Research pick: Diaper disposal? It’s a dung deal! - "Effectiveness of cow dung and effective microorganisms on composting of napkins and diapers"

Research in the International Journal of Environment and Waste Management has looked at how used diapers (baby nappies or adult napkins) and sanitary wear might be efficiently composted using cow dung a readily available by-product of cattle farming the world over.

Namasivayam Vasudevan, Greeshma Odukkathil, and Gomathi Ravi of the Centre for Environmental Studies at Anna University in Chennai, Tamilnadu, India, explain how absorbent hygiene products (AHPs) including diapers and sanitary wear are now ubiquitous in the developing and developed world having broadly displaced the washable and reusable alternatives. As such, they represent a growing waste disposal problem.

AHPs are generally not biodegradable unless somehow pre-processed nor easily recyclable, not least because of the waste they carry with them. They generally accumulate on rubbish dumps and in landfill in regions where such waste is not burnt. More than 250 tonnes of such waste enters the waste stream in Chennai alone each year, the team writes.

The team has looked at cow dung and effective microbes that might be able to break down used diapers and sanitary pads. They tested the putative composting process over a sixty-day period, recording chemical and physical changes in pH, moisture content, carbon-to-nitrogen ratio, and nutrient levels.

The team suggests that their results are somewhat promising. The compost derived from AHPs exhibited favourable characteristics, including a neutral pH, optimal moisture content, and suitable nutrient levels. There was, in addition, a significant drop in overall volume and mass, ranging from 70% to 85% during composting. This latter point suggests that the composted AHPs would if ultimately destined for landfill at least take up less volume in the site if processed in this way first. The chemical changes induced by composting would not necessarily make them useful as soil conditioner in other similar applications, but at least the processed materials would be somewhat less polluting. However, with further optimisation, it may well be possible to process used AHPs into a usable compost for an overall more ecologically conscious approach to their disposal.

Vasudevan, N., Odukkathil, G. and Ravi, G. (2024) ‘Effectiveness of cow dung and effective microorganisms on composting of napkins and diapers‘, Int. J. Environment and Waste Management, Vol. 33, No. 4, pp.511-523.