Dartmouth Sewage Treatment
How Dartmouth Works – The Sewers
Most of us are unaware how the sewer system works in Dartmouth and, in the past, it has posed a particular challenge.
Until the Victorians stepped in, Dartmouth would have certainly been a less pleasant place to live. Cess pits, for those lucky enough to have them, constantly overflowed and other households would simply have disposed of their waste water, or ‘night soil’, in the street.
Public health improved as a result of the Victorians’ investment in the sewerage network, with outbreaks of cholera and typhoid becoming less common, although a single outbreak of cholera in 1830 killed 46. Sewers were, therefore, a radical and much needed addition to the town’s infrastructure.
However the geography of Dartmouth, with its reclamation of land from the river, made this a tough and difficult task. As a result, successive generations only pushed for the bare minimum to be done.
Improvements were made, and records show that it cost £16 4s 4d per 100ft to build a sewer under New Road (now Victoria Road) in 1837.
So it wasn’t until the late 20th century that the sewage collected in this complex network received any sort of treatment. Although the Victorians were partial to a paddle in the sea, they had no problems discharging untreated sewage directly into it. Even in the 1970s, 18 separate sewage outfalls ran directly into the Dart, untreated. And while the sewer network itself was improved and extended over the intervening years, raw sewage from Dartmouth was still discharged through four outfalls straight into the Dart Estuary until 1997.
In 1989, when the water industry was privatised, South West Water embarked on an ambitious ‘Clean Sweep’ programme to build new sewage treatment works across the region and close more than 200 crude outfalls.
As early as 1992, the company started looking at potential locations for a sewage treatment works for Dartmouth. Six sites were considered, including under the New Ground car park, and the southern end of Coronation Park.
South West Water submitted a proposal for a treatment works at The Embankment. The works would have been built on land reclaimed from the estuary, totally enclosed and the top surface of the works would have been reinstated to provide a new public promenade with additional car and dinghy parking and a slipway. If the scheme had gone ahead, it was planned to transport materials to site by barge.
However, the local community was not keen, and objections poured in. South West Water, determined not to alienate the community, dropped the plans and discussions around finding a more suitable site continued.
In 1997, Dartmouth’s sewage received preliminary treatment for the first time. At the same time, two 60ft shafts were dug in the town, one at Mayor’s Avenue and one underneath Coronation Park, to store storm water.
Eventually, Dartmouth Sewage Treatment Works was built on the site of a redundant water treatment works at the head of Old Mill Creek. The £11 million scheme, which provides secondary treatment and ultraviolet disinfection, was completed in 2002.
A network of new pipes was also needed to transfer waste water from Townstal, Warfleet, Dartmouth Naval College and Dartmouth to the works. Sewage from Kingswear is transferred via a pipeline drilled under the estuary across to Dartmouth, before being transferred through the sewer network to the treatment works. The Kingswear transfer pipeline was constructed 34 metres under the estuary bed to prevent disturbing marine waters.
The treated waste water is discharged via the existing long outfall next to Coronation Park, Dartmouth. The by-product, sludge, is taken away for recycling.
Today, around 4,500 cubic metres of waste water arrives at Dartmouth Sewage Treatment Works every day. The site produces around 60 cubic metres of sludge a week, which is taken to Totnes Sewage Treatment Works for further treatment before being recycled for use on agricultural land.
Further improvements were made to Dartmouth’s sewer network in 2006, when South West Water built a new pumping station on the foreshore at South Town to transfer waste water from 35 properties between Bayards Cove and Warfleet Creek to an existing sewer in South Town Road. A further 17 properties, still discharging waste water through 11 private outfalls, were given the opportunity to connect to the new sewer. In the same year, the company replaced a section of sewer underneath Embankment Road at a cost of around £450,000.
Dartmouth now has a 21st century sewerage network – and the Victorians would be proud.
Mayor’s Avenue Sewage Pumping Station pumps between 95 and 115 litres of sewage a second to Dartmouth Sewage Treatment Works.
South West Water is in the middle of a five-year £42 million region-wide programme to renovate public sewers which have been identified as being at risk of collapse. Renovation work is likely to take place in Dartmouth in autumn 2011 onwards.
Dartmouth has a combined sewer system, apart from the modern housing development in Townstal, which means that surface water and waste water from homes and businesses is collected in the same pipe and all treated at Dartmouth Sewage Treatment Works.
Under current legislation, if your house was built after 1937, the pipes outside your property that connect you to the public sewer will generally be private. These pipes are the joint responsibility of the properties that drain into them. All that is set to change, with private sewers and drains expected to be transferred by the Government to the water and sewerage companies in 2011. Householders will still be responsible for pipes serving their property within their boundary. However, the new arrangements will remove the worry about private sewers from millions of households. Transfer will be automatic and overnight and reduce environmental pollution.
Our sewers were not designed to cope with modern disposable products such as nappies and cotton buds. Flushing these items can cause blockages, flooding and pollution.
If you can’t recycle it, bag it and bin it – don’t flush it.
First Published June 2011 By The Dart
