According to WIRED, who wrote according to The Record, 16-year-old Daniel Burd did it in that time, compared to the thousands of years usually necessary.
Kudos to him for a great solution to a huge environmental problem. I love the base of the entire solution: Tap Water, Yeast, and Dirt, in which ground plastic apparently decomposes (but if you read further in The Record article, it apparently took some separation of the key microbes to get the right one).