For reasons not relevant here, I have a spare water heater drain valve with a thread matching the drain valve for the Can-o-Worms bin:
It lacks the flange required to seal the O-ring against the outside of the bin, but I can fix that:
It’s a chunk of PVC pipe faced to the proper length, bored to fit the valve body, then gooped in place with acrylic caulk.
Snug the nut inside the bin and it’s all good:
The original valve depended on having a smooth plug turning inside the outer shell, but years of grit scarred the interface enough to produce a slow drip. It also had the annoying mis-feature of aiming the opening inward, between the bin legs, where a jug didn’t quite fit.
The water heater valve depends on compressing a smaller O-ring against a seat inside the body, which may tend to clog with crud. We added a mesh filter to hold back the worst of the gunk, so this is in the nature of an experiment using free hardware.
The Smell of Molten Projects in the Morning 