Pollution in Wastewater: Types and Removal Essay Sample
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Pollution in Wastewater: Types and Removal Essay Sample
Techniques in managing and treating wastewater are state of the art and not used in every city of The United States. Some cities still use more old fashioned sewage techniques to clean their water. There are a plethora of pollution types, but one of the most common is wastewater pollution. This directly affects our daily lives due to the fact, that water is an essential part of life. Not only is it for drinking, but it is also vital for sanitation and irrigation. There are four different types of wastewater pollutants; Debris and grit, Particulate organic material, colloidal and dissolved organic materials, dissolved inorganic materials, and all four are treated before being released into water ways.
There are a plethora of pollution types, but one of the most common is wastewater pollution. This directly affects our daily lives due to the fact, that water is an essential part of life. Not only is it for drinking, but it is also vital for sanitation and irrigation. Wastewater treatment facilities were designed to treat the outflow before entering the receiving waterways. The ideal modern system collects storm water separately from wastewater and treats it to remove all pollution, but that has become a difficult task. There are four different types of wastewater pollutants and all four are treated before being released.
The primary treatment in removing pollutants from wastewater is the removal of the first type of pollutants, debris and grit; like, plastic bags, gravel, course sand, rags, and other object disposed in toilets or washed through storm drains. These pollutants can later damage or clog pumps, so they are quickly removed after exiting the raw sewage. This removal involves two steps; screening of debris and the settling of the grit. The raw sewage flows straight threw a bar screen. The row of bars automatically rakes the debris and then the water enters the incinerator. Then the water is taken to a grit chamber where the speed is slowed down. Therefore, giving the grit time to settle. The grit is then mechanically removed and taken to landfills.
Water continues on its track entering the primary clarifiers. These are large tanks where particulate organic materials, like food wastes, toilet paper, and fecal matter are left motionless for hours. This causes about 30%-50% of the organic materials to settle at the bottom of the tank where it can later be removed. While fecal-mater, foods, and paper settle to the bottom of the tank, oils and fats float to the top of the water where they are also removed. The fatty materials and organic materials are then put together to make raw sludge. This very simple treatment removes plenty of the unsanitary pollutants that live in the water.
The secondary part of this treatment is called the biological treatment. The reason for this is because it uses natural decomposers and detritus feeders. In this part of the treatments colloidal and dissolved organic material pollutants such as, bacteria, urine, very fine particles of particulate organic material, detergents, soups, and other cleaning agents are removed from the wastewater. Oxygen is added to the water through trickling-filter system or an activated-sludge system. Both these systems ass oxygen to the water so that the organisms in the water can feed on the colloidal and dissolved materials. Therefore, breaking it down to mineral nutrients, carbon dioxide, and water through cell respiration. The activated-sludge system is the most used secondary treatment. An air bubbling system and a churning system is placed in the tank along with activated sludge. The tank is well-aerated causing the organisms to feed on each other forming flocs. Then the water flows to a second clearing tank where 90% of the pollutants have been removed.
Finally, public-health laws demand that water be completely disinfected before discharging into water ways. Therefore, the final cleaning and disinfection must take place. Although the water has been 90% cleaned and few pathogens survived, there are still dissolved inorganic materials in the water, like phosphorus, nitrogen, and other nutrients from excretory wastes and detergents. Chlorine was often used to clear these last bit of pollutants, but it has been proven to affect animals and humans, so sodium hypochlorite, more commonly known as Clorox, is a safer more efficient chemical now used. Other, not as common, techniques are ozone gas and ultraviolet light.
In conclusion, the water is released into water way and then repeats this step again. These techniques are state of the art and not used in every city of The United States. Some cities still use more old fashioned sewage techniques to clean their water. Wastewater pollutants are very common and thankfully we have found a way to deal with the issue. Pollutants directly affects our daily lives due to the fact, that water is an essential part of life. Not only is it for drinking, but it is also vital for sanitation and irrigation.
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