By Mike McKimm BBC Northern Ireland environment correspondent

About 40,000 tons of them are dumped in landfill in Northern Ireland every year. That is 100 tons every day.

It is 4% of the total waste going to landfill. If there is a baby in your family its one third of the contents of your bin.

Disposable nappies - some call them the convenient ecological curse of the 21st century.

To try to head off the ever growing mountains of sodden plastic covered tissue and chemicals heading to the waste dumps, the Women's Environmental Network have launched their annual campaign - Real Nappy Week.

Its core objective is to encourage new mums to switch back to the good old reliable cotton or Terries nappy.

The big drawback with these devices over the disposable ones, is the cleaning up.

Healthier

The reusable nappies are actually healthier for society as all the liquid and solids go into the sewers and are treated properly.

But the washing, drying and even putting them on is more than most modern mums want to cope with.

The disposable nappy is an easy fit, remove and forget task. Most even come with a scented plastic bag to allow easy disposal - into the bin.

They then make their way to the local landfill site where they will be covered over within hours and remain intact for decades, probably centuries.

The content is also available for birds and flies and can leak into nearby groundwater. Its not what landfill was designed for - thousands of tons of human waste.

Nappy laundry

The reusable nappy market has seen great strides.

Modern cloth nappies are now shaped for easy use, have biodegradable liners and Velcro fasteners. But they still need to be washed and dried.

In England and Wales, a regular specialised laundry service makes this a viable proposition for the working mother.

There are no such facilities in Northern Ireland, and the once familiar sight of rows of white, freshly scraped and washed, cloth nappies waving in the breeze is rare these days.

However, the disposables' days could be partly numbered.

A dramatic clamp down on landfill is already creating major problems in Northern Ireland.

Target

To meet European legislation, there has to be an equally dramatic drop in the amount put into the household bin - and nappies could soon be targeted by the powers-that-be.

It may only be a vain campaign to encourage mothers to change their habits or it could be a bin tax of some sort.

But something has to be done to curb the sheer bulk and unsanitary arrangements we currently indulge in.

As local councils have to pay more and more to dispose of domestic waste, it may even be cheaper for them to start up a nappy laundry to encourage a move back to the humble reusable cloth device.

Biodegradable

There is another option - totally biodegradable nappies. They almost exist but current versions still have a few bits of plastic attached.

But they use no bleach and are filled with wood pulp instead of mysterious chemicals. The idea is that councils set up special composting sites for these nappies.

However, it is an idea that has not quite caught on yet.

Given the pace of change when it comes to waste management in Northern Ireland, it could take another generation of nappy wearers before it's all in place.