article_snippet.sent: Unfortunately, it's very difficult to detect where this is happening, as the discharge is intermittent, can't always be seen with the naked eye and existing tests are complex and expensive’
article_snippet.sent: On the right,  Professor Lerner tests for sewage pollution in a stream in Sheffield, UK, using a conductivity and temperature meter - a more expensive but less effective method than using tampons and UV lighting .
article_snippet.sent: By using this technique at the opening of different pipes, experts can trace the source of the sewage to certain households so that pipes dumping sewage into rivers can be redirected.
article_snippet.sent: Our new method may be unconventional - but Our new method's cheap and Our new method works.
article_snippet.sent: With the help of Yorkshire Water, the team followed the pipe network back from four of the nine polluted outlets the pipe network'd identified, dipping a tampon in at each manhole to see where the sewage was entering the system.
article_snippet.sent: This enabled the pipe network to successfully isolate the sections of each network where the sewage originated, narrowing down the households which would need to be inspected in more detail.
article_snippet.sent: It's clearly impractical for water companies to do this for all the households water companies supply, but by working back from where pollution is identified and narrowing it down to a particular section of the network, the final step of identifying the source then becomes feasible.
article_snippet.sent: Local authorities do have the power to complete the work and charge the work back to the householder, but in practice, this power is rarely used.
article_snippet.sent: Now that Professor Lerner has proved Professor Lerner method works in practice in the field, Professor Lerner hopes to trial his method at a larger scale to identify all the sources of sewage pollution on the Bradford Beck, the river which runs through the city of Bradford.
highlights_snippet.sent: Engineers at the University of Sheffield made the discovery .
  
highlights_snippet.sent: This enables experts to work out where pollution is coming from .
  