Onboard Sewage Treatment System

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Here we are going to discuss the onboard sewage treatment system. It is banned to discharge the sewage wastes to some controlled area and territorial sea area by the IMO. It is the international Legislation that avoids sewage discharge to these areas. Also, these area having a specific distance from the land. Because of this, we should treat the sewage onboard itself. Therefore all the new ships are launching with installing the sewage treatment plant.

If the sewage is not treating well, then it will be affecting the marine environment badly. The sewage should break down naturally. For this breaking down, it needs more content of oxygen. Then it will reduce the amount of oxygen in the water. And thus the marine organisms will suffer. Also, the fishes and marine plants will die. The bacteria in the sewage will produce hydrogen sulphide and cause a pungent smell. One kind of bacteria seen in the human body known as E. Coli is present in the sewage. The measure of this bacteria in a particular amount of the water will give the intensity of the sewage content.

There are two types of the sewage treatment plant onboard ship. Chemical treatment and biological treatment. Also, the chemical treatment is the arrangement to store the solid particles and discharging them into the permitting areas. Also, the biological treatment is the arrangement of treating the sewage and it can discharge inshore.

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Onboard Chemical Sewage Treatment System:

This is an onboard sewage treatment system. This treatment will reduce the amount of sewage. And treats again and again till it can discharge. Some shore has the arrangement to take the sewage. This means the chemical treatment of sewage arrangement will hold the sewage as long as the ship in the control area. In this system, the liquid content in the sewage will be removing. And it is allowed to discharge the washbasin and the bath drains overboard. Also, the water from the closets will be treated at maximum efficiently. And then it will use for flushing. The water from the closet should treat efficiently till the smell and the colour disappear.

In the chemical treatment system, various types of chemicals will be used at many points of the process. This will help to get good odour and also for removing the colour. This chemical will also help to breakdown the sewage. There will be an arrangement of comminutor. This will help to breakdown the sewage physically thereby helping the chemical breakdown process.

The solid wastes will be store in the particular tank and the liquid content will use for flushing. The tests for the tank should carry out correctly and check the chemical quantities are correct. This will help to avoid corrosion.

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Biological Sewage Treatment:

This is an onboard sewage treatment system. In the biological sewage treatment, we will be using bacteria to promote the breaking down of the sewage. And thus discharging into the water. There will be a high aeration process. This will help to provide a good oxygen atmosphere to the bacteria. Also, these bacteria will grow more gradually, thereby breaking down the sewage. Afterwards, convert it into sludge. These bacteria are known as aerobic bacteria. The biological treatment process has three watertight compartments.

1. Aeration compartement.

2. Settling Compartment.

3. Chlorine Content Compartment.

The sewage will initially move to the aeration compartment. Because of this aerobic bacteria and micro organism present there, the sewage will digest. After this, the sewage will move to the settling compartment. There the sludge will settle down. And the liquid content will move to the chlorinator. The remaining bacteria will remove from there. And then the liquid will discharge. The sludge that settled down in the tank will recycle regularly. And can discharge into the decontrolled area.


Conclusion: Hope you got the idea about the sewage treatment plant onboard ship. comment your opinion and your queries below.

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