Where Does Our Water Come From Word 2003

November 24, 2008

Where Does Our Water Come From? By Nathan Schumacher Water is essential to all plant, animal, and human life. People cannot live without potable water. Earlier civilizations faced many water born diseases in the way that they obtained water, but gradually evolved in ways to deliver clean potable disease free water. The first American water supply system was built in Boston in 1652. The supply was fed by springs and wells and piped to a wooden tank 12 feet square, where water was obtained by dipping it out with a bucket. This system supplied water to what was the entire city of Boston. We have come a long ways since then. In my eleven years of working as a plumber and a pipefitter I have found how much responsibility I have towards the public to keep them safe. I have studied the processes of water distribution for many years and made sure I knew how these systems needed to work so that I would not endanger the public in any way. Plumbers are not always called on to design water treatment facilities, but we are involved in their installation and maintenance. I will explain from my experience the principles of water treatment both municipal and private, and the principles of how a typical water distribution system works. When you use your water from the faucet to wash your hands it’s most likely that it will find its way back to the place where it came from. The same molecules may evaporate into clouds and as rain move to some other part of the planet. The cycle of evaporation, condensation into clouds and then precipitation through rain is essentially nature’s way of treating and purifying

water. Due to pollution it is almost impossible for nature to keep up in today’s world. Today almost all water that is used for human consumption has to be treated. The three principal sources of water used for human consumption are: rivers, lakes, and wells or aquifers. Wells are the most common source of individual or private water supplies in the case where water is not available by municipal means. According to The U.S. Environmental Protection Agency 15 percent of Americans rely on their own private drinking water supplies. Wells are most common because municipal water supply systems require miles of pipe to supply water from its source which may not always be practical. A well is typically close to its source on a person’s property which makes it more practical. There are four types of wells: driven wells, drilled wells, dug wells, and bored wells. Drilled wells are the most common. The recommended depth of a well is anywhere from 0 to 100 feet. In many cases well water is naturally purified through the natural filtration of passing through different layers of rock in the ground and does not need much treatment except when there is high pollution or high concentration of calcium and magnesium. Impurities in a source supply can be treated so as to yield potable water. Harmful impurities are: particles in suspension, minerals, gases, and pathogenic microorganisms. Impurities can be removed or neutralized by: sedimentation, filtration, aeration, and addition of chemicals. The first thing that is done when raw water is taken out of a river for potable use like in Cedar Rapids, Iowa is to remove debris like leaves, sticks, and other matter. The water is pumped from the river through pipes to a basin where the debris is allowed to settle. This is called sedimentation. When an underground well source is used like in Iowa City, Iowa this process called sedimentation is not necessary because the water is taken from aquifers in the ground

which are protected from debris. These aquifers are underground caverns which are mostly rock or loose rock that holds water which through time water had naturally filtered through to this point. When the water is clear of larger sediment chlorine it is then added to kill any bacteria or viruses. This chlorine is similar to the bleach you may use to clean your cloths. It is then sent through another tank in a process called coagulation similar to the one to remove larger debris except now it is put through a process to remove tiny particles. A chemical called alum is added to the water in a tank which makes these particles heavy and they settle to the bottom of the tank. The sediment free water from the top of the tank flows through pipes or canals to a process to remove trapped gasses by either aeration or degasification. An aerator is a tank with many steps or grates made of wood in which water flows down by gravity and a blower pushes the gases out to the atmosphere in this open tank. Gases may also be removed by adding chlorine or another oxidizing agent which changes the gas to a solid and then removed through a filter. Chlorine is added again to kill any remaining bacteria. The water is sometimes sent through a sand filter to remove any more particles and this completes the cycle for producing water of potable drinking quality. There are many different processes to make water taste better, but are not often used in municipal applications because of the high expense. Water is sometimes run through charcoal filters, sand and gravel filters, and water softeners which are usually private installations in homes at the point of use. After water goes through all of the processes needed for human consumption it needs to get to your house, right? Usually water is pumped through a system of pipes from the water plant to

different water towers. Water towers are normally used to keep a constant pressure of water. If water was only pumped it would not always maintain the pressure needed when demand is higher. This system of water being pumped to the water tower also keeps the pumps from constantly running all the time which makes them last longer. Often water towers are kept at a specific level of water to maintain head pressure or gravity pressure. A float switch is inside the tank of the water tower to turn the pumps on and off when water is needed. In some instances only pumps are used to convey water, but this is not a common practice. So, as most of us know, there are pipes running through the ground from the water plant called mains. These are bigger pipes that carry water into the cities or towns to supply your homes and businesses with water. Smaller size pipes branch off of these mains called service lines to your home and are usually kept five feet below the frost level in Iowa to prevent freezing. In areas that are not subject to freezing temperatures water pipes are only buried inches under the ground and sometimes not buried at all. After your water is used it flows through your building drain to a sewer and then to a sewage treatment plant. In some cases the sewage treated water goes right to the water plant to be treated for potable use again. Although in most instances after sewage water is treated it is dumped back into streams and rivers to be circulated through the natural process and possibly back your way. The waste that is removed at the sewage treatment plant is collected in a solid bulk form and normally transported to the city dump by truck. If you did not know where your water came from I hope you have a better idea. Water is our most valuable resource. We need water to live and we need to protect it. The nation’s best places to get water are our underground aquifers and they are starting to dry up. Eventually the

processing of water will become more needed. We often hear we should try to conserve water as much as possible. It is no joke. We need to stop wasting water and polluting or we may very well see a shortage in our water supplies which may not be too far away.