Ultra Violet Lamp We'll look at both artificial and natural radiations, which needs electricity and lamps to generate the energy, and natural radiation, making use of the sun's energy for solar disinfection. Ultraviolet radiation is one type of energy along the electromagnetic spectrum, where different kinds of radiation are defined by their wavelength. Ultraviolet has wavelengths in the 100 to 400 nano meter range, whereas the visible light is in the 400 to 700 nano meter range. If we zoom in on this range we can define some subcategories. 1.The lowest wavelength we call vacuum UV. It only exists in the vacuum, but then we have UV-C, or deep ultraviolet, where the germicidal peak at 260 nano meters is found. Then you've got UV-B and UV-A shading into the visible light spectrum from 400-700 nano meters. Now in order to describe the efficacy of UV light against different types of pathogens, weneeds to first define the dose. And just as for heat, it's importan...
Iron is one of the major secondary contaminant in both domestic and industrial water supply. Iron have caused water industries several billions of dollars . Iron is the second most abundant metal in the earth's crust behind Aluminum(8%), of which iron accounts for about 5%. Elemental iron is rarely found in nature, as the iron ions Fe2+ and Fe3+ readily combine with oxygen- and sulfur-containing compounds to form oxides, hydroxides, carbonates, and sulfides. As rain fall, rain water infiltrates the soil and underlying geologic formations and dissolves iron, causing it to seep into aquifers that serve as sources of groundwater for wells. In surface water, such as rivers and lakes, dissolved iron is hardly ever found, because it readily reacts with oxygen, forms insoluble compounds and sinks out into the bottom of the water body. Iron is seldom found at concentrations greater than 10 milligrams per liter (mg/L) or 10 parts per million. The iron that seep into the sources of g...