During our work last year in Wentworth, New Hampshire we came across a "bit of creativity" during the 2-hr tanker shuttle operation. The folks had made a device out of PVC pipe so that pumpers could pump off their tank water into a dump tank without blocking up traffic at the dump site. It was nothing fancy and it worked. You do have to use caution with pressurizing plastic pipe, make sure that you use pipe rated for pressure. But as long as the open end of the pipe does not get blocked, there really is no back pressure generated.