[pairodice]

Where can we get a bucket shown in the picture please? 

"The picture below shows a square five gal with a Valterra style slide valve bolted directly to one of the flat surfaces.   The valve has the "hook" side of the most common fitting.  There is a hose with a mating connector for the valve (not shown yet, waiting) of which the other end is slipped over the tailpiece of the Waste Master and hose clamped.  The waste truck operator puts his nozzle into the square five gal and draws a vacuum while the effluent is filled into the five gal from the coach.  The opening in the five gal is large enough to allow ample air to flow in. "