bleach

[dustypuss]

hi how dose sewerage works get rid of all the bleach and liquid chemicals that go down the loo before discharging in to our rivers

[theprof]

Many different techniques are used to get rid of harmful chemicals. The physical and chemical methods used usually include the following:

Neutralisation. This is the adding of chemicals to sewage in flotation tanks to make it pH neutral. Acids and alkalies are in most cases turned to relatively harmless salts in this way

Heat. Volatile chemicals are removed in some countries by heating the sewage to a temperature that vapourises these volatile substances.

Chemical Coagulation. This is the adding of specialised chemicals to the tanks that cause other chemicals to cling to them. The mass is then effectively skimmed off.

Specific Gravity removal. Chemicals are added to the sewage that cause fats and oils to separate from the water component (de-emulsify) rapidly. Again the fats and oils are skimmed off.

Flotation. Some chemicals and other substances will simply float to the top of the water component on standing. Again they are removed by skimming.

These are just some of the methods used. Biological treatment with bacteria is also very important as the bacteria are capable of rendering many harmful substances harmless.

[dustypuss]

thank you verry much