Dissolved solids, produced water

Lime, Ca(OH)2 Very efiective commonly used may not add dissolved solids to water Very pH dependent produces large qty. of sludge overdose can result in poor effluent quahty... 

Potable Water RO and NF both play a major role in providing potable water, defined either by the WHO criterion of <1000 ppm total dissolved solids (TDS) or the U.S. EPA limit of 500 ppm TDS. RO is most prominent in the Middle East and on islands where potable-water demand has outstripped natural supply. A plant awaiting startup at Al Jubail, Saudi Arabia produces over 1 mVs of fresh water (see Table 22-17). Small units are found on ships and boats. Seawater RO competes with multistage flash distillation (MSF) and multieffect distillation (MED) (see Sec. 13 Distillation ). It is too expensive to compete with conventional civil supply (canals, pipelines, w ls) in most locations. Low-pressure RO and NF compete with electrodialysis for the desalination of brackish water. The processes overlap economically, but they are sufficiently different so that the requirements of the application often favor one over the others. 

In recapping, DAF is the process of removing suspended solids, oils and other contaminants via the use of bubble flotation. Air is dissolved into the water, then mixed with the wastestream and released from solution while in intimate contact with the contaminants. Air bubbles form, saturated with air, mix with the wastewater influent and are injected into the DAF separation chamber. The dissolved air then comes out of solution, producing literally millions of microscopic bubbles. These bubbles attach themselves to the particulate matter and float then to the surface where they are mechanically skimmed and removed from the tank. Most systems are versatile enough to remove not only finely divided suspended solids, but fats, oils and grease (FOG). Typical wastes handled include various suspended... 

Demineralized water is water from which all the minerals have been removed by ion-eNchange. It is used where pure water is needed for a process and as boiler feed water. Mixed and multiple-bed ion-exehange units are used for this purpose, one resin converting the cations to hydrogen and the other removing the acid radicals. Water can be produced that has less than I ppm of dissolved solids. 

Water purification and recycling is now a major industry.The method of treatment depends on the source of the water, the use envisaged and the volume required. Luckily the human body is very tolerant to changes in the composition of drinking water, and in many communities this may contain 0.5 gl or more of dissolved solids (Table 14.7). Prior treatment may consist of coagulation (by addition of alum or chlorinated FeS04 to produce floes of Al(OH)3 or Fe(OH)3), filtration, softening (removal of... 

The initial cause of many waterside problems is the various dissolved solids, gases, and other impurities introduced into the boiler from the MU water, the atmosphere, and associated industrial or other processes. These impurities may produce scale and also lead to corrosion and other operational problems. 

Although the presence of hardness is reported as calcium carbonate, in reality, for most water supplies the most common major contributors to total dissolved solids are calcium and magnesium bicarbonates. These dissolved solids most readily produce crystalline scales and thus predominantly contribute to boiler system deposits unless removed by some form of pre-boiler, external treatment process. 

Many of the cold packs sold in stores use this endothermic process. A cold pack usually contains a flimsy plastic bag of solid ammonium nitrate inside a larger package filled with water. When punched, the inner bag ruptures. This releases the ammonium nitrate, which dissolves and produces a chilled pack to relieve pain and swelling in aching joints. 

Read the label of the crystal drain cleaner package. Understand that the compound is solid sodium hydroxide that contains aluminum. When the material is added to water, sodium hydroxide dissolves rapidly, producing heat. Aluminum reacts with water in the basic solution to produce Al(OH)4 ions and hydrogen gas. Is aluminum oxidized or reduced in the reaction Is hydrogen oxidized or reduced in the reaction Explain your answers. 

The concentrations of seawater and brackish water can vary significantly, and as such there is a difference between the concentrate produced from seawater desalination plants and brackish water desahnation plants. Seawater typically has a level of total dissolved solids (TDS) between 33,000-37,000 mg/L. The average major ion concentration of seawater is shown in Table 2.1 along with water from the Mediterranean Sea, and water from Wonthaggi off the southern coast of Australia. Seawater sahnity increases in areas where water evaporates or freezes, and it decreases due to rain, river runoff, and melting ice. The areas of greatest salinity occur and latitudes of 30° N and S where there are high evaporation rates. 

The major ions have two main escape routes from the ocean (1) incorporation into sediments or pore water and (2) ejection into the atmosphere as seasalt spray. This spray is caused by bursting bubbles that produce small particles, called aerosols, that range in diameter from 0.1 to 1000 pm. The annual production rate of seasalt aerosols is large, on the order of 5 x lO kg/y, but virtually all of it is quickly returned when the spray fells back onto the sea surfece. A small fraction (about 1%) is deposited on the coastal portions of land masses and carried back into the ocean by river runoff. As shown in Table 21.6, seasalts represent a significant fraction of dissolved solids in river runoff, especially for sodium and chloride. Due to the short timescale of this process, seasalt aerosol losses and inputs are considered by geochemists to be a short circuit in the crustal-ocean-atmosphere fectory. The solutes transported by this process are collectively referred to as the cyclic salts. ... 

A "Permasep" permeator reverse osmosis (RO) installation, capable of producing 1500 cubic meters of product water per day, was successfully operated for six months with RO feed water drawn from cUi estuary cuid having 1200 to 1400 mg/H total dissolved solids (TDS). 

Disposal of brine in subsurface wells is probably the most widely used control method, especially in the western and southern oil and gas producing states [23]. For this to be an effective disposal option, two conditions must be met the natural aquifer must be naturally saline and must not leak to freshwater aquifers, and the reinjection pressure must not exceed the fracture pressure of the formation [9]. Produced water is usually pretreated to prevent equipment from being corroded and to prevent plugging of the sand at the base of the well. Pretreatment may include the removal of oils and floating material, suspended solids, biological growth, dissolved gases, precipitable ions, acidity, or alkalinity [27]. A typical system is shown in Fig. 12. 

The injected fluids usually have a chemical composition that is different from that of the in situ reservoir fluids, particularly when steam has been separated from the liquid phase and only the separated water is re-injected. The steam phase will be enriched in non-condensable gases, whereas the separated water has a higher concentration of dissolved solids, but a lower gas content. Changes in the chemistry of the produced fluids are to be expected in all fields where re-injection of separated water has been applied. When the same water is recycled, successive steam loss will increase its salinity, which may in turn lead to scaling problems (see Amorsson, 2004). 

Hexammino-chromic Iodide, [Cr(NII3)G]I3, is also formed by the decomposition of the nitrate. A solution of hexammino-chromic nitrate is shaken with solid potassium iodide, the precipitate formed is washed with hydriodic acid, dissolved in cold water, and repreeipitated with dilute acid. It separates in yellow rhombic plates and is sparingly soluble in cold water. On warming with hydriodic acid iodo-pent-ammino-iodide is not produced.1... 

Usually the gas is water-quenched to remove solids and tars. Ammonia, HCN, H2S dissolve in the water and high -content gas at high pressure may produce some formic acid. Purification of quench water contributes secondary Claus feeds, as will be seen. 

Calcium chloride dissolves to produce three ions, whereas sodium chloride dissolves to produce only two. The greater number of ions generated by calcium chloride is more effective at decreasing the number of water molecules entering the solid phase. 

Most oil-field waters contain sufficient dissolved solids to create favorable flotation bubble sizes. Some steamflood produced waters contain only 2,000-5,000 ppm dissolved solids, and would tend to generate large, less effective bubbles. 

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