United Flight Turns Back to Frankfurt After Toilet Malfunction Spills Waste in Cabin

United Flight 59 from Frankfurt to San Francisco had to turn around after toilet contents spilled into the cabin
The overflow happened a couple hours into the flight when at least one toilet tank broke
The plane circled over the North Sea as crew tried resolving issue before returning to Frankfurt
Passengers were rebooked on flights the next day and offered hotel rooms for the night
United has had several recent incidents, including a diverted flight over winds and a plane losing a wheel during takeoff