WASTE MANAGEMENT
RECOVERING WASTE
HRS
FINDING VALUE IN LIQUID WASTE STREAMS
Waste is increasingly being viewed as a
resource. From well-established practices
such as recycling paper and aluminium, to
the development of the circular economy,
an increasing volume of resources are now
being recovered from materials that were
previously seen only as inconvenient wastes.
Matt Hale, International Sales and Marketing
Director at HRS Heat Exchangers, looks at
how value can be extracted from liquid
waste streams and what to consider when
choosing technology to achieve this.
WHY RECOVER WASTE?
Waste valorisation is the process of
recovering value from waste materials, for
example through reusing or recycling them,
or by composting or anaerobically digesting
them and converting them into more useful
products such as materials, chemicals, fuels
or other sources of energy. In a circular
economy, compared to a linear one, the
materials within products are reused, turning
previously burdensome wastes into valuable
resources.
The European Union has proposed to double
its rate of resource productivity by 2030 and
as part of this, adopted a communication,
Towards a circular economy: a zero waste
programme for Europe, in July 20141. Like
key industrial stakeholders and businesses,
it asserts that moving to a circular economy
can have a positive effect on economic
growth and strengthen the competitiveness
of companies, in addition to providing a
number of environmental benefits.
UNLEASHING THE
POTENTIAL FOR LIQUID
WASTE STREAMS
Wastewater treatment and ‘water mining’
has also been identified as a key platform
on which to base the technological
development of such circular production
systems2. Effective water treatment and
material recovery can provide a double
economic return. Every cubic metre of
recycled or reused water results in a
corresponding reduction in mains water
demand and wastewater discharge. There
are also benefits in terms of the energy and
carbon footprints associated with material
recovery when compared with primary
extraction and processing, together with
further environmental benefits arising from
reduced waste disposal impacts.
In addition, researchers are increasingly
identifying food processing and supply
chain waste streams as a major resource
for the development of bio-based products
and processes, suggesting that the
valorisation of food waste should focus
on both commodity and higher-value
speciality products.
EXAMPLES OF RESOURCE
RECOVERY
While we are still a significant way away
from the commercial development of
large scale biorefineries which can treat
wastewater streams to produce a range
of products including biofuels, energy,
fertilisers, metals, inert media and a whole
range of fine chemicals, parts of this
process are already established. The use of
anaerobic digestion (AD) to recover energy
and create organic biofertiliser (digestate)
from food and sewage waste is now
widespread, and there are various examples
of material recovery from different waste
streams at all scales, from early research
through to fully commercial recovery units
at industrial facilities and water treatment
works around the world.
Some examples of this type of material
recovery include:
• Recovery of key nutrients such as
phosphorous from sewage streams for use
as agricultural fertilisers.
• The potential recovery of biopolymers
such as polyhydoxyalkanoates (PHAs) and
polyphenols from the wastewater from
olive mills.3
• Cheese whey wastewater (CWW)
comprises waste streams including whey
and wash-out water, and could be treated
using various processes to produce a
range of products which are useful in food
manufacturing and pharmaceuticals, such
as whey proteins, peptides, lactose, glucose
and other useful chemicals.
• The recovery of spent yeast products
from various processes for use in food
production, such as stabilising and pH
buffering.
www.hrs-heatexchangers.com
Issue 36 PECM
145