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Physical Water Treatment Effects on Evaporation Rates, Hardness, and Microbial Life

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The rising need for water reuse in the Southwest United States has increased awareness of the quality of wastewater. This need is caused by an increased population having basic water

The rising need for water reuse in the Southwest United States has increased awareness of the quality of wastewater. This need is caused by an increased population having basic water needs; inefficient water use, such as overwatering lawns and leaking pipes; and recent drought conditions all over the southwestern US. Reclaimed water is a possible solution. It's used for a variety of non-potable, or non-drinkable, reasons. These uses include: cooling power plants, concrete mixing, artificial lakes, and irrigation for public parks and golf courts. Cooling power plants utilizes roughly 41% of the total water consumed by the United States, which makes it the highest user of water in the US. The attention is turned to optimizing mechanical processes and reducing the amount of water consumed. Wet-recirculating systems reuse cooling water in a second cycle rather than discharging it immediately. Cooling towers are commonly used to expose water to ambient air. As the water evaporates, more water is withdrawn while the rest continues to circulate. These systems have much lower water withdrawals than once-through systems, but have higher water consumption. The cooling towers in wet-recirculating plants and other warm machinery have two major limitations: evaporation of pumped water and scale formation in the components. Cooling towers circulate water, and only draw as it evaporates, which conserves water. The scale formation in the components is due to the hardness of the water. Scale occurs when hard water evaporates and forms solid calcium carbonate. This formation can lead to reduced flow or even clogging in pipes, fouling of components or pipes, and reduced cooling efficiency. Another concern from the public over the use of reclaimed water is the possibility of there being fecal contamination. This fear stems from the stigma associated with drinking water that essentially came from the toilet. An emerging technology, in order to address these three issues, is the use of an electromagnetic device. The wires have a current flowing through which induces a magnetic field perpendicular to the direction of the flow, while the electrical field is proportional to the flow velocity. In other words, the magnetic and electrical fields will create an effect that will concentrate cations at the center of the pipe and anions at the wall of the pipe or the other way depending on the direction of the flow. Reversing the field will then cause the cations and anions to move toward one another and increase the collision frequency and energy. The purpose of these experiments is to test the effects of the electromagnetic device on the aforementioned topics. There are three tests that were performed, a surface tension test, a hardness test, and a microbial test. The surface tension test focused on the angle of a water droplet until it burst. The angle would theoretically decrease as the bond between water molecules increased due to the device. The results of this test shows a lower angle for the treated water but a higher angle for the untreated one. This means the device had an effect on the surface tension of the water. Hard water is caused by calcium and magnesium ions in the water. These ions are dissolved in the water as it travels past soil and rocks. The purpose of this test is to measure the free calcium ion amount in the water. If the free calcium number lowers, then it can be assumed it collided with the carbonate and formed calcium carbonate. This calcium carbonate causes a reduction in hardness in the water. The result of the test showed no correlation between ion concentrations in the treated/untreated system. The e. coli test focused on testing the effects of an electromagnetic device on inhibiting fecal contamination in water/wastewater at a treatment facility. In order to detect fecal contamination, we test for bacteria known as fecal coliforms, more specifically e. coli. The test involved spiking the system with bacteria and testing its concentrations after time had passed.The e. coli results showed no trend in the inactivation of the bacteria. In conclusion, the device had varying results, but multiple steps can be taken in the future in order to continue research.

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Date Created
  • 2014-12