Wastewater Treatment Essay, Research Paper
The world today is faced with a lot of different waste problems. One major problem is how to get rid of the waste safely so that it does not disrupted the environment or hurt people or animals. The major problem for the United States is waste water, the amount, and the cost of treatment and disposal.
The United States treats over 1 billion tons of waste a year. How do we treat that much waste.
One way it to send the waste water into a treatment plant ran by the state or county. The water contains solid particles, which mixed with the untreated water is called sludge. The sludge contains solid particles, like wood, dead animals, and trash that could cause problems later on, so they filter out all this stuff and send it to a land field.
The system relies on gravity to move the sewage to the treatment plant. If the plant is built above ground 3 aerator pumps pump the sewage into the settling tanks. From there gravity pulls in toward the river.
The first step in the actual treatment is mixing all the stuff up, releasing the gases and exposing the sewage to air. This process is was smells so bad. It releases hydrogen sulfide, which smells like rotten eggs. From here the sewage enters long concrete tanks. Each tank is divided into two sections. In the first, air is pumped through the water.
As the organic matter starts to decay, it needs oxygen. The aeration stages supplies it with this oxygen. The bubbles lets grit settle out. The grit is pumped out of the tanks and taken to the landfills.
The water then enters its stage of sedimentation. Here the Sludge settles out and is pumped out of the tanks. Some of the water is removed for a stepped called thickening and then the sludge is sent into large tanks called digesters.
As the sludge settles to the bottom, the lighter materials float to the surface. This is called “scum” This can include anything from grease and oil, to plastics and soaps. Slow moving rakes remove the scum off the water surface. The scum is thickened and then pumped into the digesters along with the sludge. Also, many cities use filtration in sewage treatment. After the sludge is removed, the liquid sewage is ran through filters, usually sand, that removes all bacteria, reduces turbidity and color, and removes some of the odors, reduces iron, and removes any solid particles left.
Another part of the waste water treatment is getting rid of the solid-waste material. The Solids are contained for 20 to 30 days in a large, heated and enclosed tank called a “digester.” Here, Bacteria breaks down the material. This reduces the volume, odor, and destroys organisms that can cause disease. The product is then sent to landfills but also can be used as a high ammonium fertilizer.
The final step in making the sewage safe is the chlorine tank. The water flows in the tank where the chemical chlorine is added to kill bacteria. The chlorine is mostly eliminated as the bacteria are destroyed, but sometimes a neutralizing chemical must be added. This protests fish and wildlife which could be killed with a same amount of chlorine. The treated water is called effuent. This is discharged to a local river or the ocean.
In this report I told how the sewage from our homes and businesses is turned back into safe water we all enjoy. Whether for drinking or for sport, this water effects our lives every day. It seems to me that we should know how this waste is treated and is returned into our water supplies. Our neighboring county, Catawaba, Dumps its sewage into Lake Hickory. A few years ago Lake Hickory was the 3rd nastiest lake in North Carolina. The sewage station dumped raw sewage into the lake a number of times, and was fined and was almost forced to close down. The treatment plant was not big enough to handle Hickory’s sewage. The lake has been cleaned up and Hickory opened up a second sewage plant to help with the growth of the city.