediments to simulate the natural situation. Two constant voltages were applied across the electrokinetic cell to investigate the effect of an increase in potential difference on the electrokinetic process. Acetic acid at pH 6 and 4 was also added to the cathode in separate experiments to enhance copper removal. The results from this study showed that in the unenhanced experiments most of copper remained in the soil and was unaffected by the electrokinetic process. At the end of unenhanced electrokinetic experiments, the copper concentration was found only to be slightly changed in the anode region. Up to 21% of the copper was found precipitated near the anode when the applied voltage was 10 V and this increased to 25% when the applied voltage was 7 V. In the enhanced electrokinetic experiments up to 98% of copper was removed from section 1 and precipitated again in sections 2 and 3. This indicates that a significant amount copper removal from the saline sediments may be achieved by the enhanced electrokinetic process.

Crown Copyright © 2014 Published by Elsevier B.V. All rights reserved. PRO and FO coupling with an RO membrane process is proposed to reduce the cost of seawater desalination and the potential for power generation. Three conceptual design configurations, PRO-RO, FO-RO and RO-PRO were evaluated here using standard seawater concentration and impaired water as the draw and the feed solutions respectively. The PRO-RO and RO-PRO designs were evaluated for power generation and seawater desalination while the FO-RO design was proposed for seawater desalination only. The impact of the draw and feed solutions' flow rate and the impaired water TDS on the performance of each design was estimated using pre-developed software. The simulation results showed that the performance of all designs was more sensitive to the increase in the flow rate of draw solution than to the flow rate of feed solution. Furthermore, all designs showed a decrease in membrane flux and recovery rate with increasing the TDS of feed water from 0.2 g/L to 10 g/L as a result of decreasing the net driving force across the membrane and the concentration polarization phenomenon. The FO-RO design produced the lowest RO permeate concentration followed by the PRO-RO and RO-PRO designs respectively. In terms of power generation, the RO-PRO design was more efficient than the PRO-RO design. The FO-RO design exhibited the lowest desalination power consumption followed by the PRO-RO and RO-PRO designs respectively. At 10 g/L feed concentration, the net power consumption in the FO-RO was 9.4% less than that in the PRO-RO which was in turn 5.3% less than that in the RO-PRO design. The estimated cost of the FO/PRO module in the PRO-RO design was 2.2 and 4.3 times higher than that in the FO-RO and RO-PRO designs respectively.

Dual stage PRO process was proposed for power generation. The present study evaluated two design configurations of the dual stage PRO process. The old dual stage PRO design was modified to enhance the process performance. In the new design, the entire seawater flow from the first stage goes to the second stage to increase the second stage membrane flux. Seawater salinities between 32 g/L and 45 g/L were tested to investigate the effect of draw solution TDS on the process performance. The results showed that PRO process performed better at higher seawater salinity. Furthermore, the performance of the new dual stage PRO design was higher than that of the old dual stage PRO process. Power density in the new dual stage PRO design was 17.4% higher than that in the old dual stage PRO design. Mainly, this was attributed to the higher membrane flux in the modified PRO design. It was also found that the specific power consumption of the new PRO design was about 8% less than that of the old PRO design. Finally, the results also showed that for a given plant capacity, the membrane elements required in the new PRO design were less than that in the old PRO design. As such, the proposed new design would be suggested for power generation for being more efficient and at cheaper cost.

The present study evaluated the performance of pressure retarded osmosis–reverse osmosis (PRO–RO) process for power generation and seawater desalination. Two pre-developed software were used separately to estimate the performance of forward osmosis (FO) and RO process. The draw and feed solutions in the FO process were seawater and low-quality water; i.e. wastewater effluent and brackish water. The simulation results showed that the FO performance increased with increasing seawater salinity and decreased with increasing feed water TDS. Increasing the feed and draw solution flow rate resulted in an increase in the FO performance especially when brackish water was used as a feed solution in the FO process. Power generation from the PRO process was found to increase with increasing the TDS of seawater and the flow rate of feed and draw solutions. The simulation results, however, showed that the PRO process was more sensitive to the increase in the seawater TDS than the flow rate of feed and draw solutions. For fresh water supply, the diluted seawater from the FO process was treated by RO membrane system. Up to 31% decrease in the desalination power consumption can be achieved by the PRO–RO process. It was also found that the increase in the draw solution flow rate resulted in an increase of the permeate concentration and power consumption. This issue should be considered in the operation of the PRO–RO system in order to reduce the overall treatment cost.

This paper presents an innovative approach for the design and development of Pipeline Inspection Gauge (PIG) which can inspect pipes from 26” up to 50” with a simple change of shirts using the latest technologies such as Electromagnetic Acoustic Transducer (EMAT) sensors as well as Remote Field Eddy Current (RFEC) sensors for oil pipes inspection, through the creation of a simulation tool capable of generating simulated images from pipeline using Inertial Navigation System (INS) for highest accuracy and precision inspection to protect the environment and equipment from any unexpected accident. There are several dynamo motors utilized to regenerate green efficient power from the flow of the medium inside the pipeline to elongate the distance of investigation by the mean of reduction of the number of individual pigging processes to save time and cost for companies. The INS uses accelerometers and gyroscopes of the type “Integrated Micro Electro-Mechanical Systems” (iMEMS), with these it can be carried out the mapping corresponding to the inspected pipes. Water hammer effect is another factor which has been considered during designing this pig. To avoid suck case to occur the design has been revised and several arms has been devised around the robot to maintain the speed and position of pig all the way through the pipeline.

A computational model for RO system design and performance prediction was developed in this study. The model was developed to estimate the performance parameters of RO in a multiple membrane elements pressure vessel. For simplicity the results of this study were compared with Reverse Osmosis System Analysis (ROSA) software which was assumed to have acceptable marginal errors. Two different feed water (NaCl) concentrations 35,000. mg/L and 38,000. mg/L were investigated in this study. In this paper, the recovery rate, salt rejection, feed pressure and permeate concentration of each RO element in the pressure vessel was compared with ROSA as shown in figures 2 to 5. The results from this study showed a very good agreement with ROSA up to 95%. Most of the previous studies were focused on studying the performance of a single RO membrane. This study, probably, the first to present a systematic procedure for estimating the performance of multiple RO elements in a pressure vessel. © 2012 Elsevier B.V.

The wide applications of Reverse Osmosis (RO) membranes in seawater desalination and various industrial processes have encouraged researchers and scientists to investigate the phenomena of water and salt diffusion through the membrane. Typically, the high pressure RO membrane vessel is loaded with membrane elements having the same flux and salt rejection rate. It has been conceived that when different types of RO elements are loaded into the pressure vessel in a special arrangement according to their permeability and salt rejection rate, this arrangement has the potential for reducing the energy consumption of the RO plant. A conceptual design is introduced here to describe this new idea. The effects of feed salinity and temperature were investigated in this paper using the ROSA Filmtec membrane design software. A two pass membrane treatment process was designed for desalting seawater at different salinities varied from 35000 ppm to 43000 ppm. The results showed a net energy saving from 2.5% to 3% (depending on the feed salinity) could be achieved. The effect of the feed temperature was also investigated and the new design was found to be more energy efficient. © 2011 WIT Press.