I'm not up on the latest Tymco lingo or models, but with their regular 600 models, we routinely use them without any ground water, and with very little perceptible air-borne dust, and no pre-mature abrasive sand-blast action on the fan. Here's how we did it:
First, make sure there's absolutely no leaks in the system anywhere. Rubbers good, hoses tight, doors sealed, etc... To test this, we go around the system, while it parked and fully on, with a cottom ball. Put it anywhere you suspect is a weak spot (pinholes in the tubes, every part of the head, etc...) if you find a spot where the paper cotton ball wants to blow away, or suck in (depending on if it's @ the suck side, or the blow side), then there's a spot to patch or fix up.
Next, fill the hopper about 1/4 way full of water. If it starts dripping out, that means you didn't have a good rear door seal (try toggling closed tighter, etc...). Don't trust their in-tank water sprayers, use a 1/4 tank in the rear hopper, which will turn to vapor, and slosh around, once you get moving and the air is blasting in there. This is as good or better than the Tymco's wimpy in-tank water system, and will suppress the dust before it's able to suck up through the fan.
Of course, this won't stop the dust at the gutter broom, so you may elect to aim a single sprayer there, if you are doing a curb job.
We used to to a lot of sealcoat jobs where we could not use groundwater (it seals in smears, and is a barrier that can stop the oil from sticking). Yet of course we couldn't spew dust in the air, lest it just settle back down, and the lot not be clean anymore. Plus of course, we didn't want complaints from people getting their cars dusted
This even worked for fine dusty silty dirt. We once swept a series of municipal streets that had a baby powder fine powder all over them (ground-down poor grade chip, which was getting kicked up into the air by all the passing cars). This city kept calling out the competition, who tried to sweep it with a Mobil. Naturally, he'd use groundwater. A few hours later, when the sun dried the slime, it was back to where it was before. It was as fine as ash by now, and in drifts several inches deep for blocks lengths on end. We were able to sweep it up, with no ground water, and only minimal pig-pen whisps of dust around the head (like when you went over a pebble and head momentarily rises up).
So it can be done, but this degree of perfection is overkill and expensive for standard municipal sweeping. The average city is flying along and trying to make time and distance and just get the bulk.