SUSTAINABILITY AND THE ENVIRONMENT: WASTEWATER
Humans are creatures of waste.
Disposing of what we produce,
naturally and industrially,
has always challenged us;
the lazy side of human nature needs to be
shepherded into clean routines by etiquette,
laws or civil infrastructure. Before the advent
of sewerage systems, for example, night soil
was tipped into the street without a second
thought.
Consequently, the science of waste
disposal straddles psychology as much as
civil engineering, and today this science also
encompasses the new imperative to make
all human activity more environmentally
sustainable.
One of the educational resources that
environmental technologists like Professor
John Williams tap into is curiosity: just
exactly where does the plughole lead?
Professor Williams recounts the time he
took students to a wastewater treatment
works, where stage one is the screening-out
of solid rubbish. Curiosity knows no limits
when it comes to our waste and where it
goes: “What’s the worst thing you’ve found
on the screens?” asked one student.
“Fingers,” the Process Scientist guiding
the tour replied.
As Professor of Environmental
Technology at the University of Portsmouth,
John Williams’s research focuses on water
engineering, with a particular emphasis on
water quality, and this means doing a lot
of work on understanding how wastewater
systems are misused by people.
The discovery of fatbergs that build up
and block sewers came from this research.
Fatbergs develop when fats, oils and
greases from domestic and commercial
kitchens are poured into the sewage
system. They react with calcium and other
ions that are present in sewage and create
a form of heavy soap – but not one you
would choose to wash with.
“People put all kinds of things down
the drain which they shouldn’t,” Professor
Williams observes. “It’s our flush-and-forget
mentality.
“People don’t consider what the
infrastructure is for and how they connect
with the environment through this
infrastructure.”
He says a particular challenge is harmful
materials too small to see, let alone screen.
These include traces of pharmaceuticals
in urine, and microplastics – tiny synthetic
fibres that are stripped from clothing in the
turbulence of washing machines and drain
away with the dirty water.
A Portsmouth PhD student, Serena
Cunsolo, is working on a nationwide
project to develop ways of finding out what
happens to these microplastics during
sewage treatment, and where they finish
in the environment. As with all micropollutants
there are serious concerns about
how much is consumed by fish.
Professor Williams says breaking through
the public awareness barrier is key to reducing
this risk: “If people can relate to what they’re
doing in the kitchen and, for example, start
pouring fat into a container instead of down
the drain, that’s a step forward.”
To facilitate this, the University of
Portsmouth has laboratories at a sewage
treatment plant. This enables researchers
to run pilot trials using real sewage, create
large datasets and analyse samples in
on-site laboratories.
The power of reeds
Professor Williams is a world authority on
the development of low-impact, sustainable
technologies to deal with dirty habits,
including contaminated landscapes.
In Egypt, South America and the UK,
he has worked with constructed wetlands,
using reed beds to treat polluted water. This
is a natural process ideal for locations or
economies for which large-scale mechanical
and chemical processes are not practical or
affordable.
“Reed beds have application where there
is no infrastructure to support processes
that are energy and mechanically intensive.”
He says reed beds are ideal for
‘environmental engineering’ because reeds
have a mechanism to transfer oxygen from
their leaves to their roots. Root zones
modified in this way become intensive sites
of microbial activity: “If you plant reeds
in a swamp which has no oxygen in it,
the reed roots will become oxidised, and
that promotes the breakdown of organic
compounds.”
Reeds can grow under flooded conditions
or hydroponically in gravel, making them
ideal for healing contaminated sites.
“We’ve had reeds growing in what we
believe are UK-record levels of petroleum
hydrocarbon pollution in sediment, with the
reeds still growing happily and cleaning up the
sediment by stimulating microbial activity.”
Understanding and acceptance
Professor Williams recognises that making
change happen is, in many ways, a
challenge of psychology.
“In lower-income countries,” he
observes, “people have a greater
connection with the environment, because
they’re using its resources more directly.
“Whereas in the UK, there’s a barrier.
People have switched off from the idea of
needing to live with water because there’s
a sense that it’s fully managed … that, for
example, you can build in a low-lying area
because we have drainage schemes that
pipe the water away. But that’s just another
example of relocating the problem.”
Professor Williams uses this example
to offer a more sustainable alternative for
housing developments in such areas: adding
wetlands and ponds into which water can
drain naturally.
He points out multiple benefits: “As well
as flood control, you’ve got water quality
improvement as it passes through the
wetlands, improving river water quality and
downstream habitats.
“Also, I’ve found people like having
habitat within a housing development.
Having green space encourages people to
be more active. It also improves air quality
– the benefits can go on and on and on.
“Yet some resist the idea because the
presence of ponds or wetlands lead to
assumptions that natural water bodies pose
a flood risk; people don’t realise that their
presence actually makes such an event less
likely,” he says.
“So sustainability solutions for fitting
housing to natural landscapes, or for
wastewater generally, need psychology
as well as science and civil engineering.
We need people to understand that the
plughole is not the end of the matter … it’s
just the beginning.”
ISSUE 1 / 2020
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