Total alkalinity

Scaling and corrosion are related phenomena. The properties of water influencing both are the calcium hardness, alkalinity, total dissolved solids, pH and temperature. Theoretically, the above conditions can be controlled so that the water is in equilibrium and neither corrosion nor scaling results. In practice, however, this equilibrium is difficult to achieve since it is a border condition, and a delicate balance must be maintained. 

Before proceeding, a few general comments will be helpful. In most cases at least one of the four carbonate system analytical quantities (total alkalinity, total CO2, carbon dioxide partial pressure, and pH) will be known. The equilibrium equations relating these quantities, along with those for water and calcite, will be used frequently in calculations. Also, in cases where calcite dissolution and... 

For example, lakes in drainage basins of easily weathered soils such as calcareous rocks (calcite, dolomite, gypsum, halite) generally have high values of pH, alkalinity, total dissolved solids, conductivity, and hardness. Such is the case for lakes located in cavities formed through the gradual dissolution of water-soluble rocks (solution or Karst lakes). On the other hand if the drainage basin is in an acidic rock basin (i.e., where silicates predominate and are difficult to weather), the water has an acidic pH, low alkalinity, and low total dissolved solids. 

Some of the traditional methods used for the characterization of bar soaps are moisture, free acid or free alkalinity, total soap, and chloride (salt). Moisture determinations are typically run by Karl Fischer titration. However, under certain circumstances, moisture can be measured gravimetric ally. The measure of free fatty acid or free alkalinity is typically done via a simple pH titration using phenophtha-lein or potentiometric end point. Total soap is generally done using an extraction/ gravimetric procedure the soap sample is acidified in an ethanol-water mixture, the fatty acids are extracted into a hydrocarbon solvent, and the amount of extracted... 

Example Temp = 140°F Ca hardness M alkalinity Total solids... 

Alkalinity, total and calcium hardness and salinity were the monitored quality parameters using standard titrimetric analytical methods according Romanian regulations as follows ... 

Table 1 presents the annual mean values for four quality parameters in Tabacarie lake water m alkalinity, total and calcium hardness and salinity. 

Alkaline phosphatase Alkalinity, total or Amylase Amyloglucosidase Aluminium... 

The following lake variables were determined (monthly samples from central lake sites) for pH, Secchi depth, temperature, alkalinity, total-P, chlorophyll-a, conductivity, Fe, Ca, hardness (= Ca+Mg concentration) and color. 

The solubility of elements in freshwater is limited and the solubility of calcium and magnesium carbonates are of particular importance in freshwaters. The solubility of carbonates is inversely proportional to the temperature of the water. In other words, as the water temperature increases, calcium and magnesium carbonates become less soluble. If the solubility decreases sufficiently, carbonates will precipitate and form a scale on the surfaces of the system. This scale can provide a protective barrier to prevent corrosion of the metallic elements in a system. Excessive scale deposits can interfere with water flow and heat transfer. The quality of the scale is dependent on the quantity of calcium that can precipitate as well as water flow and the chloride and sulfate content of the water. The tendency of water to precipitate a carbonate scale is estimated from corrosion indices such as the Langelier Saturation Index (LSI) and Caldwell-Lawrence calculations [6-8] which use calcium, alkalinity, total dissolved solids, temperature and pH properties of the water. Other indices, such as the Ryznar Index... 

Carbonate alkalinity = total alkalinity — A (milliequivalents/liter). 

Alkalinity It is distinguished in total and bicarbonate alkalinity. Total alkalinity is measured through titration to pH 3.7 and expresses the capacity of an anaerobic system to maintain the pH under acidification (Powell and Archer, 1989). However, total alkalinity increases as the VFA concentration increases. Therefore, the bicarbonate alkalinity, measured through titration to 5.75, can reflect the effective buffer capacity of the system. Various methods have been developed for the online measurement of the bicarbonate alkalinity (Table 10.3). 

---