In the early days of the steam engine’s success, what helped it find an economic footing was the need to pump water from coal mines. At the time, logistics of transporting things over large distances were difficult, so having the coal supply on-site was an obvious benefit. So while using a steam engine to pump water from a pool would be quite archaic and inefficient, but at least for emptying the pool, it could technically be used.

Of course, a locomotive moving the engine around would be entirely impractical for pumping a somewhat steady stream. Chlorinated water would also make for poor steam, I imagine.

I guess driving a scrubber back and forth would be possible, but I could do that more efficiently by hand. I drink less water, eat less coal, don’t require rails and skilled operators and I’m easier to transport to the site. I’m not sure how the carbon footprint for a human compares to that of extracting and processing iron, but it won’t be favourable if at least one human is involved.

The scrubber couldn’t be as large and heavy though. If you need a heavy scrubber, you’d also need a powerful motivator. That’s where a steam engine might have an edge over me: sheer power output.

To match that, you’d have to employ and pay multiple people. So if the steam engine’s rent seems cheaper than that…