Festival goers on day 1 of the V Festival at Hylands Park

Festival goers on day 1 of the V Festival at Hylands Park on August 17, 2013 in Chelmsford, England. 

Rob Harrison/Getty Images

These days, there are more music festivals than ever, but organizing these events still presents unique challenges. Billboard breaks down four of the toughest problems facing music festivals.

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GoTenna, a Brooklyn startup, sells pocket-sized wands ($149 a pair) that, by connecting to cellphones with Bluetooth technology, communicate in dead zones. Users can't scroll Twitter and Facebook, but they can complete emergency actions, like sending texts and exchanging GPS coordinates.

By offering only compostable food items, Bonnaroo diverted 366 tons of waste from Tennessee landfills in 2014. Central California's Lightning in a Bottle offers free water stations in lieu of selling disposable bottles. "A lot of festivals get complacent," says Lightning in a Bottle co-founder Dede Flemming. "They book a big lineup, sell a bunch of tickets and forget about the attendees and the grounds. It's short-sighted."

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Can the look of a crowd affect its behavior? Some event organizers think so. In 2014, a handful of festivals banned rave paraphernalia (like glow sticks), and in 2015, Ultra Music Festival, which draws more than 150,000 to Miami, will prohibit nontransparent bags, pacifiers, stuffed animals, totems and masks.

Access Event Solutions, a Nevada ticketing-and-credentials tech company, makes RFID and NFC wristbands that can grant different backstage access levels for VIPs, artist managers and press. Programmed with the wearer's name, each band can be easily updated if the owner has been ejected.

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This story originally appeared in the April 4th issue of Billboard.