Views: 0 Author: Site Editor Publish Time: 2022-04-11 Origin: Site
To date, diaper waste has been incinerated directly for energy recovery or converted to RDF, which is used in industry to generate heat. Biodegradable diaper waste is usually disposed of in anaerobic landfills, which, to most people's surprise, are no more environmentally friendly than incineration, especially if the landfill is not equipped with a methane gas recovery system or if the diapers are not completely dry by daylight for recyclable materials and require pre-treatment with centrifuges and dryers.
In addition, the industry has, for example, Knowaste and Terra Cycle, experimenting with new technologies for recycling diapers that are not inherently economically sustainable and do not have sufficient case studies to demonstrate that these technology models can be replicated across the globe. Despite the fact that some of these technologies have been rolled out for decades, investors remain skeptical of the business models for these technologies.
The fact is that despite growing consumer concerns about the environment, most post-use diapers are still being disposed of in landfills. Clearly, millennial consumers who are becoming parents are not satisfied with the industry's current solution to reduce the environmental impact of diapers. Because burning diapers produces carbon dioxide (a greenhouse gas), consumers do not have a positive view of this. Some companies are working to develop new technologies to properly dispose of the greenhouse gases produced by incineration, but for now, incineration is not going to be the ideal solution any time soon.
Millennial consumers who become parents are not satisfied with the solutions the industry is currently adopting to reduce the environmental impact of diapers.
Two and a half years ago, the two companies began leaking information about their ongoing projects and presented their solutions for recycling waste diapers on social media platforms. They are currently making technical presentations to potential customers around the world and presenting papers at global diaper industry conferences. The prototype plant that has adopted the diaper waste recycling solution is located in Treviso, Italy and is operated by P&G-Fater. The process starts with raw material separation using a rotary autoclave and screens (if interested, you can watch some videos about the plant online); the waste is recovered using hydrogen production from biomass in diaper waste and ozone bleaching to recover the pulp, as proposed by Unicharm. There are also other companies promoting attempts and efforts in diaper recycling, including Kimberly-Clark's partnership with Envirocorp in New Zealand and Essity's partnership with Renewi in Europe. All of these projects are now trying to prove to the world that they will ultimately get the best, most economical or ecologically valuable solution for diaper waste, and hope to be leaders in this field.
However exciting these projects may be, there is still a particular paradox that is rarely mentioned. Traditional diaper recycling requires the separation of all plastic components (such as polyethylene and polypropylene) into pellets that can then be used in other industries, such as plastic injection molding. In order to work in the most efficient way, they need to provide the equipment with a high purity of the recovered plastic material, other impurities may compromise the quality of the recovered material or require additional separation processes.
And it's not that simple. In today's market, an emerging group of consumers tend to avoid exposing their babies' skin to synthetic materials, preferring natural material alternatives instead. These consumers want diapers made from natural ingredients of plant origin, such as starch-based films, PLA (polylactic acid), viscose fibers (made from raw materials such as bamboo, pine or eucalyptus), and biodegradable SAP. cotton into nonwoven materials for top or bottom layers is not a major problem in terms of recycling, as cotton can be extracted and blended with cellulose The addition of hydrophobic cotton to surface or substrate nonwoven materials is not a major problem in terms of recycling because cotton can be extracted and blended with cellulose as a single product. However, blending natural component film materials or plant-based plastics with synthetic materials can complicate the material composition and make the recycling process more difficult. The problem is that we need to separate products using plant-based materials from those made from synthetic materials in order to make the waste recycling process more efficient. This brings up a new question:How do we organize the diaper waste collection process to avoid mixing different types of diapers together.
A well-known solution for disposing of diaper waste from plant-based materials is composting. However, this process cannot be carried out by consumers who install composting facilities in their own gardens because most plant-based materials, such as PLA or other plant-based plastics used in diapers, require at least 60°C to begin decomposing for composting, which is beyond the capabilities of small composting facilities. In addition, air needs to be pumped in to avoid the production of methane gas, which is tens of times more harmful to the environment than carbon dioxide. The proper treatment of such diapers should be managed as an aerobic composting solution using an industrial composting facility. In this process, plant-based diapers are mixed with other biodegradable materials and composted in an industrial plant at a constant air environment and at temperatures above 60°C. At the end of the composting cycle, filters are used to remove all uncomposted minor components such as elastomers, hot-melt adhesives, and some other materials that may be smaller in volume compared to the resulting compost. For the use of bio-SAP materials or the use of potassium-based synthetic polyacrylates (similar to the original SAP sold in the mid-1980s) instead of sodium polyacrylate, SAP can be recovered and used in the final compost pile. For Na-SAP it is necessary to consider whether the percentage used is low enough to avoid an increase in soil salinity. For safer use in agriculture, the use of K-SAP instead of Na-SAP can avoid excessive salinity that can kill plants that use composted soil. Finding a biodegradable SAP (such as the new feedstock currently being developed by companies like The-tis or Ecovia) or a good synthetic K-SAP alternative (compatible with agriculture) is less complicated than a total diaper recycling solution. Of course, any recycling process that requires autoclaves to work "in batches" will not be as efficient as continuous operation either.
With plant-based material diapers, we face the same problem as with synthetic fibers. If a diaper is made entirely of synthetic ingredients, but recycled and mixed with input plant-based materials for composting, it will never compost and will even contaminate the composting process. At a minimum, the bottom layer of the diaper needs to be compostable so that it can break down and expose the organic components inside the diaper to compost.
In conclusion, the quest for recyclable solutions for diapers needs to develop both of these conflicting paths in order to provide consumers with more choices, whether they prefer to use recyclable synthetic materials or natural plant-based materials. Both options need to have a good waste disposal solution. Another key issue is that they share the same bottleneck: the need for efficient collection processes to recycle synthetic materials from diaper waste or to compost them industrially accordingly.
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