Sewer Developments in a Historical Perspective

The sewer network we know today is a relatively new infrastructure in the cities. Not until the middle of the 19th century did it become common to construct underground wastewater collection systems in European cities. London and Paris were among the first, but other cities followed rapidly. The first sewers developed from the storm drains, which now were allowed to receive waterborne wastes from flush toilets, converting the drains into combined sewers. A major reason for collecting the wastewater was the enormous problem of unpleasant smell from the open sewers, cesspools and privies and the requirements for space in the streets in the densely populated cities. 

The older parts of the cities in Europe and the United States were typically served by combined sewer networks with outfalls from where the excess 

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