I’m a user, I’m ashamed to admit. It’s not the ‘ick factor’, because as soon as you have a baby you get over all hang ups about that. No, reusables are just more work. I’ve not abandoned them completely because there are a lot of positives. But this isn’t an article that pits reusables against disposables; this is about accepting that people will continue to use disposable nappies and asking what we can do about the resultant waste.

With recent improvements in residual waste, recycling and food waste collections, we’re left with only a small amount of non-recyclable material. However, nappies fall into this category. And with the average child undergoing 4,000 nappy changes by the time they’re two and a half, how to deal with these is a pretty important question. Fortunately, there are a couple of companies out there trying to address the problem of not only nappies, but absorbent hygiene products (AHPs) – which include incontinence pads and female hygiene products that all contain fibre, plastic and super absorbent polymers (SAP) – in general. More than one million tonnes of AHP waste is generated a year here, nearly half of which is nappies with the ratio of fibre:plastic:SAP roughly 1:1:1.

Over in New Zealand, in 2007, nappies were a problem that was bothering parents Karen and Karl Upston. With two children in disposables and at the helm of a company selling nappies, they were fully aware of the waste they were creating. So, they decided to find out whether disposables could be composted – and not just those advertised as ‘compostable’, but your regular, everyday brands, too.

After being offered a HotRot Organic Solutions prototype composting unit for their trial, they started canvassing over 200 families to take part, along with six preschools, the local maternity hospital and care homes. Over the five-month trial, approximately 450,000 nappies were successfully composted, which equated to 56 tonnes of waste diverted from landfill.

Hailed a success, a fully operational HotRot in-vessel composter unit has since been set up with the ability to compost around 15,000 nappies per day, equating to five million nappies per year being diverted from landfill.

Once the AHPs are delivered to the facility, they are fed into the shredder. The shredded nappies are then mixed with green waste and are fed into a hopper and moved on to the HotRot composting unit itself, where the material is mixed up to 480 times over 16-20 days. The compost is then discharged and is stored for a further four to six weeks to mature prior to screening, when the plastic is removed.

The super absorbent materials are, apparently, great for composting because they enhance the moisture holding potential of the resultant compost, while the plastic is sent to energy-from-waste (EfW) plants as fuel.

In Christchurch, not only does the unit take AHPs from commercial outlets, but residents are offered a range of collection options, including weekly, fortnightly or casual collections. A weekly or fortnightly trial starter pack, which includes six bags, costs NZ$41.50 (£22). Sign up for a weekly, six-month collection, and the bags come down to NZ$5 (£2.50) each. What’s more, the Waimakariri and Kaikoura District Councils offer a NZ$1 (50p)/week subsidy for the first 26 weeks.

With the scheme in full swing, OCS, the international facilities services group, saw what a good thing the Upstons were onto and acquired Envirocomp in February 2011. Its subsidiary, Cannon Hygiene, collects 10,000 tonnes of AHP each year in the UK from a range of commercial premises and so was looking for a flexible alternative to landfill. OCS’s Andy Band explains: “The great thing about these plants is that they are scalable, multiples of HotRot in-vessel composting units.” He claims that in terms of cost, there’s very little economic saving, “because there’s a capital cost for the equipment. But, landfill is going up and then the economics become better.”

Envirocomp is opening another plant in Wellington in the next couple of months thanks to a grant from the New Zealand government and is working on projects in Australia and Europe. It is hoped that up to 10 local-solution plants will be built in the UK, according to Band: “We’re currently working with the Environment Agency looking at the licensing implications and anticipate opening a plant in the UK in the relatively near future. The first one will probably be in South East England.”

Meanwhile, Canadian company Knowaste has come up with another option to utilise the plastic. Knowaste’s first UK recycling plant for AHPs opened last September in West Bromwich, and is designed to process 36,000 tonnes of AHP waste annually.

AHPs are delivered to the West Brom plant for processing by commercial waste operators, including OCS/Cannon Hygiene, PHS All Clear and Rentokil Initial, which are charged a gate fee competitive to current landfill costs. The process then sees the waste fed into an autoclave, which breaks up the AHPs and sterilises them before pulping them. The material is washed and exposed to what is referred to by Knowaste as a ‘patented’ chemical treatment to ‘deactivate’ the superabsorbent polymers. After the moisture is released, plastics are removed, washed again, and then compressed into small pellets to make new products, such as roof tiles and fibre-based construction materials. Contaminants such as metals and glass fragments can be recycled and the organic/human solids are discharged to sewer for treatment at AD plants. According to Knowaste, 95 per cent of the material input is treated, with the rest being landfilled or sent to the sewer.

According to Roy Brown, CEO of Knowaste, the site marks the start of a £25 million investment in the UK “that will produce capacity for handling about a fifth of the AHP waste stream”.

But is this really a better disposal alternative, environmentally speaking? Last April, Knowaste commissioned a lifecycle assessment that compared its AHP recycling process with more usual disposal routes. Having considered the environmental impacts of disposing of one metric tonne of AHP waste to a combination of landfill (81 per cent) and incineration (19 per cent), advisory organisation Deloitte reported that: compared to the alternative, the Knowaste recycling process emits up to 71 per cent fewer carbon emissions. Based on an annual capacity of 36,000 metric tonnes of AHP waste (i.e. 32 Olympic swimming pools!), a UK Knowaste plant could save 22,536 metric tonnes of greenhouse gas emissions per year. That’s the equivalent, according to Deloitte, of removing 7,487 cars from UK roads.

Away from commercial collections, an idea that’s gaining momentum is that of kerbside collections of domestic AHP here, as in Christchurch. Knowaste’s Brown says they are developing partnerships with local authorities and OCS’s Band echoes the sentiment, but notes an obstacle: “We are seriously looking at this... but here it is collected as part of your council tax bill; in NZ it’s a separate charge.”

Local authorities that Resource has been in contact with seem enthusiastic about such a collection. Band asserts there have been few problems with acceptability in New Zealand and, in his opinion, storing nappies for a week is no different from food waste. However, he notes that while “a household with a new baby will be delighted to advertise the fact with a sack of nappies, an elderly relative using incontinence products might not be so keen on advertising that fact. So we need to look at methods that are preserving of people’s dignity.”

Indeed, Jonathan Straight, CEO of Straight, says he would be pleased to come up with a container solution for collecting nappies: “I imagine collection would be much like food waste although the contents would be heavier. It may be that a form of mechanical lifting would be used dependent on the weight. The container would also need to be odour proof and lockable.” In agreement with Band, Straight adds: “In order to avoid any stigma the container would need to look like something else – a food caddy or a wheeled bin, depending on the collection method.”

A quick survey of my net of mummy friends, and I was pleasantly surprised at how many would be willing to store up the nappies in a separate bin – after all, they are currently stored for two weeks in the residual bin anyway – and were even willing to pay for a separate collection, especially if it eased some of the disposable guilt!

It’s now over to the industry to get the ball rolling...