Integrated water management
South Africa would benefit from a renewed focus on the quality of
water being discharged into our rivers.
By Manda Hinsch
I
t is important to take an integrated
approach to our water quality
management. If we do not pay enough
attention to what is being pumped into
our rivers, it makes it far more difficult
for the authorities to treat water to
potable standards — and the costs
associated with that treatment will of
course also increase, making potable
water more expensive.
Where the water source contains
organics, for example, a tertiary phase
sometimes must be added to the
treatment process, using a technology
like activated carbon to help improve
the quality of the water. This solution
raises the costs substantially, though.
It is so expensive that authorities tend
only to use it sporadically and only
under severe conditions.
The focus really needs to be on the
source of the pollution; for instance,
where industries are externalising their
costs by not treating their discharge
to the required level of quality. The
cost then ends up being footed by the
users of the water treatment works
downstream.
While South Africa has its SANS241-1
(2015) standard — which is based on
the World Health Organisation’s potable
water standard — and easily meets this
standard in all our major cities, some
smaller municipalities are challenged
with resource capacities.
Generating power, cleaning water using untapped source
The USF-developed NEWgenerator
is to be installed in Durban. It
generates nutrients, energy, and
water by safely recovering them
from wastewater.
Rapid, unplanned urbanisation is
becoming a serious threat across
the world, putting major stress on
critical infrastructure such as water
and sewer lines. Building on his
team’s success in India, Dr Daniel
Yeh, PhD, associate professor of
Civil and Environmental Engineering
at the University of South Florida
College of Engineering, is the
principal investigator of a two-year,
USD1.14-million grant from the Bill &
Melinda Gates Foundation, to install
a new and improved version of his
NEWgenerator in Durban.
The system generates nutrients,
e n e r g y, a n d w a t e r b y s a f e l y
recovering them from wastewater
containing faecal organic matter
and urine. It will accompany a
community ablution block (CAB),
which is a modified shipping
container that has toilets, showers,
and sinks. The South African
government has provided the CABs
to informal settlements that lack
such amenities. However, with
populations growing rapidly in the
30
urban fringe, CABs are putting a
major strain on sewer systems. The
NEWgenerator will aim to allow
CABs to operate without being
hooked up to sewer lines.
Generate energy
The NEWgenerator mimics a
miniature wastewater treatment
plant without the usual energy-
intensive aeration tank that blows
air to break down pollutants and
the plethora of chemicals. By
harnessing an army of anaerobic
microorganisms, the process
eliminates the need for oxygen,
causing organic material to turn into
biogas, a renewable form of energy.
This allows the unit to generate
electricity and run completely on
its own when coupled with solar
panels.
Generate water
The NEWgenerator has a multi-
stage disinfection process. First, a
fine-pore microscopic membrane
filter traps bacteria and viruses.
Then, the clean water that passes
through is disinfected with chlorine,
similar to municipal drinking water.
The recycled water can be used for
toilet flushing in the CABs, thereby
Water Sewage & Effluent January/February 2018
drastically cutting down on water
demand, especially during times of
drought. The water can also be used
for irrigation.
Generate nutrients
Community gardens are often found
throughout unplanned settlements
n e a r C A B s . H o w e v e r, p l a n t
growth is hard to sustain without
fertilizer. Nutrients (nitrogen and
phosphorus) safely recovered with
the NEWgenerator will help make
these community gardens verdant
by providing the fertilizers needed.
This not only creates an urban
greenspace, but a potential food
source and a financial asset as well.
Dr Yeh and USF postdoctoral
researcher Dr Robert Bair leave
for South Africa at the beginning
of 2018 to begin field testing with
their partners at the University of
KwaZulu-Natal. They are one of
four crews selected by the Bill
& Melinda Gates Foundation
to develop technologies called
Reinvented Toilets, which help solve
water and sanitation problems in
Durban and worldwide.
The USF team will bring two
versions of the NEWgenerator
to Durban. The first is an updated