[bix6]

Not true. The non profit might add a screen to catch pollution before it hits the waterway.

[appreciatorBus]

Sure they might do that, just as a for profit company might.

The decision by either would face the same trade off - an increase in costs that their customers/patrons may not care about or be willing to pay for.

The answer for both is the same - price externalities so that the decision to pollute less is economic rather than moral.