my limited knowledge might explain the pollution topic, north side of the airport - bravo apron - drains run via pipes into an underground tank next to the spitfire museum carpark, this is then pumped away along pipes under the grass next to echo taxiway. south side of the runway has drains running along it which run into an underground pipe that goes under cliffsend to pegwell bay.runway surface fluids also run to a separater tank adjacent to a taxiway any form of surface fluid runs into these drains and tanks.
Bravo apron works nearly complete, echo apron has had the surveyors in for possible extension.