Page 89 - BBC Focus - August 2017

HOW IT WORKS

MR TRASH WHEEL

At the mouth of the Jones Falls River, where it feeds into Baltimore Harbour in the US, sits Mr Trash Wheel. Since 2014, this semi-autonomous floating
rubbish collector has scooped up more than 500 tonnes of detritus, including 9,000,000 cigarette butts, 492,000 coffee cups and 376,000 crisp packets. ff
Mr Trash Wheel cost $720,000 (£560,000) to build, and has now been joined by Professor Trash Wheel, a ‘female’ version in a different part of the harbour.ffj

2 2
The conveyors are
powered by a water
wheel fed by the
river current. When 4
the flow isn’t fast As each skip fills,
enough, solar panels it’s towed away and
3 can take over. the rubbish is
incinerated
A second convveyor to generate
belt scoopps electricity.
up the rubbish,
drains awayy the
water and carries
the rest into aa skip
on a separaate
floating barrge.

1
5
The river current
drives trash toward Most of the rubbish
floating booms, isn’t thrown in the
which funnel river directly – it’s
rubbish to Mr Trash land litter, washed
Wheel’s mouth. in by the rain.
Long forks attached A heavy storm can
to a conveyor fill 12 skips!
collect and compact
the debris.

QUESTION OF THE MONTH

WINNER!
Do all fish and shellfish
contain mercury? Jack Moore wins a pair of
Groove-e
ve-e’s new Action Earphones ’s n
JACK MOORE, FROME
ov-e.co.uk). Held ink
(£44.99,groov-e.co
position around you
our neck with a
kband, the stylish
Mercury levels in the oceans have bright LED neckb
s are designed to
tripled since the Industrial Revolution, earphones
thanks to mining and the burning of make yo ou stand out and
fossil fuels. All sea creatures absorb be s seen, improving e
some of this heavy metal directly, and safe ety for runnerst
at night.
once it’s in the body there’s no way of a
getting rid of it. The amount of mercury
in fish varies between species. Long-
lived predators like tuna and swordfish
tend to contain the most, because they
also absorb mercury from their prey and NE
NEXT ISSUE:
they’ve had a long time to accumulate
it. The lowest levels are found in short- Can birds fly upside-down?
lived species lower down the food chain,
What causes eczema?
such as oysters and shrimp. HS
Do dogs have a concept of time?
Email your questions to questions@sciencefocus.com or submit online at sciencefocus.com/qanda

89
89