When they ask if you can/want to do a type of work and the simple answer is ‘No’, never directly say no but instead talk around your limitations in as positive a way you can.
Replicated food is made of recycled organic molecules, same as regular food.
Once you start worrying about what something was in a previous existence, you realize tap water is recycled dinosaur pee and molecules have no identity.
Heat exchangers are extremely efficient. You use the 500C water to heat 400C water, then use your 400C water to heat 300C water etc etc. It still takes energy, but you recover over 90% of it.
Stopping pollution is difficult, and filtering water is expensive, but boilers are well established technology.