Like our teeth, placoid scales have an inner core of pulp (made up of connective tissues, blood vessels, and nerves), which is covered by a layer of dentine (hard calcareous material). This dentine is covered by enamel-like vitrodentine.Scales in bony fish grow as the fish gets larger, but placoid scales stop growing after they reach a certain size, and then more scales are added as the fish grows.his dentine is covered by enamel-like vitrodentine. Scales in bony fish grow as the fish gets larger, but placoid scales stop growing after they reach a certain size, and then more scales are added as the fish grows.
Wet air oxidation is a promising technology for the treatment of refractory organic pollutants in the effluent from various industries in view of high pollutant removal efficiency at mild conditions and environmental friendliness not involving any harmful chemical reagent.
treatment processes are typically used for the treatment of waste that has a high concentration of. biodegradable organic material. Anoxic and anaerobic processes do not require the input of. oxygen, which is typically an energy intensive process in aerobic systems. 5-1 Anoxic systems. Anoxic processes are typically used for the removal of nitrogen from wastewater. The process of. biological nitrogen removal is known as denitrification. Denitrification requires that nitrogen be. first converted to nitrate, which typically occurs in an aerobic treatment process such as a trickling.