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Newsletter and Technical Publications
<Proceedings of the International Symposium on Efficient Water Use in Urban
Areas
- Innovative Ways of Finding Water for Cities ->
C. Session 3: Water Reuse for Non-Potable Applications
Moderator: Mr. Saul Arlosoroff, Water Resources Management-Consultant, Israel
Rapporteur: Mr. Brig Akhtar Zamin, Environmental Protection Agency, Pakistan
Presenters
(1) Prof. Takashi Asano, University of California at Davis, USA
(2) Dr. Bruce E. Jank, Canadian Global Environmental Technologies, Canada
(3) Dr. Gregory Bevan Goldstein, Co-ordinator, Healthy Cities Programme, WHO
Three presentations were made dealing with advantages and problems associated
with the reuse of wastewater for non-potable use.
Key Points Presented:
- Population and urban growth cause enormous increases in the discharge of
human wastes, which are often untreated and discharged, polluting streams,
lakes, groundwater resources and other receiving bodies.
- Flows of untreated human wastes lead to contamination of water resources
and edible agricultural crops, causing health hazards and serious economic
implications.
- Governments should give priority to the treatment of human wastes, with
the objective of enhancing potential reuse for irrigation of non-edible
crops, as well as industrial water uses (for example, for cooling and
process water needs).
- Reuse of treated human wastes represents a significant water resource,
containing important nutrients for intensive agricultural practices.
- Treated sewage effluents can be traded for freshwater resources with local
farmers, thereby making precious water resources available to accommodate
requirements for expanded urban water supply and distribution, to help meet
the needs of the unserved population.
- Reliable measures are required to stop the reuse of raw sewage for
edible crops while at the same time promoting and creating incentives to
connect the flows of treated effluents to agricultural areas.
- Special attention should be given to the potential for chemical
contamination of human wastes from industrial facilities such as metals or
plastics plants, as the treatment and removal of these contaminants is
costly, and the health hazards can be very serious.
- For cities (or sections of cities) without sewers, planning and design
should consider potential future reuse of treated sewage effluents,
and should take steps to direct wastewater flows towards potential reuse
areas.
- Government funds to bridge the gap between discharge points and potential
users (such as farmers and/or industries) should be made available.
- On-site decentralised treatment and reuse should be analysed in terms of
cost-effectiveness, health risks, ecological aspects and overall benefits
(mainly derived from the avoidance or deferral of sewage costs).
Session Recommendations:
- Governments should give priority to the treatment of human wastes,
with the objective of enhancing potential reuse for irrigation of
non-edible crops, as well as industrial water uses (for example, for
cooling and process water needs).
- Reliable measures are required to stop the reuse of raw sewage for
edible crops while at the same time promoting and creating incentives
to connect the flows of treated effluents to agricultural areas.
- For cities (or sections of cities) without sewers, planning and
design should consider potential future reuse of treated sewage
effluents, and should take steps to direct wastewater flows towards
potential reuse areas.
- Government funds should be allocated to bridge the gap between
discharge points and potential users (such as farmers and/or
industries).
- On-site decentralised treatment and reuse should be analysed in
terms of cost-effectiveness, health risks, ecological implications and
overall benefits (mainly derived from infrastructure avoidance or
deferral).
- Reuse of treated human wastes is a major source of water otherwise
wasted and a potential polluting source. Governments (federal,
national or local) should create the enabling environment to promote
reuse by providing adequate budgets, incentives and disincentives,
especially in water-scarce cities and regions.
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