foaming blue Lipo?

I had a Flight Power 4s Lipo go bad literally in my hands. I got this adapter from Cheap Battery Packs so I coud use a Hyperion Balance to balance my Flight Power packs. I'm not really sure what went wrong, but when I pluged it in it started smoking. It happed so quick it burned my fingers where I was holding it on the wire. First thing I could think of was to grab the balancer and run for the sliding glass door that leads to outside. As soon as I did that the lipo disconnected and dropped on the carpet with the wire still on fire. I was able to grab it and throw it the rest of the way outside. The tiny fire died out pretty quickly after that.

The pack was shinged on the inside. The tap wires were half there and half gone. After I got the smoke out of the house I thew it in some salt water. That was Yesterday. Today there is a bunch of foamy looking blue stuff in the water.

What I would like to know is how can I get rid of this water now? Is it safe just to dig a small hole and dump it in the back yard? Or, pour it down the drain? Or, something else? Anybody know?