We had a terrible blockage at our manhole, which the previous owner covered with decking (we don't know why either). The drains are now clear, but sewage seeped out from there and ran under our decking. Any ideas of how to get rid of the smell? How long does waste like this have an odor? Any way to treat it without taking all of the decking up? Please help! Summer is coming and the heat will make it unbearable.