I have never known of a seal being required at the dump site. If you are at the dumper with your trailer in tow I would just use a reg slinky hook up. The macerator is more for a situation where you need to either dump where there is no connection or using a blue boy. We use our macerator to push waste into a blue boy located in the bed of our truck. We then drive to a safe dumping location and dispose of it. I do not like to crawl along at 2 miles and hour pulling a load of human waste for who knows how far. Nasty accident waiting to happen.