With its multi-cleaning water treatment facility, London’s drainage system is now an example to the world. However, the history of London sewerage is far from anything spectacular.
There are many myths and stories surrounding the underground sewerage of London. The remains of the faulty drainage pipes can still be found buried deep within. But since then many things have changed and now London’s sewerage system has implemented advanced water conservation strategies.
The Past of the Pipes
The 1800s marked the most horrific time in the history of the London drainage system. Infamously known as the Great Stink, the diabolic waste management and drainage system had clogged the Thames River with human waste.
Then in the year 1859, an engineer known as Joseph Bazalgette worked on the process of re-designing the drainage pipes of London. His project took almost 9 years to end and it ultimately solved the problem.
Modernization of the Drainage System
The modern drainage system of London is based on several layers of waste water management system. The system ensures that the water is in its sanitary state before being flushed back to the river of Thames.
This does not only ensure the conservation of a critical resource like water but also at the same time it enables the city to implement effective waste management. London drainage system now undergoes three major levels of water purification.
The water which is contaminated with the human wastes is being transmitted to the drainage system. This drainage system is then connected to several underground pipes. The pipes lead to the sewage system.
The water which is then stored in the sewage system gets transmitted to a series of treatments. There are three stages of cleaning that take place in the drainage system of London.
Multi-Stage Cleaning Process
The multi cleaning process present in the London sewerage system starts with the screening process of the water. The items which are unsuitable are detected in this stage and then flushed away. Sometimes used water contains un-filterable objects like rags or papers along with other bio-degradable objects, flushed down the systems of residential and commercial properties.
These items are removed along with road grits using a grit extractor. Before the beginning of the multi cleaning process, all the inorganic compounds are separated from the drained water. This helps in the further processing of the water and to make it reusable.
The multi cleaning process can be divided further into three major categories. The major categories are divided on the basis of the function they perform and the steps they follow to ultimately get back to the River of Thames.
The primary treatment is associated with the process of removal of the solid waste from the water. This act is performed by pouring the sewerage water in a humongous settlement tank. The tank collects the primary sludge and deposits it at the bottom of the tank.
This makes it possible for the water above to be freed from any sort of solid waste. The sludge, at the bottom, is pumped away, providing an opportunity for further filtration of the water.
The sludge, upon further treatment, can be used as a source of generating energy for producing electricity. It can also be used as organic fertilizer.
Once the solid waste is being removed from the water, in the next step the water is further purified by pumping oxygen into it. By virtue of a well-monitored biological process, the water is then made recycle-worthy.
It is being exposed to an environment of good bacteria. It enhances the overall quality of the water. This biological process is known as activated sludge treatment and it plays a very critical role in the overall treatment of the sewerage water.
In the final stage, the bacteria with which the water was being purified, is further removed from the water itself. This process is again performed in a settlement tank. In this tank, it is the bacteria cells which form the sludge settled at the bottom of the tank.
This process is similar to the primary stage. In case of further filtration, the water is passed through a separate bed of sand. This entirely removes any kind of impurities remaining in the water.
The current water treatment system in London allows the water to be drained back into Thames and reservoirs. This water eventually becomes a source of future water supply. However, the current sewerage system doesn’t make the water worthy of drinking.