In all honesty, I don't think you really need to put in a huge effort for this one, it seems like they just want relatively low ground and water pollution. I wasn't actively trying for the achievement, though strangely enough when it popped I was actively going for the 5 full garbage dumps achievement.
-The power source I used was turbines and water turbines.
-I had the outflows placed on the very edge of the map so they left the map quickly
-I had industry, as well as farm and forest specialized industry (so the industry is probably air pollution)
-I had 1 full garbage dump turned off (to save budget) as well as 4 partially full ones all in the same area.
-I did not have an incinerator, so I don't think that makes much difference
If it helps any, the map I was using was islands. I originally had my outflow sewage on the farthest I could go on the bottom right of the starting square (3,3) if you look at the map with the grid at the following page. After buying more land, I moved them to the lowest water between the two little islands (so on square (4,4), the corner of the small island in the bottom right of that square) http://www.skylinesplanningguide.com/2015/03/CitiesSkylinesM...