A novel approach for SWRO desalination plants operation, comprising single pass boron removal and reuse of CO2 in the post treatment step

A new, energy-efficient approach for boron removal from SWRO plants

A cost effective method for improving the quality of inland desalinated brackish water destined for agricultural irrigation

Application of electrodeionization (EDI) for removal of boron and silica from reverse osmosis (RO) permeate of geothermal water

Treatment and reuse of produced water has become increasingly attractive. The complicated nature of produced water, however, and its variability make it challenging to reuse. Boron (B), a common component in produced water, is a concern when reusing produced water for hydraulic fracturing fluids. Excess boron in water can interfere with the timing of crosslinking reactions in hydraulic fracturing fluids, and premature crosslinking can increase friction pressure (horse power) when the fluid is being pumped. Lowering the boron concentration in produced water, therefore, will help to prevent or reduce formation damage and increase the stability of the hydraulic fracturing fluid. This paper presents a patent-pending and environmentally preferred process for boron and hardness removal from produced water. The traditional approach to boron removal has been to add chemicals (like activated alumina (Al2O3) or cerium oxide (CeO2)) or a chemically impregnated material (activated carbon) and clay as sorbents for boron removal from produced water, but these techniques have seen limited success. In these conventional approaches, sorption efficiency was affected by solution pH, initial boron concentration and other contaminants in the water. The method presented in this paper, however, is an environmentally preferred and simple process of adding liquid sodium silicate (Na2SiO3) to produced water for boron and hardness reduction. Efficient boron removal from more than 150 mg/L to less than 30 mg/L was achieved using this process, while at the same time, total hardness (as CaCO3) was reduced by more than 80%. While the waste solids that were created do contain high levels of calcium and magnesium silicate, it is proposed that they could be used for cementing material for oil industry applications thereby reducing the environmental impact of the process. Compared with other methods such as boron-selective resin, reverse osmosis (RO) or chemical sorption, this process exhibited better performance in the efficient removal of boron and hardness from produced water.

Enhanced boron removal by electricity generation in a microbial fuel cell

Comparative performance of FO-RO hybrid and two-pass SWRO desalination processes: Boron removal

Objectives : This article provides a comparative analysis of boron removal for brackish water reverse osmosis (BWRO), boron selective ion exchange (IX), or capacitive deionization (CDI) processes. Permeate of 1st-Pass RO process has to be post-treated for additional boron removal. Hence, we experimentally analyzed the performance of boron removal and specific energy consumption (SEC) of three aforementioned processes and investigated whether the processes are suitable for 2nd pass process of RO desalination.Methods : Raw feed water was prepared using NaCl and B(OH)3. Semi-pilot scale RO and IX systems (over 1 m3/hr capacity) and bench scale CDI system (over 2.5 L/min) were tested for performance comparison. Boron concentration was measured using Azomethine-H method for feed and product water. Energy consumption was monitored by using power quality analyzer.Results and Discussion : Each process has its own operating conditions. The RO process required high pH of feed water for high boron removal rate, the IX process was operated below breakthrough point considering adsorption capacity of boron selective resin, and the CDI process didn’t remove boron because chloride ion has higher ion selectivity for carbon electrode than boron. In terms of SEC, the pressure-driven RO process showed the highest SEC among three processes. The CDI process based on electrical adsorption of carbon electrode showed a considerable energy consumption as well. On the other hand, the IX process was operated at low energy consumption because its removal is just based on adsorption-desorption mechanism.Conclusions : The RO and CDI processes have received a lot of attention as leading and emerging technology while the IX process was regarded as a stubborn process because of regeneration of resin and its several segmentalized steps. However, we found that the IX process has a better performance for boron removal and energy consumption.

ABSTRACTThis study explored the feasibility of progressive freeze concentration in boron removal and its concentration in aqueous solution. The influence of three key parameters in progressive freeze concentration on boron removal and concentration, namely, the advance speed of the ice front, the circumferential velocity of the stirrer, and the initial boron concentration, are investigated by conducting batch experiments. The results show that the effectiveness of boron removal increases with a lower advance speed of the ice front, a higher circumferential velocity of the stirrer, and a lower initial boron concentration. For a model boron solution with an initial concentration of 100 mg/L, the boron concentration in the ice phase after progressive freeze concentration is below 1 mg/L when the advance speed of the ice front is lower than 1 cm/h and the circumferential velocity of the stirrer is higher than 0.12 m/s. In addition, the concentration of boron in the liquid phase occurs simultaneously with progressive freeze concentration. Furthermore, the results also suggest that this method can be applied to the purification and concentration of not only organic molecules but also inorganic ions.

Integrated pressure-driven membrane separation processes for the production of agricultural irrigation water from spent geothermal water

Seawater intake and pre-treatment/brine discharge — environmental issues

Objectives : The objective of this study is to investigate the potential for the removal of boron(B) from synthetic wastewater through chemical precipitation using microwave heating to identify the optimal conditions for the removal of boron.Methods : Synthetic wastewater was prepared using boric acid(H3BO3) and distilled water. The range of variables that exert an influence on boron removal included the initial pH 3-13, the calcium hydroxide(Ca(OH)2) dosage of 0.5-10 g per 30 mL(17–333 g/L), and the boron concentration of 100-1,500 mg/L. A face-centered design in response surface method was employed to identify the optimal conditions for boron removal in a continuous scale and to ascertain the interaction of the factors.Results and Discussion : In discontinuous conditions, the maximum removal efficiency was observed at initial pH 3, Ca(OH)2 of 2 g, and the boron concentration of 1,500 mg/L. As the pH value decreased, the removal of boron increased. The greatest removal efficiency was observed when the dosage of Ca(OH)2 was 2-5 g. It was also found that the higher the concentration of boron, the greater the removal efficiency. In the continuous scale, the optimal conditions for boron removal were identified as initial pH 3.3, the dosage of 6.2 g Ca(OH)2, and the boron concentration of 1,500 mg/L, with the removal efficiency of 93%. All independent variables exerted a statistically significant influence on chemical precipitation removal(p<0.05). In comparison to pH(p=0.047), boron concentration(p<0.001) and Ca(OH)2 dosage(p<0.001) demonstrated a more pronounced impact on boron removal. The interaction between boron concentration and Ca(OH)2 dosage was also identified as statistically significant(p<0.001).Conclusion : Chemical precipitation using microwave heating was effective in removal of boron from wastewater, and the optimal conditions in continuous scale through response surface analysis were initial pH 3.3, boron concentration 1,500 mg/L, and Ca(OH)2 dosage 6.2 g(207 g/L).

As water storage levels declined in Sydney, Australia, during 2003 and 2004, the New South Wales government imposed water restrictions and directed government agencies to conduct feasibility studies on new water supplies. Sydney Water commenced a desalination feasibility and planning study in 2005. By 2006, all planning and environmental approvals had been obtained. To confirm negligible impacts from operating a desalination plant, Sydney Water conducted an extensive marine monitoring program. Information required for the design phase was completed in mid-2007 and used to develop a blueprint that served as a proof of concept and hastened the procurement process. Information gathered included seawater-quality and current monitoring, physical modeling of diffusers, and ecotoxicity testing. Current baseline studies began in early 2007 and will continue until the plant is commissioned next year. The studies include water-salinity monitoring, reef habitat surveys, and organism recruitment studies. The studies will be repeated during the project's post-commissioning phase for three years. When collected, both datasets will be used to verify the environmental assessment's prediction of negligible effects on the marine environment resulting from desalination plant operation.

Corrosion experience data bank system for desalination and power plants (corex)

Impact of seawater desalination and wastewater treatment on water stress levels and greenhouse gas emissions: The case of Chile

Desalination of geothermal waters using a hybrid UF-RO process. Part I: Boron removal in pilot-scale tests