The Dandy Sack takes a different approach from the bags: rather than wrapping the grate, it is an incredibly strong open-top sack that hangs underneath it, with internal straps cradling the grate for support when installing and removing.

That gives it a two-foot containment area — deep enough to hold a worthwhile volume of sediment between services, shallow enough that one person can still lift it out on the straps. Installation needs no rebar and nothing fabricated on site.

Because the containment sits out of sight below the grate, servicing depends on looking in. More than one third full of sediment and the unit must be emptied; past that there is not enough capacity left for the next event.