Sewage Treatment
Information
Sewage treatment is a necessary and important aspect of industrialized and pre-industrial societies. Civilizations have long understood the importance of disposing of used water in a separate system from that of fresh water. This prevents diseases and helps keep the ecosystem functioning. The process to separate good water from sewage is timely and expensive; however, very few advances have been made for alternatives to the system.
Significance
Sewage needs to be treated to ensure that the water used by people is distributed back into the ecosystem with as little environmental impact as possible. Sewage can include any water that is used by humans for disposal or through various other processes such as radiation cooling. This water becomes contaminated with waste, including objects, excrement and food products. The sewage cannot be sent directly back into the water supply, or contamination of plants and animals and eventually humans would take place. All solids must be removed through physical screening or sedimentation. In addition, all soluble and fine suspended organic pollutants must be dispelled through a biological oxidation process.
Features
A sewage treatment facility uses an intricate system to remove all large objects and pollutants from the waste water.
The first step in this process is the removal of large objects such as cans, tampons and foods. The sewage treatment facility uses a large grating machine that circles around a vat of sewage, collecting the objects. These objects are later disposed in a landfill. The sewage then passes through a sedimentation pump in which oils are allowed to float and sludge is allowed to sink. The machine skims off these elements for further disposal.
The remaining sewage is then treated biologically using various types of bacteria that consume or trap the remaining particles. Through a series of holding facilities, the sewage is put through different types of biological processing. By the time it is done, the vast majority of non-water elements are removed.
The tertiary step of sewage treatment is to let the water sit in a large basin or manmade lagoon. This allows further aeration and natural cleaning of the water. The clean water is then released back into the water supply.
This process, at each level, creates a byproduct called sludge. This sludge can be further processed into fertilizer and methane gas for burning.
Benefits
By cycling used water through a process, humans can ensure that the drinking water and water in lakes and rivers is clean. Before proper sewage treatment took place, many cities would just pump their water into lakes and streams. These water beds would soon become contaminated, killing vast numbers of wildlife and plants. It also had negative effects on humans, such as diseases and skin irritation.
Modern facilities ensure that the continued use of water resources is possible for an industrialized nation. They are also very important for developing countries to stop the spread of diseases.
Effects
The introduction of sewage plants across the United States also had negative effects, most notably, energy consumption. The process to treat sewage is very inefficient and can result in some of the highest energy consumption concerns for a community. According to the U.S. Department of Energy, sewage treatment plants account for 3 percent of all energy consumption in the U.S. For example, for each gallon of water that is treated, a compact fluorescent light bulb could run for nearly 12 minutes.
Additional problems have arisen during the late 1990s and the early part of the 21st century. The amount of drugs and medicines being flushed into the water system continues to increase. Small quantities of antibiotics, sex hormones and anti-seizure drugs have all been isolated, according to the Associated Press. Modern sewage treatment plants are ill-equipped to handle the removal of drugs from the system.
Potential
Many communities are turning to on-site sewage treatment opportunities to limit the electricity needs of the main sewage plant, as well as keep the water healthier in the long run. Most of these options include a septic tank that is installed with various filters and aeration systems. These septic tanks need to be emptied by the sewage company; however, the water they receive is further along the cleaning path than previous sewer systems.
This has been shown by the Department of Energy to cut down on the costs of sewage treatment by up to 30 percent.
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