Final answer:
A vented trap prevents sewer gases from entering buildings and maintains a water seal. It should be located after the trap, allowing gases produced during waste decomposition to escape safely. The Great Stink of London in 1858 highlighted the need for properly designed sewer systems with such features.
Step-by-step explanation:
The purpose of a vented trap in the connection of a building or house sewer to a municipal sewage disposal system is mainly to prevent the escape of sewer gases into the building and to maintain the water seal that keeps those gases out. The vent should be positioned after the trap itself, allowing gases that are naturally produced during waste breakdown to be safely released into the atmosphere instead of into the building. A properly functioning vented trap is a critical component of a sanitary sewer system because it ensures that sewage and waste water are appropriately transported away from the residence without allowing harmful gases to enter living spaces.
During historical events like 'The Great Stink' in London, the need for sophisticated sewage management systems became very clear. The rebuilding of London's sewer system, lead by Joseph Bazalgette, is an important milestone in ensuring public health and the proper treatment and disposal of human waste, similar principles underlie modern sewer system designs, which include vented traps.