What is sewage?
This may be used to describe raw sewage, sewage sludge, or septic tank waste. Raw sewage is mainly water containing human waste, industrial effluent and debris, such as sanitary towels, condoms, plastic etc. The major source of harmful micro-organisms, including bacteria, viruses and parasites is sewage; although sewage treatment does reduce the water content and removes debris it does not kill or remove all the micro-organisms. Exposure to sewage or its products may result in a number of illnesses.
What was known as the ‘great stink’ once was mended by introducing giant sewers, treatment works and pumping stations by the act of the Parliament centuries back in London and this very system now forms the basis of the sewer system in London. It had been engineered by Sir Joseph Bazalgette. Though it has been improved upon many times over the centuries, but still it forms the main framework of the entire sewer system.