No swimming signs on Broughty Ferry beach prompted memories of the bad old days for water quality on the Tay.
Scottish Water put up the notices around Broughty Ferry and Monifieth beaches in August.
The signs came after the pumping station near Riverside Tescos in Dundee stopped working on as teams repaired a broken sewer.
The incident meant Scottish Water had to fall back on an outfall pipe that dumps waste deep out in the Tay.
Workers took around five days to repair the sewer with the no swimming signs lifted just under a week after the incident.
Scottish Water uses the outfall pipes into the Tay in an emergency.
They come into play either when the system has broken or when heavy rain or storms force too much waste water into the largely Victorian-era sewer network.
That’s slightly different to the situation in England where private water companies have been more ready to pump sewage into rivers.
The public has criticised Conservative MPs for failing to clamp down on it.
Sewage in River Tay common in the 90s
But although problem is more pronounced south of the border, sewage discharge also happens in Scotland.
Authorities used to pump human waste into the Tay regularly before the Hatton Wastewater Treatment Works opened in the early 2000s.
The large treatment facility between Carnoustie and Arbroath cost £100m to build before starting operation in 2001.
Today, a network of seven pumping stations placed between the west end of Dundee and Arbroath carry human waste along 35km of pipes to the plant.
Machinery processes the waste. The plant then discharges the waste water into the North Sea.
Seeing the clean water pooled and ready to go is an impressive sight – even if the odour at the facility is not one you would ever want to remember.
River Tay sewage breakdown puts system in emergency mode
But that is if everything is working as it should.
The sewer breakdown led to workers shutting down the pumping station at Riverside.
The volume of waste quickly overcame the emergency capacity at Riverside.
That meant discharge into the Tay, hence the advice not to swim on Broughty Ferry and Monifieth beaches.
The alternative could have seen sewage backing up the system into people’s homes.
These days, Broughty Ferry beach enjoys an “excellent” rating from Sepa and attracts day- trippers, wild swimmers paddleboarders and others from miles around.
But it was not always known for its cleanliness.
Prior to Hatton opening, environment group Friends of the Earth branded it one of the worst in Scotland due to the waste pumped into the river at low tide.
The quick and almost immediate improvement in water quality on the Tay was one of the Hatton project’s great selling points.
Bathing water quality affected in ‘worst case’ scenario
Scottish Water stress the distance between its outfall pipe and the beach is still a significant one.
And it is only used in an emergency or during heavy rain and stormy weather.
Scottish Water modelling suggests bathing water on Broughty Ferry beach could be affected by the sewage discharge only under a “worst case” scenario.
But that has still been enough to merit the “precautionary” signage that appeared in August.
And serves of a reminder as to the relatively fragility of the city’s sewage system.
Conversation