Back Washing is a term used in water treatment to describe the process by which trapped or filtered contaminants in water during water treatment process are discharge or remove from the water treatment module. Figure 1 below shows a mini water treatment module, while figure 2 below shows a large pressure water treatment module( A Pressure Sand Filter Tank) Fig. 1. Treatment Module Fig. 2. Large Pressure Water Treatment Module Back Washing is a broad term which have different definition and meaning, but, in context to our lesson, it is best describe as above. Back Washing technically involved passing water in a reverse direction against the normal direction of water flow into and out of our water treatment module, during this reverse process the contaminants that were trapped such as particles, debris, flocs, e.t.c are removed or discharged from our water treatment module either into the environment or into a waste water treatment plant. Figure 3 shows the back wa...
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...