Council using cameras to survey subterranean sludge

Date: 
Fri, 03/11/2017

 

Make the Polluter Pay 

A sewerage surcharge is being proposed in Westminster in a bid to stop building material clogging up the city’s gullies.

Gullies are drains that take water away from the street into the sewers below. They often block around building sites because people have poured commercial waste – such as sand and concrete – down them.

Westminster City Council is looking to implement a programme to ensure licensed building sites are covering the costs of cleansing gullies next to their premises.

The council regularly monitors its gullies. When they block the team analyses what has caused the pollution and routinely find materials such as sand and concrete emerging as the main cause.

Blocked gullies can cause a host of problems including: flooding, damage to the carriageway, surrounding infrastructure and property. Sometimes, as a last resort, cars have to be lifted off the street to gain access to a drain which is both costly and time consuming.

Last year the street cleansing team were called to a gully that was bubbling with an unidentified florescent green liquid and a gully near Oxford Street was found blocked by five full sand bags.

Councillor Danny Chalkley, Cabinet Member for City Highways, said: “Washing concrete into a drain might appear to be a small act but that material builds up in the city’s gullies. Blockages are a huge nuisance and can cause flooding that damages properties.

“Westminster City Council is using innovative methods to combat the problem, including the use of CCTV to explore the capital’s gullies.

“Construction is an important industry in the city and we work closely with our builders. But we cannot have silt waste going down our drains and it is unfair the taxpayer has to subsidise the cleaning bill. We think it’s fair that when it’s deliberate, the polluters pay.”

Councillors are expected to make a decision on the proposals later this month, with a view to implement the project in January 2018.

The charge will be incorporated into structural licence fees, which firms sign up for online. The fee will be based on the number of gullies likely to be affected by their works.

It will cover a charge for the council’s contractor and staffing costs associated with the activity.

CCTV Surveillance of Subterranean Sludge

CCTV surveillance is going underground in a drive to understand what is happening beneath the streets of London. 

Westminster City Council has embarked upon a large drainage improvement plan – thought to be the most extensive gully operation of its kind in London.

The operation, with the council’s contractor FM Conway, involves using CCTV cameras to monitor what is happening in the pipes below our streets. The CCTV footage is helping the council discover pipes and gullies it never knew existed and to create a comprehensive inventory.

Central London has an aging drainage network, with many old pipes made of clay.

The cleansing teams do not know the condition of the pipe until they send in a push rod camera. The footage reveals if repairs are needed.  This is a progressive step, moving from a reactive to preventative approach to asset management.

If a pipe is damaged the team pump in a liner, followed by a resin, which solidifies and creates a new lining which will last for up to 25 years.

This saves intrusive street digging work that can be particularly disruptive for residents.

However, if a pipe has fully collapsed, no amount of lining will fix it and the pipe will require digging work.

 

Key facts:

  •  Westminster City Council maintains 16,500 gullies
  • Since July, 200 gullies have been surveyed with CCTV
  • 95% of a gully’s content is recycled. Sludge is taken to FM Conway’s drainage treatment plant where material is separated into solids, organics, and water and reused as aggregates and materials in their wider construction business

Gold jewellery, knives, number plates and dozens mobile phones are just some of the objects pulled out of gullies in Westminster.

In order to retrieve people’s possessions the street cleansing teams have to suck out the silt and use picker to retrieve the item.

Some of the more unusual findings and requests the gully cleansing teams become involved with include:

  • Knives, including an alleged murder weapon, at the request of the Metropolitan Police
  • Personal property such as car keys, number plates and mobile phones 

Last updated: 8 November 2017
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