In certain parts of the world, communities’ sole source of water is water from deep wells, often many thousands of feet down. Almost half of the United States drinking water is groundwater. The Ogallala Aquifer is the sole source of water in central western part of the United States. An estimated 12 billion cubic meters of water is removed from the Ogallala Aquifer each year and 6 percent of the aquifer will dry up every 25 years, which leaves the residents and farmers of the Great Plains unsure about how long their water supply will last.
Water from groundwater sources is usually free of chemical and microbial contamination, but often become contaminated by disposal of liquid waste, mining operations, and agricultural runoff. By providing protection to the source, either through buffers from the reservoirs or by protecting the wellhead for the deep wells, water is available without much treatment.
There are less uncontaminated water supplies available due to increasing population and increased use of water. Water is treated before human consumption. Disinfection is an important step in the water treatment process to destroy pathogenic bacteria and other harmful agents. Most water is treated with chlorine, which is a very effective and economical method of treatment. An important advantage of using chlorine is that it has residual properties and continues to provide germ killing potential as the water travels from the distribution point to the end users. There are concerns about the formation of disinfection by-products from the reaction of the chlorine with humic substances in the water. Some of the bacteria and viruses we want to treat are becoming resistant to traditional means of disinfection.
Sanitation and Water Pollution
Sanitation is directly related to water quality and water pollution. The accepted approach to sanitation in the last century is to collect liquid waste in sewer systems, treat the wastewater in centralized treatment plants, and then discharging the effluent to surface water bodies. Although conventional sewer systems have significantly improved the public health situation for the communities, continued use adds pollution to our water supplies and reduces the purity of water needed for potable application later. This is becoming a worldwide problem not only for developing world with its inadequate sanitation, but also for developed world with its aging infrastructures that cannot meet the needs of increasing population.