In Arizona, a compostable diaper company has launched a subscription service to send clean diapers to parents and receive return shipments of the used nappies for composting.   Dyper, which calls the service ReDyper, has partnered with TerraCyle, a recycling and composting company, to make the model work.  First, Dyper will ship parents its bamboo-based diapers directly. After use, parents can mail the diaper back in prepaid packing materials compliant with the United Nation’s hazmat specifications. The dirty diapers are converted by TerraCyle into compost for landscaping, particularly for municipal use.   “It’s got to be super convenient. It’s got to be, frankly, as close to convenient as possible relative to throwing it out,” TerraCycle CEO Tom Szaky, tells Fast Company. The diaper service costs $68 for 260 diapers, shipping included. If the parents don’t have access to composting facilities, the option to return the dirty diapers costs an additional $39.   Over 3 million tons of dirty diapers end up in landfills annually, and most take as much as 500 years to biodegrade.