water/wastewater treatment and sustainability dr. zuzana bohrerova ohio water resources center...

Water/Wastewater Treatment and

SustainabilityDr. Zuzana Bohrerova

Ohio Water Resources Center

Civil, Environmental and Geodetic Engineering

Water Sustainability

What is sustainability?

Conference on Sustainable Development 2012 (Rio+20): Water is “at the core of sustainable development as it is closely linked to a number of key global challenges”

Water Sustainability

SOURCE: UN water.org, 2013

Triple bottom line approach to sustainability:ENVIRONMENTAL

ECONOMICSOCIETAL

Water Sustainability

• Are we using water in sustainable manner?

Water Use

Water Use

Water Footprint

SOURCE: UN water.org, 2013

• http://www.waterfootprint.org/?page=files/productgallery

Water Scarcity

• 41% of the world’s population lives in river basins suffering from moderate to high water stress

Water Quality

SOURCE: UN water.org, 2013

Achieving Sustainability Goals (UN)

• TARGETS (draft, after 2015)

– Universal access to safe drinking water, sanitation and hygiene

– Improve by x% the sustainable use an development of water resources in all countries

– All countries strengthen equitable, participatory and accountable water governance

– Reduce untreated wastewater by x%, nutrient pollution by y% and increase wastewater reuse by z%

– Reduce mortality by x% and economic loss by y% from natural and human-induced water-related disasters

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 x Energy Nexus issues

Current Urban Water Cycle

• Linear centralized treatment system based on disposal

WTP

WWTP

Groundwater or surface water inputs

(Q)

Waste sludge, brine (to disposal)

Waste sludge, brine (to disposal)

5% Q

5% Q

Loss to leakage(33%Q)

Outfall57-66% Q

City DistributionSystem

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

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 Energy Nexus• Water and energy systems are interdependent

SOURCE: DOE, energy.gov, 2014

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

Decentralized vs centralized systems

Centralized Decentralized

Advanced collection and treatment Treated onsite

Out of sight More public participation

One technology for a regionFlexibility in process used and

management

More expensive for capital cost and operation and management

Expenses transfer to individuals

Control and regulation easy Hard to control and regulate

Lower spatial requirements per capita Space requirements

Operator expert Everyone expert

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

Evaluation Sustainability of WWTP

Muga and Mihelcic, 2008, Journal of Env. Management, 88:437-447

Wastewater operators

Land Requirements

Utility Services Leading Sustainability

From US EPA:• Alternative fuels• Automation• Resource recovery• Resiliency• Customer engagement – conservation• Investment in capital facility maintenance

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

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

Domestic Water Reuse – dual reticulation

Water corporation, Australia, published online

Water reuse and treatment process

Reverse OsmosisAdvantages Disadvantages

Modular assembly system Water needs extensive pre-treatment

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 publicperception

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