There's not much commercially available to convert such waste heat to electricity. Here's an interesting article on some research in this area.
A peltier junction is probably as good as you can do, although the efficiency is low.
A sterling engine driving a generator may be more efficient but doubt you can readily buy such a device, and even if you could, it would be quite expensive.
In theory you could use the water to vaporize a low boiling point liquid such as pentane (which is used in geothermal power plants), to drive a small turbine and generator. The pentane would need to be in a closed loop, closed system with a evaporative water cooled condenser to recover the pentane. But, of course, that's a rather costly solution, given the small amount of heat available.
If you run the heat through your hot water system you can pretty much turn it's electricity off, saving you about 1/4 or more of your electricity bill. That's almost the same as generating electricity...
If you really want to convert heat to electricity you need something like an expensive high maintenance stirling engine. Converting heat->electricity cheap, quiet and efficient is one of those holy grails of energy research.