Brine permeate

The high-calcium chloride brine of Bristol Lake has been continuously recovered on a commercial basis since 1910 (Jachens and Howard, 1992). The brine permeates the uppermost 9.75 m section of the playa sediments, and appears to be present throughout the entire lake. However, the permeability of the sediments... 

Electrodialysis. Electro dialysis processes transfer ions of dissolved salts across membranes, leaving purified water behind. Ion movement is induced by direct current electrical fields. A negative electrode (cathode) attracts cations, and a positive electrode (anode) attracts anions. Systems are compartmentalized in stacks by alternating cation and anion transfer membranes. Alternating compartments carry concentrated brine and purified permeate. Typically, 40—60% of dissolved ions are removed or rejected. Further improvement in water quaUty is obtained by staging (operation of stacks in series). ED processes do not remove particulate contaminants or weakly ionized contaminants, such as siUca. 

Osmotic Pinch Ejfect Feed is pumped into the membrane train, and as it flows through the membrane array, sensible pressure is lost due to fric tion effects. Simultaneously, as water permeates, leaving salts behind, osmotic pressure increases. There is no known practical alternative to having the lowest pressure and the highest salt concentration occur simultaneously at the exit of the train, the point where AP — AH is minimized. This point is known as the osmotic pinch, and it is the point backward from which hydrauhe design takes place. A corollary factor is that the permeate produced at the pinch is of the lowest quality anywhere in the array. Commonly, this permeate is below the required quahty, so the usual prac tice is to design around average-permeate quality, not incremental quahty. A I MPa overpressure at the pinch is preferred, but the minimum brine pressure tolerable is 1.1 times H. 

Concentrate recycle RO plants allow some of the brine reject water to recycle back through the plant, which improves the permeate recovery rate. (The reduced flow of brine reject water does of course have a proportionally higher TDS level.) Various types of high pressure, corrosion-resistant pumps are used, including multistage, centrifugal and plunger pumps, each with their own benefits and area of application. 

In the other three membrane processes, for example, in RO, a membrane is mounted in an apparatus so that a two-section compartment is formed. Contaminated water is pressurized and circulated through the high-pressure-solution compartment. Water permeates to the low-pressure side and is removed. The concentrated brine is removed separately. 

Rona and Schmuckler [410] used gel permeation chromatography to separate lithium from Dead Sea brine. The elements emerged from the column in the order potassium, sodium, lithium, magnesium, and calcium and it was possible to separate a lithium-rich fraction also containing some potassium and sodium but no calcium and magnesium. 

Carbon dioxide permeates the membranes at least as readily as does chlorine. This fact will produce a significant increase in CO2 concentration in a recycle system. For best results at highest chlorine recovery, it will pay to keep the CO2 concentration in the membrane feed-gas low. This can be accomplished in most plants by acidification of cell-feed brine. Acidification is highly recommended in any case when a very high degree of chlorine recovery is required, whether by... 

In the example shown in Fig. 11.3, a feed-stream containing a sodium sulphate concentration of 20 g l-1, with a flow rate of 3.43 m3 h 1, is split into two streams by the filter, namely a concentrate stream of 0.8 m3 h 1, with 83 g 1 1 of sodium sulphate and a permeate stream of 2.63 m3 h-1, with a sodium sulphate concentration of 0.82 g l-1. The permeate stream is returned to the brine saturators and the concentrate stream is sent to effluent. 

The trials, which were carried out in 1997 and 1998, have provided the data and understanding of the relationships between permeate flow and inlet brine velocity for different operating pressures. The graph in Fig. 11.4 shows that the brine permeability, when kept at constant inlet velocity through a standard membrane, is quite predictable for a known concentration of sulphate in the brine. The upper and lower... 

The majority of the discharge from a desalination processes is concentrated brine from the membrane process, and this may contain quantities of treatment chemicals used. Treatment of water is necessary in all desalination plans for variety of reasons feed water treatment, membrane protection, membrane cleaning, permeate treatment and concentrate treatment prior to discharge. Although non-chemical treatment is possible, chemical treatment is widely practiced. 

The first success at UCLA was reported in 1958 (, 2). A flat plastic film, supported by a porous plate, was useJ. The film was pressurized by a salt solution such that water permeation could occur by virtue of the pressure drop across the film and a more concentrated brine could be left behind. This was... 

A soln of 4-nitrophenyl carbamate 28 (45 mg, 0.068 mmol), TFA - H-Leu-Leu-OMe (31 mg, 0.083 mmol), and DMAP (13 mg, 0.11 mmol) in CHC13 (5mL) was stirred for 4d under argon. The mixture was washed with 1M HC1, aq NaHC03, brine, and dried (MgS04). The soln was filtered and concentrated to give a residue, which was purified by gel-permeation chromatography to afford the urethane peptide 29 as white crystals yield 31 mg (58%) mp 79-81 °C. UV Xmax (MeOH) 309nm (e 12400). 

Scale is caused by precipitation of dissolved metal salts in the feed water on the membrane surface. As salt-free water is removed in the permeate, the concentration of ions in the feed increases until at some point the solubility limit is exceeded. The salt then precipitates on the membrane surface as scale. The proclivity of a particular feed water to produce scale can be determined by performing an analysis of the feed water and calculating the expected concentration factor in the brine. The ratio of the product water flow rate to feed water flow rate is called the recovery rate, which is equivalent to the term stage-cut used in gas separation. 

The RO design screen shown in Figure 10.10 appears when the calculation is completed. All outputs are populated including performance of each stage of the system as well as the permeate quality and concentrate ("brine") pressure. 

The treatment of bilge water and emulsions resembles that of the treatment of oil field brines and produced water. Chen et al. [25], using ferric chloride and other chemicals to enhance the performance of Membralox 0.2, 0.5 and 0.8 pm membranes, describe permeate fluxes between 1400 and 34001/m h. Without pretreatment however severe fouling occurred as well as break-through of oil. Zaidi et al. [26] report about the continuation of this work. They quote fluxes between 800 and 12001/m h, but also mention substantial lower fluxes in long term pilot tests using 0.8 pm membranes. In addition they indicate a drop in permeate flux caused by conditions of low pH, the presence of sea water, corrosion inhibitor, oil slugs or flow variations. 

When a constant voltage is applied to the electrodes, all cations migrate towards the cathode, and all anions migrate towards the anode. The cations can pass through the cation-permeable membrane, but they cannot permeate the anion-permeable membrane. The counter argument applies to anions. Alternate compartments contain ionic concentrations that are greater or less than the feed solution. These compartments are then combined to create the brine (waste) stream and the purified water stream. 

This system is represented by a closed basin, made of impermeable rocks and filled in the past by a saline alkaline lake. Water in this case could not permeate downwards but only evaporate, so the deposit develops horizontally, instead of vertically as in the previous occurrence. Here pH and salinity in the fluids tend to increase, giving rise to brines, c.g., basic, alkali-rich solutions. Concentric zones of authigenic minerals are so formed, from an outer and upper ring of little altered glass and clay minerals, to zeolites, analcime and a finally alkali-feldspars. A good example for this type of occurrence is Lake Tecopa, California, where the zeolitic ring is constituted by phillipsitc, clinoptilolite and erionite, followed by the central feldspar zone [36]. 

RO is used to treat 1.31 m3/s of seawater at 293 K containing 3.5 wt% dissolved solids to produce 0.44 m3/s of potable water with 500 ppm of dissolved solids. The feed-side pressure is 138 bar, while the permeate pressure is 3.4 bar. A single stage of spiral-wound membrane is used that approximates crossflow. If the total membrane area is 0.10 km2, estimate the permeance for water and the salt rejection. Assume that the densities of the seawater and of the brine are approximately equal to the density of pure water. 

The resulting dates may be systematically in error in cases where the measured Sr/ Sr ratio of the mineral has about the same magnitude as the initial Sr/ Sr ratio. In addition, radiogenic Sr may escape from Rb-bearing minerals as a result of slow cooling or by subsequent contact metamorphism or by isotope exchange with Sr in brines that may permeate the rocks. The loss of radiogenic Sr by these or other processes lowers Rb-Sr mineral dates and causes them to underestimate the crystallization age of the host rock. 

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