EDINBURGH’S ancient nickname of Auld Reekie came from the tens of thousands of coal fires that used to drape the capital in smog.

For many years now the capital has been plagued by a new reek, which is confined mainly to the east side of the city and comes from sewage being treated at the Seafield Waste Water Treatment Works between Leith and Portobello.

A report to the council’s Transport and Environment Committee on Thursday will show “a significant increase in complaints from April 17 to May 31 2017, with a total of 143 complaints received by the council during that period.”

The report states that the increased level of complaints can be attributed to two factors. During that period, the council was notified by operators Veolia Water of a series of spillages of sludge between April 30 and May 6.

Monitoring staff made a number of visits to Seafield, which indicated that “the extent of the spillage and the detection of associated offsite odours was likely to be a major contributory factor in the complaint surge.”

Scottish Environment Protection Agency officers also attended the works and expressed “an alternative opinion that the complaint surge related more to recent low flows of water into the sewerage network”.

The report concludes: “As the increased complaint level continued after the digester spillage had been removed, it is likely that both the spillage and the low flows of influent combined, creating the levels of odour nuisance experienced by local residents during April/ May 2017.”

Veolia’s general manager gave a local presentation on the increased odour risk due to low influent flows during dry periods of weather and the company has stated that it “is statistically likely that such dry periods will occur in the future and therefore the council is in discussion with Scottish Water on how they intend to minimise the risk of odour release at those times.”

The Scottish Government has commissioned a full strategic review of Seafield to look at operation, design and maintenance of the works, which is due by the end of this month.

Transport and Environment Convener, Councillor Lesley Macinnes, said: “The council has been in contact with Veolia Water and Scottish Water on how they intend to minimise the risk of odour release, while we are also currently awaiting the outcome of a full strategic review of Seafield by the Scottish Government.”