War on waste makes sustainable business more profitable
Every week in Lagos, Nigeria, a fleet of cargo bicycles goes round people's homes picking up plastics, cans and sachets.
The residents receive points based on the weight of recyclables they collect, which they can redeem for basic food items, consumer electronics, or cash.
This is the low-tech, but high impact, recycling scheme run by WeCyclers - a new breed of social entrepreneur making sustainability pay.
The company, which works in partnership with the Lagos Waste Management Authority, makes its money by selling the materials on to manufacturers.
"The plastic gets shredded and exported to make polyester fibre for clothing or pillow stuffing," says WeCyclers chief executive, Bilikiss Adebiyi-Abiola.
"It is really making a difference at street level," she says. "There is less pollution and less flooding. People say their neighbourhoods are cleaner and their kids seem healthier."
More than 5,000 households have signed up so far and there are plans to extend the scheme to other cities throughout Nigeria.
A similar scheme giving people a financial incentive to recycle waste is Canadian social enterprise Plastic Bank.
Speaking to the BBC from Greece, where he has been admiring the country's white beaches and blue seas, co-founder David Katz says he has always "felt a connection at the water's edge".
The degradation of the world's oceans caused by the dumping of plastic has long irked him, as has the widespread poverty he witnessed on his travels around the globe.
Business, he realised one day, could be the way forward.
"Pound-for-pound," Mr Katz explains, "plastic is more valuable than steel."
Starting in Colombia and Peru, Plastic Bank is setting up repurposing and exchange centres that offer incentives to locals for gathering and sorting recyclable plastic waste.
In return for a quantity of the material, contributors are offered credits for a range of basic products.
But it's a technical innovation which is helping to drive the social enterprise.
In a collaborative project with the University of British Columbia, Plastic Bank is working on a machine that transforms waste plastic into filament that can be a source material for 3D printers.
The plan is to use these printers to allow Plastic Bank members to mould everyday products, such as household utensils and educational toys, from the plastic they collect.
One day, the printers could even make water pumps and other vital tools, Mr Katz envisages.
But while WeCyclers, Plastic Bank and others focus on repurposing waste, some businesses are using technology to reduce the amount of discarded materials entering the ecosystem in the first place.
For example, Unilever, one of the world's largest product companies, is trialling a new type of plastic bottle that incorporates air bubbles "like an Aero bar", says Karen Hamilton, the company's vice-president of sustainable business.
The MuCell technology uses gas-injection to create bubbles in the middle layer of the bottle wall, thus reducing the density of the product and the amount of material required by 15%.
The company estimates this will save 275 tonnes of plastic in the first year.
In 2015, Ms Hamilton says Unilever will be making the technology available to all - including its rivals.
In another example, Unilever's 25% smaller aerosol deodorant can, developed using new compression technology, will save enough aluminium to manufacture 38,000 bicycles, the company claims.
This is a far cry from 15 years ago, when the company's attempt to sell concentrated laundry detergent in smaller bottles failed miserably.
Its attempt to reduce waste was shunned by consumers, worried that they were getting less value for money.
However, consumers have become more aware of sustainability issues in the interim.
Cutting your cloth
Another company employing technology to reduce waste is wear2, a Chester-based firm bringing "ecostitching" to the rag trade.
Together with the University of Leeds, it developed a novel fibre for sewing clothing seams, which can be easily unpicked when exposed to microwave radiation - leaving no trace on the original material.
Using this technology, clothing manufacturers can choose which parts of a garment they would like to disassemble in the future, and repurpose old material easily on an industrial scale.
This is especially useful for branded corporate clothing, which is sometimes thrown away en masse when a company changes its logo, or colour scheme.
Charlie Rea, a project manager at C-Tech Innovation, one of the organisations behind wear2, says the project is "creating a revenue stream, rather than a waste stream".
He may have hit upon the crucial ingredient driving the success of sustainability-focused firms - linking sustainability to profitability.
Matt Loose, of think-tank and business consultancy SustainAbility, which advises global corporations such as Nike, Starbucks and Shell, believes this is what gives a good idea legs.
"We give a very strong message to our clients that there has to be a really strong business case, and not just goodwill," he explains.
In addition, some argue that disparate enterprises must share ideas and develop solutions together if sustainable ideas are to become profitable.
For example, the Ellen MacCarthur Foundation, set up by the eponymous sailor famous for being the fastest person to circumnavigate the globe, is building a collaborative environment where some of the world's largest companies, such as Apple, Ikea, Coca-Cola and H&M, address their concerns alongside geeks, innovators and other organisations.
Sustainability, according to such advocates, is about caring and sharing. But it is also a prime business imperative.
As Plastic Bank's David Katz puts it, these days companies have to exhibit environmental responsibility "just to be able to compete".