Pastel-coloured aluminium bottles of cleaning products can be purchased once and reused endlessly with UK startup Spruce's plastic-free dehydrated refills.

Spruce offers a more sustainable way of repurchasing its multi-purpose cleaning or bathroom spray. The startup has been shortlisted for sustainable design of the year at Dezeen Awards 2020.

The first purchase set comes with what Spruce calls an eternity bottle made of metal, and a trigger spray pump. Customers can then continue to use it with Spruce's plastic-free refills, saving them from continual purchases of cleaning products in plastic containers.

Refills arrive in sachets made of compostable material. To refill the bottle, the sachet contents are emptied into the bottle and mixed with tap water to create 500 millilitres of cleaning liquid. Spruce offers one-off refill packs of three or a recurring subscription service.

"For the compostable refill packs, we are using a paper material with a very thin layer of plant-based bioplastic, all from responsible sources," Spruce founder Mahira Kalim told Dezeen.

"The layer is very thin and completely free of petrochemicals."

Each packet can be cut up and added to the food waste or compost bin.

"It will decompose into biomass under ambient conditions within 14 weeks, as opposed to regular plastic bottles that live on for more than 500 years in our ecosystem," added Kalim.

Shipping powder rather than water is also better for the environment – it requires less energy as it is lighter to transport. The refill sachets weigh just four grams whereas a standard bottle of cleaning product weighs over 500 grams.

All the packaging and ingredients are sourced from within the European Union to keep the carbon footprint as low as possible.

Spruce's formulas are free of parabens, ammonia, chlorine and palm oil. Instead, the formula contains sodium coco-sulphate – the fatty acid from coconut oil – and essential oils such as eucalyptus and geranium leaf.

Kalim started Spruce after health issues made her look for an alternative to chemical home cleaning products.

"Whilst on my clean-living journey, I learnt about the grave plastic crisis our planet is facing," said Kalim.

"Not only are we polluting our oceans with single-use plastics, but our consumption habits have a direct impact on climate change," she added.

"Plastic overconsumption is not only an environmental hazard, in recent years the adverse health effects from consuming micro and nano-plastics have also become evident."

Of the 8.3 billion tonnes of virgin plastic ever produced in the world, a mere nine per cent has ever been recycled, according to a 2017 study.

Plastic is either incinerated or put into landfill, where it takes centuries to break down. Plastic waste ends up in rivers and then the ocean, where it harms marine life. As plastic erodes it turns into tiny particles that can enter the food chain and have negative health effects on animals and humans.

Designers are looking at ways of addressing issues with single-use plastic in the home. Design Academy Eindhoven graduate Mirjam de Bruijn created a range of waterless capsules that can be rehydrated to create detergent and dish soap.

In the USA, By Humankind is a startup brand making plastic-free toiletries such as refillable deodorant sticks and dehydrated mouthwash tablets.