Water/Wastewater
Treatment and
Sustainability
Dr. Zuzana Bohrerova
Ohio Water Resources Center
Civil, Environmental and Geodetic
Engineering
ASCE sustainable water resources
systems
“water resources systems designed and managed to
fully contribute to the objectives of society, now and
in the future, while maintaining their ecological,
environmental and hydrological integrity”
Are we using water in sustainable manner?
Water Scarcity
water withdrawal as percentage of total available
more than 40%
40%-20%
•
•
•
20%-10%
less than 10%
41% of the world’s population lives in river basins suffering from
moderate to high water stress
Biofuel use and increasing population growth will increase the
percent of the world population living in water stressed areas
Some hypothesize that major wars will be fought over water rights
(water does not respect political borders!)
Access to Clean Water
• Over 1 billion people lack access to safe drinking
water - unhealthy to drink (world population: 6.8
billion)
Access to Sanitation
• 2.5 billion people do Regional medians for sub-Saharan Africa
Simple pit latrine
not have “improved
(Improved)
Open pit latrine
sanitation” (separation
(Unimproved)
of human from their
Pour-Flush latrine
(Improved)
wastes)
Connection to septic system
(Improved)
• Approximately 300
Other (Unimproved)
million of urban
Ventilated improved pit
latrine (Improved)
residents have no
None (Unimproved)
access to sanitation
Shared or public latrine
(Unimproved)
Bucket latrine
(Unimproved)
Connection to public sewer
(Improved)
Some more sustainable WWT
technologies- developing world
• Lagoons/wetlands
– Climate
– Land
– Reuse potential?
• Anaerobic digesters (USAB)
– Small and large scale
– Biogas production and stable humus
– Operation
• SAT (Soil Aquifer Treatment) technologies
– Partially treated effluent used for recharge (Gaza)
– Breaks pipe-to-pipe connection
– Could lower WQ of groundwater
Significance of Water Resources –
U.S. perspective
Drinking water in US is among the best in the
world, BUT
• Emerging contaminants threaten our water
supplies
– Microcystin, Perchlorate, Arsenic, PHACs
• Development in arid, coastal regions
• Many waters are not “fishable and
swimmable”
• Water/wastewater infrastructure security
Water is sustainable renewable
resource, right?
http://www.nap.edu/openbook.php?record_id=12672&page=
52 (Toward a Sustainable and Secure Water Future: A
Leadership Role for the U.S. Geological Survey (2009)
Water Science and Technology Board)
Water Use
Water Withdrawals by Sector
Agricultural
World
Asia
(Not
Middle
East)
Central
America &
Caribbean
Europe
Industrial
Middle
East &
North
Africa
North
America
Domestic
Oceania
• Agriculture dominates water use
South
America
SubSaharan
Africa
Sustainable Water Resources
Management Goals
•
Kennedy and Tsuchihashi, 2006, Is Water Reuse Sustainable?
Water sustainability in agriculture
Water sustainability in agriculture
• Choose the right crops for specific areas
• Improve water harvesting and storage and soil
water retention (organic soils)
• Manage irrigation for efficiency
– Drip irrigation
– Time of irrigation – forecasting and scheduling
• Using reclaimed water for
irrigation
http://www.scientificamerican.com/article/al
l-the-food-using-half-the-water-video/
Water Reuse for Irrigation
• Most reclaimed water contain TDS – salts
• Irrigation needs to be evaluated for long term
sustainability of soil resources
• Salt accumulation in soils – change in root
osmosis and ability to grow (uptake nutrients and
water)
• Israel about 70% reuse water used for irrigation –
salinity problem.
– Strict source control (what is discharged into wastewater)
– Changes in water softening agents and detergents
• Emerging contaminants
Current Urban Water Cycle
5% Q
Waste sludge,
brine (to disposal)
Groundwater or
surface water inputs
(Q)
WTP
Loss to leakage
(33%Q)
City Distribution
System
Outfall
57-66% Q
Waste sludge,
brine (to disposal)
5% Q
WWTP
• Linear treatment system based on disposal
Electricity Use for
Water/Wastewater Treatment in US
• Uses 4% of nation’s electricity
• Majority for moving water/wastewater (80%), rest
treating
• Groundwater supply as water source requires 30%
more electricity (versus surface water)
• Increases in energy consumption:
– Age of delivery systems (friction increase, efficiency
decrease)
– Conservation (systems will operate on below minimum
level; trend to smaller system; economies of scale)
– Improve treatment requirements
– Advanced wastewater treatment 3x more electricity than
trickling system
Drinking water treatment
• EPRI
Wastewater treatment
Current Urban Water Cycle
• Current urban wastewater management is linear
treatment system based on disposal
– Abuse of water for diluting human excreta
– High cost for running and operating current systems
– Collection infrastructure and fast development
• Need of sustainable, closed-loop urban
wastewater management system based on
conservation of water and nutrients
Current water/wastewater treatment
Water
scarcity
High
energy
needs
Aging
infrastructure
NEW
OPPORTUNITY
New technology development
Water recirculation locally
Next generation approaches testing
Approach to Water Infrastructure
Traditional
New Sustainable
Rapid conveyance – underground
concrete pipes and large
treatment plants
Keep significant portion of the
source, use, treatment, and/or
disposal at the local level (site)
Goal – protect public health and
receiving water, flood control
Expand to lighter ecosystem
footprint and enhanced community
benefits
Industrial model of specialization
Integrate water, wastewater and
stormwater – One water
Siloed infrastructure, funding,
regulations and management
Multiple uses and reuses
Driver – economies of scales –
bigger is better
True cost pricing - externalities
Potable water for all uses
Water quality sufficient for
intended use
Nelson, Sustainable Water Infrastructure
Water Reuse
• Not the only solution
• Needs to be combined with:
–
–
–
–
–
water conservation
alternative water supply
green infrastructure
development in treatment technologies
environmental restoration
Water Quality Change
• Electricity consumption decreases sustainability of
water reuse (LCA)
Reclaimed water use
Domestic Water Reuse – dual
reticulation
Water corporation, Australia, published online
Consideration for dual-reticulation
Water corporation, Australia, published online
Water reuse and treatment process
Reverse Osmosis
Advantages
Disadvantages
Modular assembly system
Water needs extensive pretreatment
Installation cost low
Interruption during stormy weather
(too many organics in feed water)
High space/production capacity
ratio
Need for extensive spare parts
inventory
Low maintenance
Brine disposal
Removes TDS
Energy costs
Negligible environmental impact
Needs reliable energy source
Minimal use of chemicals
Membrane fouling
Future development: better membranes,
lower energy requirements
San Diego
San Diego toilet to tap
• Facility available and treating wastewater
• Regulations not in place
• Public oppose direct potable use, but willing to use
as indirect potable use
http://www.sandiego.gov/water/purewater/demo/index.shtml
• Toilet to tap
feasible –
biggest hurdle
is public
perception
Scientific American, CREDIT: Sam Kaplan; STYLING BY LINDA KEIL Halley Resources
Blue Print Columbus
• Sanitary sewer overflows has to be eliminated
• Solution
– Green infrastructure
– OARS deep sewer tunnel
http://www.youtube.com/watch?v=do6jFv_HdbE&feature=youtu.be
References
• Kennedy, L. and Tsuchihashi, R. (2005), “Is Water
Reuse Sustainable? Factors Affecting its
Sustainability. The Arabian Journal for Science
and Engineering, 30(2C), 3-15
• Jhansi, S.C. and Mishra, S.K. (2013), “Wastewater
Treatment and Reuse: Sustainable Options”,
Consilience: The Journal of Sustainable
Development, 10(1), 1-15