Total dissolved-solids

Purity = sugar content as percent of total dissolved solids content. 

From ref. 10 units are mg/L unless otherwise specified. Abbreviations IDS, total dissolved solids SS, suspended solids. 

Process data Sp. gr. of feed liquid = 1.0 TDS (total dissolved solids) in feed liquid = 4.0 wt % fresh water used for washing vacuum level = 18 in Hg final cake liquid content = 25 wt %. 

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. 

Environment Internal Untreated river water, pH 8.0-8.2, total dissolved solids 300 ppm, M alkalinity 100 ppm... 

For a quick estimate of total dissolved solids (TDS) in water one can run a conductivity measurement. The unit for the measurement is mhos/cm. An mho is the reciprocal of an ohm. The mho has been renamed the Sieman (S) by the International Standard Organization. Both mhos/cm and S/cm are accepted as correct terms. In water supplies (surface, well, etc.) conductivity will run about 10 S/cm or 1 iS/cm. 

McPherson, Lori, How Good Are Your Values for Total Dissolved. Solids Chemical Engineering Progress, November, 1995. 

Total dissolved solids (R) Legislation and controls Evaporation... 

TDS Total dissolved solids contained in solution in the cooling water system. 

Corrosive Liquid Chemical pH Constituent analysis Oil and grease content Total suspended solids Total dissolved solids... 

Treatment of brackish waters in the production of potable supplies has been the largest application of electrodialysis. Costs associated with electrodialysis processes depend on such factors as the total dissolved solids (TDS) in the feed, the level of removal of TDS (percent rejection), and the size of the plant. In brackish water treatment, operating costs for very large ED installations (on the order of millions of gallons a day) have been between 40 cents to 50 cents per 1,000 gallons for brackish feed waters, which compares favorably with RO costs. 

The general term for all water over 1,000 ppm (mg/L) total dissolved solids. 

TDS Total Dissolved Solids is commonly estimated from the electrical conductivity... 

Total Dissolved Solids (TDS)—Over 5,000 ppm can adversely affect thermal performance and may be detrimental to wood in the alternately wet/dry areas of the tower. 

Total dissolved solids (TDS) and silica (Si02) are normally given as such and do not require any conversion. 

The removal of each milligram of oxygen requires about 8 mg of sodium sulfite, so that the dose should be adjusted to suit the amount of oxygen introduced, which corresponds roughly to 80mg/l of cold make-up. A high level of condensate return therefore reduces the scavenger demand, and this is not only an economy in itself but can also mean a considerable reduction in the amount of total dissolved solids introduced into the boiler with the feedwater. 

TDS total dissolved solids determined by evaporating the water and weighing the residue. Units are mg/l. 

TDS Total dissolved solids, expressed as ppm (parts per million) or as mg/1 (milligrams per liter). Evaporate the water from a sample and the residue can be weighed. TSS Total suspended solids expressed in similar terms to TDS but representing a concentration of insoluble particles. 

For higher-pressure boilers demineralization is necessary to minimize total dissolved solids in the boiler. This water is normally carried in steel pipework, but if condensate is returned and the condensate has become contaminated (for example, with carbon dioxide or copper ions) more corrosion-resistant materials such as copper are required. Downstream of the boiler, steam pipework is usually steel with steel or stainless steel expansion bellows. 

An important assumption was that the solution was dilute (in this case natural water of approximately lOOp.p.m. total dissolved solids) since there are difficulties in applying mass transport equations for certain situations in concentrated electrolyte solution, where a knowledge of activities is uncertain and this can lead to large errors. 

At boiler pressures above about 85 bar, the tolerable level of total dissolved solids is so low that all the parameters specified are necessarily low in value. Several examples of recent specifications are given in Table 17.8 (feed) and 17.9 (boiler). 

Type Source Total dissolved solids cr soj- Ca Mg A Ikalinily pH Hardness (CaCO,) Free CO,... 

All steam-generating boilers operating at over 15 psig require at least daily blow down (blow off) to deconcentrate total dissolved solids... 

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. 

Provision of MU water for 100 to 150 psig FT boiler from a deep-well supply (large hotel complex, Caribbean). The water often contains iron and sulfur and is seasonally contaminated with salt water. Total dissolved solids (TDS) vary between 1,200 and 2,500 ppm. The process used is a. aeration for iron oxidation and... 

This formulation is designed as a single-drum treatment for boilers operating at up to 300 psig and with a total hardness (TH) in the FW of up to 30 ppm CaC03. Initial feed is 15 ppm product per 1 ppm TH (as CaC03) in the FW. Control is based on maintaining 200 to 300 ppm hydroxide (OH) alkalinity and a maximum of 3,000 ppm total dissolved solids (TDS) in the BW. 

Load swings, water levels, soot blowing, BW total dissolved solids, BW alkalinity and other factors all affect steam purity. 

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