Thames Water has apologised for the stench of sewage, which caused weeks of misery for residents in the Beddington area, and assured residents a long-term solution is in hand.

A fault at Beddington Sewage Treatment Works in August caused the foul smell – dubbed the Beddington pong – that drove hundreds of people indoors and forced them to close their windows during one of the hottest spells of the summer.

Last week, representatives from Thames Water attended a meeting of the Hackbridge Community Forum to say sorry for the stink and they told residents money was being invested in the site to improve the long-term situation.

They explained that the stench was caused when two of the three “digesters” at the site – huge tanks in which bio-degradable sewage is broken down by bacteria – overheated and failed.

The situation took several weeks to rectify.

And Will Ransford, contracts manager for Thames Water, said: “We are in the process of building a dewatering plant at the site.

"The technique removes the water from sludge and turns it into a cake material, which will be stored in Dutch barns before being transported to be spread on farmland.

“The odour from the cake isn’t negligible but it’s far less odorous than the current system and far less concentrated, and should mean things improve dramatically.”

He said if the plan was given planning permission, the dewatering plant and the first Dutch barn will be built by the end of November, with the second barn in place in July 2013.

Councillor Colin Hall, Sutton Council’s executive member for environment and climate change, said: “We have been putting pressure on Thames Water to tackle the situation at this site for some time so I am delighted it has apologised to residents and signalled its intent to invest money there and improve things.

“The latest problem affected hundreds of people living up to three miles away so it is high time that Thames Water took action to make things better.”