The front page article in The Isle of Thanet Extra today is about ground water pollution here in Thanet, with comment from our two MPs.
Reading the article it was obvious that although both MPs had attended a meeting with the environment agency about ground water quality but didn’t really understand the problems properly.
This is essentially about five different types of drain and understanding the differences between them.
1 Foul sewers these lead to a waste treatment plant, the water and effluent from these is treated and the treated water then goes into the sea.
2 Soakaways, these are often roadside drains the water from these soaks into the chalk, which also forms our drinking and agricultural water reservoir, some of these have interceptors that remove any fuel or oil spillage (how effective they are depends on their size relative to the size of the spillage and how well they are maintained) some of the don’t have interceptors.
3 Direct discharge into the sea, once again these are mostly roadside drains some with and some without interceptors.
4 Septic tanks these are mostly attached to rural properties and are emptied by the council the effluent being taken by tanker lorry to the treatment plant, the problem with these is that many of them leak, either by accident or design. Having them emptied is expensive so people sometimes make a hole in them so they don’t have to be emptied so often.
5 Private treatment plants such as Pfizer has and China Gateway wanted to have, these use bacteria and sedimentation to process the effluent the processed water is then either discharged into the sea or soakaways. Where China Gateway came unstuck is that discharge into soakaways on the water source protection zones is not allowed.
Roger Gale appears to think that industrial developers and the airport don’t play a significant part in the ground water problem, he is quoted in the article thus: “…it isn’t necessary to fault big business or the airport; it’s all down to us.”
The pollution problem that the environment agency faces is that the quality of the ground water is low and this is mostly caused by a great many small leaks and spillages.
The other problem that they face is that we are around the point where any more concreting over the source protection zones means that there will not be enough surface area for the rain to soak into to provide us with sufficient water supply.
Because of the various large pollution incidents like Thor and Sericol the amount of underground water that we can use has become greatly reduced and is concentrated around Manston.
This leads to the problem of what we can get away with at Manston both in terms of airport and industrial expansion, which poses the question how much more dare we concrete over? And the question of how much risk is acceptable in terms of a pollution incident there?
As far as the concreting, the environment agency needs to set defined limits to how much more there can be so that the airport and the industrial developers there know where they stand in terms of expansion.
Most importantly though is the problem of how the risk management is assessed for a fuel spillage caused by an aviation accident, having spoken to a lot of people that understand aviation a worst case scenario would be something akin to the recent air accident at Narita international airport, near Tokyo.
By this I mean an air crash on the grass part of the airfield where the fuselage of the aircraft runs over the wing that contains the fuel tanks rupturing them. The 747s flying to and from Manston can carry 50,000 gallons of fuel so a spillage of 20,000 gallons would not seem out of the bounds of probability.
Although there are many variables we need a clear cut answer from the environment agency as to what quantity, for both types of aviation fuel, would cause irredeemable damage to our essential water supply and to restrict the airports operations accordingly.
I noticed in the article Steve Ladyman said that the risks at the airport were being managed properly, however at the moment the main runway has no fuel interceptor, the contingency plan being to turn off the valves from the drains and contain a fuel spillage on the runway.
In reality with a plane on fire with people inside I wonder would they really stop the fuel from running away? So we really need an assessment of the maximum amount of fuel that should be carried by aircraft using Manston, until the interceptor is installed.
Of course there will always be a risk that our underground water supply will be irreversibly damaged by an air crash and I am afraid it would probably be the end of most of the agriculture in Thanet including Thanet Earth, it would also lead to greatly increased water bill for us. What this is about though is acceptable risk management and in the current economic climate with a doubling of unemployment in Thanet during the last year local industry badly needs to know exactly where it stands in terms of future expansion and future limitations on existing levels of operation.