Abstract: A membrane filtration process includes pretreating an influent solution to remove suspended solids, to produce a pretreated solution. pH of the pretreated solution is adjusted to at least 8.3 or lower by injecting CO2 into the pretreated solution, to produce a conditioned solution. Injecting CO2 also serves to supplement bicarbonate in the conditioned solution. The conditioned solution is flowed through a membrane filtration unit, to produce a permeate solution and a retentate solution. The membrane filtration unit comprises reverse osmosis membranes or nanofiltration membranes, or both. The retentate solution is then treated to cause precipitation, to produce a supernatant solution and a reject solution. At least a portion of the supernatant solution is recirculated by combining it with the influent solution prior to the step of pretreating.

Abstract: A membrane filtration process includes pretreating an influent solution to remove suspended solids, to produce a pretreated solution. pH of the pretreated solution is adjusted to at least 8.3 or lower by injecting CO2 into the pretreated solution, to produce a conditioned solution. Injecting CO2 also serves to supplement bicarbonate in the conditioned solution. The conditioned solution is flowed through a membrane filtration unit, to produce a permeate solution and a retentate solution. The membrane filtration unit comprises reverse osmosis membranes or nanofiltration membranes, or both. The retentate solution is then treated to cause precipitation, to produce a supernatant solution and a reject solution. At least a portion of the supernatant solution is recirculated by combining it with the influent solution prior to the step of pretreating.

Abstract: A corrosion detection apparatus is provided. The corrosion detection apparatus is capable of detecting corrosion on a surface of a pipe or a vessel where the surface contacts a fluid that is corrosive to the surface. The corrosion detection apparatus includes a corrodible element having a contact surface; at least two electrodes that are in electrical communication with each other through a segment of the corrodible element; and a detector in communication with the at least two electrodes. The detector detects a characteristic impedance value from the at least two electrodes through the corrodible element segment.

Abstract: The invention relates generally to corrosion sensors having one or more linear reactive impedance corrosion element capable of detecting both general and local corrosions, and to methods for detection same.