
I paid a visit to the water treatment (sewage) works and was given a tour of the plant and how it works. Not necessarily the best place to spend your time but still it was instructive. You will pleased to know I did not take any photos.
It appears the treatment plant is actually very new. In fact much of the plant was only commissioned in the late nineties. Whilst the essence of how the plant works might not have changed the equipment and the technology clearly has.
It seems to me there are three potential areas where the odours could occur. The first is when the sewage enters the plant into a huge open well. I had always believed that the works were local but in fact they now cover an area that seems to spread from Worcester Park through New Malden, Surbiton and Kingston; a huge area to collect from.
The second "smelly" bit appears to be where air is pumped into the sewage whilst it is in beds. This clearly puts odour into the air. This part of the plant is also very close to where AFC Wimbledon/Kingstonian are based. It could well account for the odour problems along the Kingston Road - Hawks Road area which do appear somewhat more continuous than those in Berrylands.
The final area appears to be the sludge. When the water has been squeezed out the remaining sludge is sent to farms for manure. (don't ask, it surprised me as well!) Before being sent to the farmer it is stored in large open beds that run along the rear of the rail tracks, not far from the station. Most of the time this probably does not smell but when they come to load this onto lorries, for shipment to farms in the Spring and Summer, stirring it up may well cause a problem. Clearly when this happens those living in Surbiton Hill Park and surrounding areas in Berrylands may get a problem.
So what could Thames Water do about it? Well they admit that they could prevent it. It would be possible to cover those areas that present these problems and they would need to install very large air purification plants to cleanse the air inside the cover, although it would be very expensive. They even reminded me that some plants have tried an aerosol technique to clean up the air but this had limited results.
However, they cannot just invest where they might want to. Despite being a privatised company they can only invest in areas of their operations where the Water regulator agrees. The priorities set by the water regulator for the next five years are to invest billions in upgrading the water delivery infrastructure (pipes, drains etc.). As you are probably aware the system of pipes in some places date back to Victorian times and have huge leakage problems. Thames Water anticipate that 30% of their clean water leaks out of their pipes. Pipes are priorities for now, not water treatment plants.
So it looks as if the next stop is the water regulator! Wish me luck?
However, I have asked that Thames Water consider what they might do to improve relationships with the people living close by. They have agreed to have a look at what they can do to keep residents up to date with issues. This would have been particularly helpful over the Summer when they had the major break downs that caused such problems. They also know the areas of Kingston that are most directly affected by odours. I shall keep up a dialogue with them on this aspect.