C. Wisniewski Montpellier University, France
UMR QualiSud
Faculté des Sciences Pharmaceutiques et Biologiques
Wastewater treatment plants : wastewater
resource recovery facilities ?
Wastewater treatment plants : wastewater resource recovery facilities ?
OUTLINES Current state of Wastewater Treatment (WWT) Climate Change's Relation to Wastewater Treatment A new Paradigm for Wastewater Treatment Plant (WWTP)
Wastewater treatment plants : wastewater
resource recovery facilities ?
Wastewater Treatment adaptation according to Climate Change
Wastewater treatment plants : wastewater
resource recovery facilities ?
WASTEWATER
WASTEWATER TREATMENT PLANTS
DISCHARGED IN WATER BODIES
Urban and agricultural runoff
Municipal sewage effluent Industrial effluent
Parameter mg/L
TSS 250 to 600
COD 500 to 1200
BOD 230 to 560
N total 30 to 100
P total 6 to 25
Level of treatment required before discharge imposed by European Directives
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Urban Wastewater Treatment Directive (91/271/EEC1)
Protection of the aquatic environment from the adverse effects (such as eutrophication) of urban (and industrial) wastewater
Phosphorus and Nitrogen
Sensitive areas
Collection and treatment of wastewater in all agglomerations with a population equivalent larger than 2000
Parameter mg/L % reduction
COD 125 75
BOD 25 70 - 90
N total 10 - 15 80
P total 1 - 2
Objective
Implementation and Improvement of many WWTPs the last few years…
SIGNIFICANT IMPACT ON WASTEWATER TREATMENT
Wastewater treatment plants : wastewater
resource recovery facilities ?
Water Framework Directive (2000/60/EC2000)
Protection and restoration of clean water across Europe
Identification of priority substances that have to be reduced in water bodies
Achieve “good status” by 2015 and to prevent deterioration to water bodies
Objective
Implementation of additional treatment steps in many WWTPs …
Micro-pollutant
Emerging contaminants
Primary treatment
Wastewater treatment plants : wastewater
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Secondary treatment
Pre-treatment Tertiary treatment
CONVENTIONNAL WASTEWATER PLANT… TODAY
DISCHARGE
Removal of suspended solids
(settling)
Removal of organic matter and of some nutrients
(aerobic or anaerobic processes)
Improvement of the effluent quality before
its discharge (effluent polishing)
Primary treatment
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resource recovery facilities ?
Secondary treatment
Pre-treatment Tertiary treatment
Sludge treatment DISCHARGE
CONVENTIONNAL WASTEWATER PLANT… TODAY
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resource recovery facilities ?
A SIMPLE WASTE TREATMENT UNIT … REQUIRING ENERGY … PRODUCING SLUDGE
ENERGY SLUDGE
CLIMATE CHANGE
What is the future of WASTEWATER TREATMENT plants?
CONVENTIONNAL WASTEWATER PLANT… TODAY
Wastewater treatment plants : wastewater
resource recovery facilities ?
Climate Change Impact on WWT
WWT Impact on Climate Change
CLIMATE CHANGE
What is the future of WASTEWATER TREATMENT plants?
Wastewater treatment plants : wastewater
resource recovery facilities ?
More intensive rainfall events
Extreme weather events
Higher climate variability
Very few references on the assessment of climate change
impacts on WWT
Increased evaporation rates
Changes in frequency and timing of precipitation events
Earlier snowmelt
Temperature elevation
Climate Change Impact on WWT
Wastewater treatment plants : wastewater
resource recovery facilities ?
Changes in frequency and timing of precipitation events
Temperature elevation
Increase of sewage influent
PEAK FLOW RATES Large majority of existing
sewers in most EU countries
Combined sewers
Modifications of SOLIDS-LIQUID SEPARATION
Modification of BIOLOGICAL REMOVAL RATES
Conventional Process models unable of describing and predicting
the effects of SHOCK-LOADING EVENTS
Water Sci Technol. 2009, 60(2):533-540
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SIGNIFICANT IMPACTS on the overall environmental performance
GREENHOUSE GAS (GHG) EMISSIONS
ENERGY SLUDGE
WWT Impact on Climate Change
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resource recovery facilities ?
Intergovernmental Panel on Climate Change (IPCC), 2007 .
Global Greenhouse Gas Emissions by Source (USA)
GHG emissions from
wastewater represent 0,6 %
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GHG emissions
CO2
CH4
N2O
N2O
CH4 Sludge thickening and disposal
Nitrous oxide (N2O) Carbon dioxide (CO2) Methane (CH4)
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CO2
CH4
N2O
N20
CH4 Sludge thickening and disposal
Nitrous oxide from nitrification/denitrification processes
Carbon dioxide from aerobic process
Methane from anaerobic processes
Managing Water Resources under Climate Uncertainty, Part of the series Springer Water. 2001 : 197-220
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REMOVE ORGANIC MATTER NITROGEN PHOSPHOROUS Micropollutant
GENERATE SOLID WASTE GHG
CONSUME ENERGY
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FACTORY Resources recovering and recycling
Treatment and disposal ENERGY SLUDGE
GHG
A NEW PARADIGM FOR WWTP IS NOW NECESSARY
WHAT CAN WE GET FROM WASTEWATER?
Extracting resources from wastewater is not new … but becomes crucial
WHAT CAN WE GET FROM WASTEWATER?
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resource recovery facilities ?
Water (for reuse)
Energy
Nutrient
Other value-added materials…
http://www.biocycle.net/2014/08/14/power-positive-resource-recovery/
Wastewater treatment plants : wastewater
resource recovery facilities ?
Energy
http://www.biocycle.net/2014/08/14/power-positive-resource-recovery/
There is more energy in wastewater than is required to treat it
There are different types of energy in wastewater
Heat Energy
Biological/chemical Energy
0.05 kW
1 m3/d
0.26 kW assuming that a 12° change in
temperature could be extracted
Energy demands
0.02 kW
15 times higher than the energy required for
treatment
In the ORGANIC MATTER
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resource recovery facilities ?
http://www.biocycle.net/2014/08/14/power-positive-resource-recovery/
Heat Energy
Biological/chemical Energy
0.05 kW
0.26 kW assuming that a 12° change in
temperature could be extracted
Low-grade heat Low energy quality
Any significant amount of power produced
In the ORGANIC MATTER
40% of this energy can be converted into electrical power
0.02 kW
Power Positive Wastewater Treatment power production equivalent to the power demand
Wastewater treatment plants : wastewater
resource recovery facilities ?
Energy
http://www.ajol.info/index.php/wsa/article/view/115257/104844 http://www.biocycle.net/2014/08/14/power-positive-resource-recovery/
Aerobic treatment requires air and demands more power than anaerobic treatment that produces biogas that can be used to fuel power production.
LARGE DEVELOPMENT OF ANAEROBIC PROCESSES FOR ORGANIC MATTER REMOVAL
Research about conversion of digester gas (methane) into methanol
Anaerobic digestion might be coupled with other process to produce methanol, ammonia, or other products from digester gas.
Wastewater treatment plants : wastewater
resource recovery facilities ?
Nutrient Recovery
Abundant in the atmosphere BUT
takes a considerable energy input to capture it and convert
it into a fertilizer product
Volatility of the natural gas market
NITROGEN PHOSPHOROUS
Non-renewable resource for which there is no substitute
Rise in P prices due to
increasing fertilizer demand
MOTIVATIONS
Wastewater contains nutrients such as phosphorus and nitrogen
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resource recovery facilities ?
PHOSPHOROUS
http://inside.bluetechresearch.com/streams/themes/nutrient-recovery-energy-and-resource-recovery/
Approximately 18% of the EU’s total phosphorus goes into sludge and could be recycled
Many countries are starting to promote measures to recover phosphorus from wastewater
Sweden Switzerland
UK and Germany
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PHOSPHOROUS
Water Pollution . 2015, 1 (3) : 155-166
Ion exchange and adsorption
Bio-electrochemical system
Membrane separation
NITROGEN
Chemical precipitation
Biological assimilation
Chemical reduction and extraction
Physical-chemical adsorption and ion exchange
Physical filtration and membrane process
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resource recovery facilities ?
Nitrogen and Phosphorus recovered by precipitation (e.g. struvite)
Both Phosphorus and Ammonium can be simultaneously removed and precipitates can be used as a fertilizer.
Separation of urine and solids
Urine accounts for only 1% of the total volume of wastewater, but it contains up to 80% of all the nutrients.
NITROGEN and PHOSPHOROUS
Urine contains phosphate (PO4) and ammonium (NH4). When magnesium (Mg) is added to urine, phosphate, ammonium and magnesium bind and form struvite (MgNH4PO4•6H2O), which can then be filtered out, collected, and dried into a powder
http://www.sswm.info/content/struvite-0
Wastewater treatment plants : wastewater
resource recovery facilities ?
NITROGEN and PHOSPHOROUS
The process is distinguished by the fact that municipal sewage sludge from wastewater treatment plants with simultaneous phosphate elimination with iron salts could be used without any changes in the process of wastewater treatment. The resulting product can be applied, for example, directly as fertilizer in agriculture.
http://www.iswa.uni-stuttgart.de/lsww/forschung/awt/2012_2013_Forschungsprojekte/Pilotanlage_MAP.en.html
Large-scale Application of Phosphorus (Struvite) Recovery from Digested Municipal Sludge
"Stuttgart Process"
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Other value-added materials…
Environ. Sci. Technol. 2015, 49 (16): 9479–9488
U.S. sewage sludges were analyzed for 58 elements by ICP-MS and
electron microscopy
Identification of 13 lucrative elements
Platinum, silver, iron, zinc, copper, gold
€ 2 million
1 ton of sludge
16,7 g Ag - 0,33 g Au
Wastewater treatment plants : wastewater
resource recovery facilities ?
LIST OF MATERIALS THAT CAN BE POTENTIALLY EXTRACTED FROM WASTEWATER
Nutrient Recovery: State of the Knowledge 2011, Water Environment Research Foundation
PHA (polyhydroxyalcanoate) Production
Biopolymers of commercial interest
PHA storage is a widespread bacterial property
Wastewater treatment plants : wastewater
resource recovery facilities ?
Water Reuse
DEMAND FOR ALTERNATIVE POTABLE
SUPPLY SOURCES
CLIMATE CHANGE
Decrease in the availability of freshwater
Deterioration of freshwater
resources
Wastewater reuse will become more necessary as climate change accelerates
Primary treatment
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resource recovery facilities ?
Secondary treatment
Pre-treatment Tertiary treatment
Sludge thickening and disposal
R
E
U
S
E
Primary treatment
Wastewater treatment plants : wastewater
resource recovery facilities ?
Pre-treatment
Sludge thickening and disposal
Membrane bioreactor (MBR)
R
E
U
S
E
High wastewater discharge quality
High level of wastewater recycling
Primary treatment
Wastewater treatment plants : wastewater
resource recovery facilities ?
Pre-treatment
Sludge thickening and disposal
Membrane bioreactor (MBR)
R
E
U
S
E
Increase of the global market for membrane bioreactors
A new paradigm for WWTPs
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resource recovery facilities ?
FACTORY Resources recovering and recycling
Treatment and disposal
Effective and cost efficient Without side-effects Promoting equity Technically and socially feasible Preventing long term negative effects
MESURES
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resource recovery facilities ?
What limits will be imposed?
How much will it cost and who will finance it?
Changes in polices and regulations
Changes in public attitude (e.g. to use reclaimed water)
… wastewater reuses, and energy and nutrient recovery from wastewater have to be actively encouraged
A new paradigm for WWTPs Nutrient factory
Energy factory
Water factory