Sanitary napkins: Why biodegradable is not the same as compostable

The way Indians think about menstruation has shifted in recent years. The regulations, guidelines, waste management practices, as well as menstruation products, are continually being updated to serve women better.

Many women opt for menstruation cups and reusable cotton pads, which have little or no environmental impact. Several have begun to choose ‘biodegradable’ sanitary napkins. However, there has been some debate regarding how sustainable these biodegradable napkins are.

It is essential to understand why any disposable sanitary napkin can be harmful to the environment. One should consider the carbon emissions generated during the manufacturing process of a sanitary napkin and its active lifespan, apart from waste generation, treatment and disposal techniques.

When we use a reusable product, however, we may optimise the value of the emissions by utilising it for an extended period due to its prolonged active lifespan. We produce less trash, emit less carbon dioxide, and spend less on products such as menstruation cups, reusable cloth pads and period panties.

Reusable menstrual cups and cotton napkins have a longer life span than disposable sanitary napkins, which directly affects the quantum of waste these products generate over time. 

Current alternative sanitary products and their longevity

Source: WaterAid and MHAI (Menstrual Hygiene Alliance of India)

We also must understand that biodegradable is not the same as compostable. While all compostable material is biodegradable, not all biodegradable material is compostable.

Although biodegradable materials return to nature and gradually disappear completely, they can sometimes leave residues. On the other hand, compostable materials produce compost, which is rich in nutrients and beneficial to plants.

Compostable materials are biodegradable with the extra benefit of being composted. That is, as they decompose, they release vital nutrients into the soil, which helps plant growth.

Most of these ‘biodegradable’ pads claim to be chemical-free and compostable. Many biodegradable pads eliminate super-absorbent polymer (SAP) and wood pulp, but some plastic is retained for waterproofing.

How is it better than disposable napkins if the biodegradable, organic-tagged pads have bleached white cotton and plastic liners?

It wouldn’t be incorrect to say that these ‘biodegradable’ sanitary napkins are not entirely compostable. The term can also be misleading.

In a study conducted by the organisation Green the Red, a few sanitary napkins labelled eco-friendly and compostable were composted. The results were as below:

Sanitary napkin sample 1: These pads were not bleached and were made of banana fibre. Two pads were composted, one used and the other unused.

At a high room temperature, the one with blood dissolved and composted in 7.5 months, whereas the one without blood took 5.5 months to compost. This is how the napkin looked after two and six months in compost:

                                                                         Source: Green the Red

Sanitary napkin sample 2: This pad appeared to be bleached white. A used pad took more than six months to dissolve on composting. It had a non-shredding plastic coating.

It was finally removed from the compost pile. Napkin after two and six months in compost is shown below.

Source: Green the Red

The results suggest that these sanitary napkins may be biodegradable, which may degrade in years due to some amount of plastic coating, but they are not compostable.

However, it remains unclear whether they are genuinely eco-friendly and sustainable options. The components used to make the napkin determine whether it is a green napkin or a regular napkin.

Perforated polyethene or non-woven polypropylene used as the top sheet is frequently mistaken for cotton due to its texture and appearance. It is, however, non-compostable.

In addition, the polyethene back layer and the top layer together make up about 25-30 per cent of the total weight of a sanitary napkin.

The non-compostable materials are typically utilised for the top permeable layer, usually non-woven, the barrier plastic layer used underneath, super-absorbent polymer (SAP), and the hot-melt glue in sanitary pads. Apart from the glue, which is utilised in small amounts, the remaining components must be replaced.

Extended producer responsibility, therefore, must be integrated into the system. Manufacturers of sanitary products must be held accountable for the waste generated by their products.

For the it to be environment-friendly, the compostable napkin must be designed with only plant-based compostable materials such as bamboo and fibres or corn starch, etc.

The napkins labelled biodegradable should be ISO 17088:2021-certified from government-authorised testing facilities, which outlines the procedures and requirements for identifying and labelling products made of plastics appropriate for aerobic composting.

Consumers must also be conscious of what they are purchasing. Instead of looking for the term ‘biodegradable’, look for the term ‘compostable’. A compostable pad usually takes 90 to 180 days to decompose.

Compostable napkins can decompose in the soil within the specified time frame, producing no harm to the environment. Biodegradable or oxo-degradable sanitary pads are usually confused with fully compostable sanitary pads.

The lack of education across levels contributes to the stigma and lack of awareness of sanitary waste management. The administration is often unaware of the science behind them and their disposal.

One of our long-term priorities in India should be information, communication and education (IEC) and capacity building to raise awareness about more environmentally friendly products and their disposal practices.

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