Wally's Wastewater Treatment Plant

I've seen kids make some amazing things with Lego, but I've never seen a wastewater treatment plant, nor one built by such an impressive 4 year old!

 
Update: Click here to see the video at YouTube where you can view it full screen. I realize that the right side of this video is cut off the way I embedded it on this site.  

(Hat tip to Kari Stuart for posting this first on the Wastewater Professionals forum on LinkedIn.)