Before you can get rid of the odor, you have to eliminate the source. You got rid of the leak, now you have to find the remnants of what it caused. If you haven't already, you'll need to completely empty the basement of everything stored. Anything that's soft will need to be cleaned and likely soaked in a 1:10 bleach:water solution to kill the odor causing bacteria. You might also have some insulation in between the floor space that was affected and needs to be removed/replaced. If there is a wood floor, it may also have been soaked and growing stinky bacteria so that needs to get a shot of the bleach solution too. There are lots of places where the leak could have gone and caused the problem. Until you find all of the spots and get rid of them or treat them, you will always have the odor.
How do I know? I used to work for a school maintenance department. One summer we had a walk-in freezer that took a dump and was full of hamburger. It sat, un-checked for 2 months while all that meat rotted. I have been in Emergency Services now for the past 26 years and have seen and smelled some pretty awful things in my time. That freezer, to this day, takes the prize for the worst smell I've ever experienced. We removed all the meat...pressure washed the interior of the freezer...removed all wooden racks...sprayed with 1:10 bleach:water solution...let soak for 2 days...pressure washed again...sprayed with an enzyme product and finally after about 2 weeks, the freezer was able to be used again.