With the option of disposable diaper recycling at hand, the soiled nappy has never looked so good. The U.K.’s first facility for recycling dirty diapers and other absorbent hygiene products (AHP) was opened in West Bromwich in September 2011. Knowaste LLC. uses cutting-edge technology to recycle absorbent products such as disposable diapers, feminine hygiene, and adult incontinence products. The facility offers its solutions to local authorities, baby and childcare centers, hospitals and nursing homes, and washroom management companies.
The company is currently developing Knowaste at Hayes 180, an ambitious project located close to London. The site will handle at least 36,000 tons of AHP waste a year, according to the company. helping the area reduce waste and reach its ambitious aims.
In the U.S., the city of San Clarita has set up a trial diaper recycling program in California. However, one expert recently told the New York Times that the process is expensive, and would benefit from the creation of a product stewardship or recycling fee associated with AHP sales.
The Impact of Diaper Use
Recycling is usually not an opportunity for dirty diapers, which are considered to be garbage. With AHP already contributing two percent of the solid waste stream in Europe. Knowaste believes that AHP waste will continue to expand because of demographics and convenience, emphasizing increased usage for the young and old.
For example, a typical baby will use 6,000 disposable diapers before becoming toilet trained at two and a half years old, translating into over two tons of waste to be landfilled or incinerated. Around 15 billion disposable diapers are used annually in the U.S which translates into 2.4 million tons of waste. In Canada, approximately 1.5 billion disposable diapers are used.
A Growing Need
As life expectancy increases, usage of adult incontinence products can be expected to increase as well. At least 50 percent of nursing home residents in Canada and the U.S. suffer from incontinence, according to Knowaste.
The other key generation of AHP is from feminine hygiene products, which are used by 92 million women in the U.S and almost 10 million in Canada, collectively generating close to 1.4 million tonnes of waste annually. When disposable diapers, incontinent products, and feminine hygiene products are considered in aggregate, Knowaste sees a big opportunity for its technology to divert this waste stream and recycle it.
Success Indicators for AHP recycling
As in the case of recycling other materials, AHP recycling is most likely to succeed when it is supported by situational factors such as:
- High population density
- Emerging product stewardship mandates
- Government recycling incentives
- Landfill material bans
- Capacity concerns at the landfill, high fees
- High costs of incineration
- Heightened air quality regulations
- Adequate feedstock (Knowaste’s previous plant in Europe at Arnhem in The Netherlands was forced to close due to issues with sourcing feedstock. It says it will not face similar problems in the U.K.)
AHP Sourcing and Recycling
Sourcing of AHP feedstock is not anticipated to be an issue with the launch of the new plant. It is being drawn from a number of commercial AHP waste operators that collect material from washrooms, hospitals, nursing homes, and care nurseries. These providers are charged a rate that is competitive with the cost of dumping material at the landfill.
As for recycling, the challenge for AHP products is in the material mix. Both disposable diapers and adult incontinence products encompass several components, including mixed plastic in outer and inner layers, wood pulp cushion, and superabsorbent polymers.
AHP is first sent to an autoclave, where the material is broken apart and sterilized. Next, comes washing, and exposure to a special chemical treatment that deactivates the superabsorbent polymers. With the completion of this washing process, the plastic materials are removed and sent to a separate device for processing.
Plastic components are once more filtered and cleaned in a second washing cycle, before being compressed into small pellets for resale. The residual AHP material enters a screening process where any remaining traces of plastic and other organic material are captured and separated from the fiber. Water is recaptured from each wash cycle during the recycling process. It is sent through a clarification system after each wash and then reused in the Knowaste system.