Sanitary Napkins and the Environmental Impact Part 5 – Methods for recycling disposable hygiene products

Sanitary Napkins and the Environmental Impact Part -5: Methods for Recycling disposable hygiene products

How to dispose a sanitary napkin? Have you heard of organic/ biodegradable/ compostable sanitary pads? Can sanitary napkins be 100% compostable? Can disposable products be recycled? What should be government’s policy around disposal of sanitary napkin waste?

This blog is a part of a series of 5 articles with the aim of answering some of the above questions and creating a complete picture of the life cycle of products to drive collective action towards better health and better environment.

  • In the previous articles, we have discussed about compostable material alternatives for sanitary napkins and other hygiene products. One of the biggest debates concerning plastic waste is whether to adapt to using compostable materials or to recycle materials post use.

    We have already looked at the challenges that we face while switching to compostable alternatives for materials used in sanitary napkins. We will look at various options for recycling plastic and initiatives taken by companies to recycle disposable hygiene waste. The following are a few methods which have been used to recycle diapers and other hygiene products:

    • Thermal pressure hydrolysis – Elsinga(Netherlands) In this process, the used products are collected in a tank, heated to about 250 degrees C and pressurized with steam to 40 bars. During the TPH process, the organic material in the reactors undergoes hydrolysis: its cellular tissue and long polymer chains are broken down under the influence of water, heat and pressure to its original smaller molecular components. Simultaneously, the plastic fraction of the input material melts. This fraction becomes a floating layer on top of the other fractions, and can be separated from the organic slurry. The plastics are sent to a granulation facility and are reused in new products. The organic slurry without plastic is treated further to generate bio-gas. When compared to Municipal waste incineration, this method has reduced the carbon foot print by 480kg per tonne of used products.
    • Refuse derived fuel (RDF) – PHS group(UK)Nagoya group(Japan)Unicharm(Japan): RDF is fuel derived from various types of wastes. It consists largely of combustible components of such waste, as non-recyclable plastics, paper etc. These fractions are separated by different processing steps, such as screening, air classification, ballistic separation, separation of ferrous and non ferrous materials, glass, stones and other foreign materials and shredding into a uniform grain size, or also pelletized in order to produce a homogeneous material which can be used as substitute for fossil fuels. PHS group generates RDF from used diapers.  It combines mechanical separation with chemical treatment and converts highly absorbent hygiene products into refused derived fuel (RDF), which is then supplied to the alternative energy market both in the UK and in Europe. RDF is typically burned in biomass plants to produce electricity and hot water either for municipal power systems, the National Grid or individual companies. Apart from generation of RDF from diapers, Unicharm overcame a major hurdle by creating a system that extracts high-quality pulp which is safe and reusable, by decomposing them with water, then sterilizing the byproduct with ozone. The system can recover several hundred kilograms of high-quality pulp from 4 tons of used diapers while emitting 30% less greenhouse gases than incineration.
  • Recycling pulp & plastics – P&G and Fater group(Italy): The technological process of recycling, developed from Fater patents, generates plastic granules and high quality and completely sterilized organic-cellulose material, using steam for eliminating all potential pathogens and odors. During the recycling process, diapers are sterilized, dried and separated into their basic components. These components include plastic, cellulose and super-absorbent polymer. From 1 ton of used products 75 kg. plastic and 225 kg. organic-cellulose material can be obtained.

By using and developing recycling methods, organizations are aiming to create a circular economy. A circular economy is an economic system aimed at eliminating waste and the continual use of resources. Circular systems employ reuse, sharing, repair, refurbishment, remanufacturing and recycling to create a close-loop system, minimizing the use of resource inputs and the creation of waste, pollution and carbon emissions. While installation of recycling plants might have a high initial capital investment, the carbon footprint in long term could be cost saving. Also the concept of circular economy ensures that requirement of new resources could reduce drastically for meeting the needs of end-users.

Whether recycling material from waste or using materials which are compostable, both alternatives have their challenges. But it is clear that both these methods are better than disposing waste into landfills or incinerating, which are the methods followed to dispose hygiene products (and other plastics) presently.

Segregation of products after use is a must requirement for both methods to work. Hence we need to invest in a robust infrastructure for segregation and collection of waste. It mandates that the end-users of products and waste collectors are very responsible while handling wastes. Also it is up to the policy makers to be decisive and bring up systems in place for recycling or composting (or both) waste and the manufacturers design products in a way which makes it easy to recycle. It requires a collective effort from manufacturers, consumers, policy makers and waste handlers to work together so that we can ensure that environment is protected while we meet hygiene product requirements for consumers.

Author: Kartik Mehta
CTO - Saral Designs

Kartik is a graduate of Engineering Design department of IIT-Madras and is the co-founder of Saral Design Solutions pvt ltd. He has designed and commercialized world’s first decentralized sanitary napkin manufacturing unit. He is a winner of the National Entrepreneurship Award 2016 by Ministry of Skill Development and Entrepreneurship, Winner of ASME ISHOW Global 2017 for hardware led social innovations, Winner of Outlook India Innovation 2019 award by BCH & EDANA for best innovation in personal hygiene industry in India.
Prior to co-founding Saral Designs, he had designed special purpose packaging machines, filed patents for two devices and has showcased his products in Brunel Design show, London. He has also been selected as one of the delegates approved by Dr. Shashi Tharoor to represent Indian contingent at Kairos Global Society, New York.

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