Nitrogen disposal

The result is that the amino groups can be dumped out as alanine (the transamination product of pyruvate). In the liver and kidney, alanine is transaminated to yield pyruvate and glutamate. As in the Cord cycle, the pyruvate is converted to glucose by the liver and is shipped out. The glutamate is fed into the urea cycle-nitrogen disposal system to get rid of the excess nitrogen. 

If rats are injected with a mixture of amino acids, there is a rapid increase in the liver content of glutamate. This is followed by an increase in acetylglutamate, a consequent increase in carbamoyl phosphate synthase activity and an increase in urea production. If excess amino acids are injected, the liver carbamoyl phosphate synthase becomes saturated with acetylglutamate and ammonia appears in the circulation. Thus regulation of carbamoyl phosphate synthase by N-acetylglutamate appears to be an important factor in the control of nitrogen disposal by the liver. 

The increasing number of atomic reactors used for power generation has been questioned from several environmental points of view. A modern atomic plant, as shown in Fig. 28-3, appears to be relatively pollution free compared to the more familiar fossil fuel-fired plant, which emits carbon monoxide and carbon dioxide, oxides of nitrogen and sulfur, hydrocarbons, and fly ash. However, waste and spent-fuel disposal problems may offset the apparent advantages. These problems (along with steam generator leaks) caused the plant shown in Fig. 28-3 to close permanently in 199T. 

Control of oxides of nitrogen can be accomplished by catalysts or ab-sorbants, but most control systems have concentrated on changing the combustion process to reduce the formation of NOj. Improved burners, change in burner location, staged combustion, and low-temperature combustion utilizing fluidized-bed systems are all currently in use. These combustion improvement systems do not generate waste products, so no disposal problems exist. 

They may require pH adjustment and settling. These effluents should preferably be recycled or reused. Spent catalysts are usually sent for regeneration or disposed of in a secure landfill. Air emissions should be monitored aimually, except for nitrate acid plants, where nitrogen oxides should be monitored continuously. 

Ultimate analysis-an analysis to determine the amounts of basic feed constituents. These constituents are moisture, oxygen, carbon, hydro- gen, sulfur, nitrogen, and ash. In addition, it is typical to determine chloride and other elements that may contribute to air emissions or ash- disposal problems. Once the ultimate analysis has been completed, Dulong s formula can be used to estimate the heating value of the sludge, Dulong s formula is ... 

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