Purpose
This Policy Position Statement provides an overview of the
significance and promotability of large scale water reuse schemes
delivering more than 10Ml/d of water resource, for people and the
environment. For the UK, like many other areas of the world with a
need to bridge the gap between water supply and demand in the long
term, large scale water reuse (or effluent reuse) is a relatively
untapped way of providing water to meet the long term needs of
people and the environment, in the face of future uncertainties
such as climate change.
CIWEM calls for:
- The promotion of large scale water reuse schemes to reclaim
water resources, and to facilitate a dependable and a secure long
term water supply, in the face of future uncertainties such as
climate change.
- A coherent government policy and the publication of guidelines
on water reuse, coupled with well-founded water reuse quality
standards for the protection of public health and the environment.
Reducing carbon footprints and improving energy efficiency of
existing schemes should underpin any water reuse policy.
- Treatment of waste water to an appropriate standard for the
permitted end use, recognising that there is a need to protect
public health and the environment, and to deal with potential
public concerns associated with water reuse.
- Local planning authorities in water stressed regions to bring
forward proposals in their Development Plan Documents for local
requirements on sustainable buildings which reflect the need for
new development to be water efficient, in accordance with the
Government's recent Planning Policy Statement: Planning and Climate
Change.
- The building industry to further explore and promote innovative
small scale domestic water reuse opportunities
- Research and development into low carbon, large scale,
sustainable and economic water reuse treatment methods, and the
monitoring, with a view to sharing and learning from best practice,
of water reuse practices in countries such as the USA, Australia,
Japan, Israel, Jordan, South Africa and Spain where water reuse is
taking place for a number of agricultural, industrial and leisure
irrigation uses.
The Chartered Institution of Water and Environmental Management
(CIWEM) is the leading professional body for the people who plan,
protect and care for the environment and its resources, providing
educational opportunities, independent information to the public
and advice to government. Members in 96 countries include
scientists, engineers, ecologists and students.
Context
The concept of water reuse to augment water resources is not
new. Water reuse can be split into planned and unplanned, direct
and indirect, large scale and small scale. Large scale water reuse
to replenish river water resources has occurred ever since the
introduction of community waste water treatment works. Much lowland
abstraction will comprise a proportion of treated waste water
discharges derived from upstream wastewater treatment works.
Considerable untapped potential exists for the promotion of
water reuse schemes. The greatest potential for reuse will be in
areas where discharges are currently made to the sea, or to inland
waters that are not abstracted from further downstream, as they
could be redirected inland to support river flows and abstractions.
Mobilisation of the untapped potential requires actions and
policies from the government, regulators, water undertakers and the
public.
The categorisation of water reuse schemes is often confused.
Large scale water reuse schemes delivering more than 10Ml/d of
water resource may be split into planned and unplanned and direct
and indirect (Akande and Spraggs, 1999).
Planned reuse is where waste water discharges, with additional
specialised treatment, are purposely used to enhance water
resources. Unplanned reuse is where waste water discharges enhance
water resources, but no account is taken of their impact and no
specialist treatment is involved (other than those required to
satisfy normal waste water discharge permissions). Unplanned reuse
can evolve into planned reuse if large amounts of waste water are
discharged into large catchments; for example in the Thames Basin,
where on average, one third of London's drinking water is estimated
to be recycled waste water (Young, 1984). Planned and unplanned
reuse may be either direct or indirect, although unplanned reuse is
almost always indirect. Direct reuse is where treated waste water
is transferred from a waste water treatment works to the reuse site
without intervening discharge into a natural body of water or a
reservoir. Such reuse is sometimes called pipe to pipe reuse, and
is relatively uncommon for public water supply purposes, but more
so for industrial applications. Indirect reuse is where treated
waste water is discharged or transferred from a waste water
treatment works to a river, a canal or reservoir prior to
subsequent abstraction, and treatment to appropriate water
standards (if required), and reuse.
Waste water can comprise: discharges from community sewage works
or sewers, waste water from industrial processes, waste water from
household properties and run-off from highways in wet weather.
Water reuse opportunities may be associated with: raw water sources
for potable water supplies, raw water sources for non potable water
supplies, industrial process water, replenishment of water
resources for ecological impact mitigation, irrigation water and
wetland regeneration.
A large scale water reuse scheme is a relatively untapped way of
providing water to meet long term needs of people and the
environment, in the face of future uncertainties such as climate
change. The development of a water reuse strategy will depend upon
a number of factors including: pattern of demand, extent and type
of conjunctive use, operational flexibility and cost. A water reuse
scheme may be used to meet either base or peak demand, and can be
operated either in isolation or in conjunction with other water
sources.
Key Issues
Promotion of large scale water reuse schemes can be justified on
account of a significant gap in long term water supply and demand
projections. For such schemes to be cost effective they must
integrate with existing and probable future water supply
arrangements.
- Supply Demand Balance and Climate Change: Water reuse schemes
specifically engineered to enhance water resources could help
bridge the gap between long term supply and demand balance
projections, especially in the growth regions of the South and East
of England where other more sustainable options may be more
limited.
- Existing Arrangements: Water reuse to replenish river
water resources has occurred ever since the introduction of
community waste water treatment works. As an indirect consequence
of this, much lowland abstraction from rivers will comprise a
proportion of treated waste water discharged from upstream
treatment works.
On a catchment scale, the large scale Langford scheme (Chelmer
Recycling Scheme, Essex) is an example of a successful indirect
water reuse scheme, where treated waste water is mixed with the
water from the River Chelmer, which is abstracted at Langford, near
Maldon, for Hanningfield reservoir refill. The Langford scheme, at
40Ml/d is associated with a population of up to 100,000 and is a
biofor system for phosphate and nitrate removal, with powdered
activated carbon for oestrogen removal and UV for disinfection,
Some of the water is stored only in 7 day bankside storage lagoons
before having normal water treatment. It does not have reverse
osmosis treatment. The scheme has been operating for around 5
years.
On a local scale, and more recently, direct and small scale water
reuse facilities through industrial processing, for further
industrial use has been practised and these include car wash water
recycling for subsequent car wash and vegetable wash waste water
for subsequent irrigation use. In some cases waste water discharges
from community waste water treatment works has been used. There are
now examples of waste water from household use, such as sink and
bathrooms (grey water), being re-used as cistern flush water.
However these units are still expensive at the single household
scale.
Direct and indirect water reuse practice is also a feature of
irrigation systems in resource stressed and semi-arid areas of
Australia, the USA and Spain. In some areas treated waste water
from sewage works is used to replenish groundwater resources.
- Possible Future Arrangements: The greatest potential for large
water reuse scheme will be in areas where waste water discharges
are currently made to the sea, as they could be redirected inland
to support river flows and abstractions. But, the treatment of
waste water in these areas to an appropriate standard for end use,
when there is a need to protect public health and the environment
must be guided by a coherent government policy and guidelines on
water reuse, coupled with authoritative water reuse quality
standards.
For discharges to the ground, the risk to groundwater resources
should considered, taking into account the source and pathway
associated with each discharge, to assess the potential risk to
groundwater. In this respect, the size and quality of the
discharge, the discharge arrangement and the nature of any
industries in the catchment should be established. The purification
characteristics of the soil and sub soil and the hydro(geo)logical
conditions at each discharge location should be assessed.
The market for small scale household water reuse is growing slowly
but many new build developments have potential for purpose-built
water reuse facilities. Retrofit installation of greywater systems
on existing individual properties has a long payback period and is
not attractive using current technology.
Discussion
Considerable untapped potential exists for the promotion of
water reuse schemes. The greatest potential for reuse will be in
areas where discharges are currently made to the sea, or to inland
waters that are not abstracted from further downstream, as they
could be redirected inland to support river flows and abstractions.
Mobilisation of the untapped potential requires policies from
government and regulators, and positive action from water
undertakers, to address public concerns on health and safety in
re-using water.
CIWEM calls for the promotion of large scale water reuse schemes
to reclaim water resources, and to facilitate a dependable and a
secure long term water supply, in the face of future uncertainties
such as climate change. Climate change scenarios suggest that the
UK is likely to experience drier, warmer summers (Hulme et al,
2002) with more frequent periods of extended drought. Demand for
water is also expected to rise (Downing et al, 2003).
Uncertainties such as climate change may result in significant
supply demand balance deficits in the long term, if at different
times in different places.
In the UK, there are a number of policy drivers for water reuse
including the Urban Waste Water Treatment Directive, the Water
Framework Directive, the Integrated Pollution Prevention and
Control Directive as well as more local Catchment Abstraction
Management Strategies. Further details are given in Appendix 1. The
House of Lords Science and Technology committee, in their recent
Water Management report, stated that "there is scope for greater
industrial use of waste water that has been treated to a
sub-potable standard" and that the government needs to investigate
how this can be encouraged (House of Lords Report on Water
Management, 2006 p69). Defra's recent Water Strategy, Future
Water, is positive towards wider industrial water reuse and the
development of standards for non-potable water re-use, but does not
discuss the potential for wider large-scale re-use schemes.
CIWEM calls for the promotion of a coherent government policy on
water reuse, coupled with the development and publication of
well-founded water reuse quality standards. The standards must be
robust and protect public health and the environment. Reducing
carbon footprints and improving energy efficiency of existing
schemes should underpin any water reuse policy. The government
guidelines must incorporate best practice and a risk management and
multiple-barrier approach to managing potential health and
environmental risks from water reuse. Australia and the USA both
have national guidelines for water reuse, and government support
for large scale water reuse schemes. Good educational programmes
for raising public awareness of water reuse have been developed in
Singapore and the USA. Lessons should be learnt and applied
elsewhere.
Water reuse can involve high energy use in advanced waste water
treatment and pumping. The impact of water reuse schemes on
greenhouse gas emissions will therefore need to be compared with
other water supply options, including desalination, rainwater
harvesting, winter storage reservoirs, and demand side options to
reduce forecast deficits in the supply-demand balance.
International experience at both the strategic and project level
can help inform decisions about water quality standards, and the
energy efficiency of potential water reuse schemes.
CIWEM considers that the factors that should be taken into
account when identifying reuse opportunities with the greatest
resource advantage include: development of an inventory of sources
and sinks of waste water discharges in water bodies, quantification
of the relative magnitudes of the sources and sinks and the
feasibility of reuse if sinks are bigger than sources. Water bodies
in this case cover river catchments, aquifer units and coastal
regions.
CIWEM calls for treatment of waste water to an appropriate
standard for end use when there is a need to protect public health
and the environment, to deal with potential public concerns
associated with large scale water reuse. Although water reuse has
been practised indirectly for decades through the existing water
cycle of abstractions and discharges to rivers, the reuse of water
does carry potential risks that need to be addressed. For instance,
pathogens and biological agents that can potentially cause disease
and illness may be present in any waste water that is discharged to
a water course and is subsequantly reused for water supply. There
are also potential impacts on fish and the riverine environment and
the probable impact of the build up of contaminants over time in a
closed system.
The UK water industry considers that existing standards of water
reuse consenting (to meet environmental quality standards and
Directives) and conventional drinking water treatment is sufficient
to protect public health. Recent anthropological studies have shown
that the general public do not like experiencing other peoples
waste and would possibly be concerned if they were aware of current
practices of indirect recycling. As the process of consultation is
now widely practised, and will be reinforced through the Water
Framework Directive, then not only will new schemes be exposed but
concerns may be raised over existing arrangements.
In order to address potential public concerns, the issue of
whether or not additional standards are required for the control of
waste water discharges, associated with future development of reuse
opportunities, must be considered. There may also be a need for
additional treatment reliability to reduce the risk of failure, and
to incorporate barriers to possible breakthrough of contaminants.
To this end, the United Kingdom Water Industry Research
(UKWIR)/American water works association Research Foundation
(AwwaRF) and Water Reuse Foundation (WRF) have recently completed a
project titled: "A Protocol for Developing Water Re-Use Criteria
with Reference to Drinking Water Supplies" (UKWIR, 2005). The
project proposed a framework that deals with standards for the
control of waste water discharges to address potential public
concerns. The framework also provides a basis for more widespread
acceptance of the existing practice of using treated and blended
waste water as a raw water source, and as a replacement for other
uses of conventional drinking water sources. The project identified
a number of knowledge gaps that can potentially restrict the
introduction and application of waste water reclamation and reuse
strategies.
CIWEM calls for the building industry to promote and further
explore innovative small scale domestic water reuse opportunities.
The South and East of England are considered to be the economic
powerhouse of the country, but there is a housing shortage. The UK
government has plans for development of new housing in four key
areas of: the Thames Gateway, Ashford, Milton Keynes and South
Midlands, and the London-Stansted-Cambridge-Peterborough corridor.
This should provide ample opportunities for further exploration of
innovative water reuse schemes in the long term.
CIWEM urges local planning authorities in water stressed regions
to bring forward proposals in their Development Plan Documents for
local requirements on sustainable buildings which reflect the need
for new development to be water efficient, in accordance with the
Government's recent Planning Policy Statement: Planning and Climate
Change. Specifying the higher levels of the Code for Sustainable
Homes in such areas will encourage deployment of technologies such
as rainwater harvesting or grey water recycling systems in support
of housing developments.
CIWEM calls for research and development in low carbon, large
scale, sustainable and economic water reuse treatment methods and
the monitoring, with a view to sharing and learning from best
practice, of water reuse practices in countries such as the USA,
Australia, Japan, Israel, Jordan and South Africa and Spain where
water reuse is taking place for a number of agricultural and
industrial uses. In the UK, more research and development into the
feasibility and environmental economics of large scale water reuse
schemes is needed to be able to identify suitable associations
between water and sewerage service providers and industries for the
promotion of beneficial large scale schemes.
Research and development activities should involve water reuse
demonstration plants that can be used to investigate different
treatment technologies. Some work has been carried out to explore
dual distribution infrastructure systems at community level for
small scale water reuse and CIWEM advocates such pilot studies
where the results may be helpful in developing innovative solutions
for new communities.
February 2008
Useful References
Akande, K. and Spraggs, G., 1999. Assessing the Gain in
Deployable Output from Effluent Re-Use Concepts: A Case Study,
Proceedings of the CIWEM National Conference on Making Better use
of Water Resources, pp 83-104.
Defra, 2008. Future Water. Defra. January 2008
Downing, T.E, Butterfield, R.E., Edmonds, B., Knox, J.W., Moss,
S., Piper, B.S. and Weatherhead, E.K. (and the CCDeW project
team)., 2003. Climate Change and the Demand for Water, Research
Report, Stockholm Environment Institute Oxford Office, Oxford.
Environment Agency, 2006. Do we need large-scale water transfers
for south east England?
http://www.environment-agency.gov.uk/commondata/acrobat/grid_1464452.pdf.
Environment Agency. September 2006. Accessed 15/05/07.
Hulme, M., Jenkins, G.J., Lu, X., Turnpenny, J.R., Mitchell,
T.D., Jones, R.G., Lowe, J., Murphy, J.M., Hassell, D., Boorman,
P., McDonald, R. and Hill, S., 2002. Climate change scenarios for
the United Kingdom: the UKCIP02 Scientific report. Tyndall Centre
for Climate Change Research, University of East Anglia, Norwich,
UK.
UKWIR, 2005. A Framework for Developing Water Reuse Criteria
with Reference to Drinking Water Supplies.
Young, D. D., 1984. Re-Use of Water via Rivers for Water Supply
and Re-Use of Sewage Effluent. In Proceedings of International
Symposium on Water Recycling. Institution of Civil Engineers,
London.
Appendix: Some Policy Drivers for Water Reuse in the UK
The main policy drivers that will influence the implementation
of future water reuse schemes in the UK are as follows:
- Urban Waste Water Treatment Directive: This European
legislation aims to protect the environment from the adverse
effects of urban waste water discharges. It requires municipal and
certain industrial waste water deriving from areas with a
population equivalent of more than 15 000 to receive secondary and
tertiary treatment. Waste water from smaller settlements must also
receive some form of treatment and sensitive waters must be
properly protected. The Directive also asserts that sewerage
undertakers must ensure treated waste water is reused 'whenever
appropriate'. Although this assertion is somewhat vague, as a
minimum it suggests that the potential for water reuse must be
considered, to determine whether either is 'appropriate' given the
circumstances
- Water Framework Directive: This European Directive requires
inland, estuarine and coastal waters to reach "good status" by
2015. The water environment must be managed in an integrated manner
on the basis of river basin districts. To achieve good status:
agriculture, water companies and industry will be required to be
more stringent in preventing the discharge of pollutants into
receiving waters. Only sustainable levels of abstraction from
rivers will be allowed because certain minimum flows are required
to support the algae, plants, fish and macro-invertebrates whose
presence confers good ecological status on a water body.
Reduced abstraction and more stringent discharge consents are
likely to lead to more businesses considering water recycling and
reuse
Where treated waste water is discharged to rivers and forms a
significant component of baseline river flow in periods of low
rainfall, water reuse and recycling could result in diminished
river flows and resultant ecological implications. Where waste
water is discharged directly to the sea, this problem is avoided
(Environment Agency, 2006)
- Integrated Pollution Prevention and Control Directive: The IPPC
Directive requires potentially highly-polluting industry to obtain
a permit which is only issued if certain environmental criteria are
met and information is provided about how the company will reduce
and prevent various kinds of pollution (including waste water
discharges)
- Catchment Abstraction Management Strategies (England and Wales
only): The aim of these locally-developed documents is to help
balance the demands of water abstractors and the aquatic
environment and ensure that decisions are made equitably and
publicly. To ensure abstraction is sustainable, those wishing to
abstract significant quantities of water require a licence. This
licence has certain conditions such as a maximum quantity that can
be abstracted and a minimum flow requirement before any abstraction
can take place. Businesses which cannot obtain sufficient licences
to meet their requirements must find an alternative water supply.
Catchment Abstraction Management Strategies have been developed by
the Environment Agency and as such cover only England and
Wales
Whilst there are currently no directly comparable strategies in
Scotland or Northern Ireland, both now have an abstraction
licensing system.
