sewage water purification/Bulk purchase price And retail
In a case study about water treatment, we discussed Germany as one of the countries that use sewage water treatment plants for water purification.
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The main question to be answered here is what is this method exactly? We go through the details of the sewage treatment plant, so stay with us.
Over ninety-five percent of the country of Germany's population, which totals 79 million people, is connected to the public sewage system (2004).
More than 10,000 sewage treatment units are responsible for cleaning up used water.
The length of the sewage system is roughly 515,000 kilometers, which is sufficient to make 13 full rotations around the earth.
In most cases, the responsibility for wastewater treatment facilities lies with the local governments.
However, there are also sewage treatment plants in an industry that are privately owned and operated.
Public wastewater treatment plants are responsible for cleaning up around 9.
4 billion cubic meters of sewage every single year.
Almost one hundred percent of the wastewater is purified through the following three phases in the sewage treatment plants:
a stage with mechanical elements,
a stage of biological development that does not include the removal of nutrients such as nitrogen and phosphates.
an extra stage of biological purification that focuses on the removal of certain nutrients.
The number of institutions that use biological methods to handle waste has been steadily growing in recent years.
Because of this, there has been a promising increase in the quantities of oxygen found in all bodies of water, which has resulted in enhanced living circumstances for fish fauna and other aquatic species.
The many processes involved in a contemporary sewage treatment facility
The first stage of purification is known as the mechanical treatment of wastewater.
At first, the wastewater travels through a bar screen.
This screen catches bigger solid particles like paper, bottles, branches, and tins, and then an automated motorized rake removes them.
The sewage channel widens out when it enters the grit chamber, which slows the flow of the entering sewage and makes it possible for coarser particles like gravel and sand, which are denser than water, to sink to the bottom of the chamber since they are heavier than the water.
The water is held for roughly two hours in the primary settlement tank before it is drained.
In this enormous settling tank, which may be rectangular or spherical in shape, small suspended particles have the potential to settle as sludge at the bottom.
This raw sludge is separated, allowed to get more viscous, and then sent to a digestion tank.
Light particles that are floating on the water's surface, such as fat and mineral oil, are collected with a skimming device and then transferred to a separate tank.
The first step of purification is comprised of the first three phases.
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Because it consists entirely of treating the wastewater using mechanical means, this step is also known as the mechanical treatment stage.
At this step, roughly 30 percent of the contaminating stuff that is present in the raw wastewater that the plant is required to handle in its entirety is removed.
The biological treatment of wastewater constitutes the second stage of purification.
In the second stage of purification, also known as the biological stage, a natural procedure is employed.
This process consists of placing the sewage liquor in an aeration tank.
During the process of activated sludge, oxygen is added to the liquor to produce favorable circumstances for the growth of microorganisms.
These microorganisms feed on the organic particles that have been solved in the affluent and accumulate the matter that they have consumed.
During this process, contaminants such as heavy metals and other pollutants are taken into the body.
A huge variety of different microorganisms may be seen forming colonies, which are known as flocs, in the sludge.
These sludge flocs will eventually fall to the bottom of the subsequent secondary settling pond or clarifier, where they will either be pumped back into the main settling pond to be disposed of as sludge or sent back to the activated sludge process.
Because of this, the elimination of biodegradable contaminants in the effluent is contingent upon the removal of the sewage sludge.
Smaller sewage treatment plants frequently make use of trickling filters, which are circular concrete tanks that are only lightly filled with porous pebbles.
These rocks give the bacteria the enormous surface area they require to settle.
They do this by forming a continuous film known as a "biofilm," which is analogous to the sludge flocs that are produced during the activated sludge process.
The effluent is then passed over this film.
The effluent is cleaned to an extent of roughly 90 percent after going through the phases of mechanical and biological treatment.
Additional treatment of wastewater constitutes the third and last stage of the purification process.
Today, wastewater is typically contaminated with chemical compounds like nitrogen and phosphate, which necessitates the use of extra specialized procedures, like the following:
The fluid that contains phosphate that was obtained from the secondary settling pond is initially introduced into a flocculation tank.
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At this point, the effluent is subjected to a vigorous mixing process, and at the same time, a dosing pump for precipitants is simultaneously dispensing a chemical solution into the liquor.
This precipitant has a chemical reaction with the phosphates, which results in the formation of a compound that is insoluble in water.
Additionally, the leftover pollutants create flocs, which result in sludge being settled in a subsequent clarifier.
This sludge is then allowed to get more viscous before being sent to the digestion tank.
The purified wastewater can be released back into the surrounding natural ecosystem at this point.
Treatment of sludge and disposal of it
A total of roughly 98 percent of the sludge that is collected throughout the two phases is composed of water.
By adding thickening agents, it is possible to lower this percentage down to 96 percent, which results in a volume reduction of sludge of around 50 percent.
After that, the sludge is transferred into a tank that is used for digestion.
The process of anaerobic fermentation results in the production of digester gas at a temperature of 35 degrees Celsius.
This gas is composed of two-thirds methane and one-third carbon dioxide.
This fuel gas is kept in a separate tank until it is needed as a source of heat for the building.
After a period of about four weeks, the digestion process is finished, at which point the odorless sludge is released into a sludge-drying bed for dewatering.
Larger industrial companies typically operate their sewage treatment facilities, which include technological procedures that have been customized to the particulars of their operations.
In the western part of Germany, almost 90 percent of the population is connected to the public sewage system, but in the eastern portion of Germany, the percentage is closer to 66 percent.
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