resource recovery from wastewater - opportunities and achievements
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Resource Recovery From Wastewater - Opportunities and AchievementsTRANSCRIPT
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Resource Recovery from Wastewater Opportunities and
Achievements
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Water (x 100)
Organics Nutrients
Salts
What can we get from Wastewater?
Water Reuse
Bio-Energy (Organic) Fertiliser
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Vision
Wastewater treatment plants become resource recovery plants
Future hub for key resources
Should be energy neutral or negative
Should be public and private sector orientated
Products should not be directly linked to source
Optimal integration of sources and users
AND: Always ensure public health protection
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Water Use Reduction & Efficiencies
SEQ Water Strategy, QWC
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2010
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2011/2012
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Operating Cost ~ $0.85 / kL
Savings:
$1.5-2.5 / kL fresh water intake
$2 - 3 / kL effluent (trade waste) discharge
Water Recycling in Industry (Brewery)
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Future Water Supply Concepts
Sources
Processes
Uses
Domestic
Wastewater
Industrial
Wastewater
Stormwater/
Run-off
River/ Dam/
Sea Water
Drinking
Water
Non-potable
Domestic
Industrial
Uses
Irrigation/
Farming
Centralised Decentralised Specialised
Physical Chemical Biological Disinfection etc.
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Resource Efficient Recycling Options
Stage 1
Carbon Removal
Nutrient Recovery
Stage 2
Nitrogen
Removal
Stage 3
Water Polishing/
Disinfection
Agricultural irrigation
Low-quality industrial Environmental flows
Industrial reuse
Restricted irrigation
Non-potable domestic
Industrial reuse
Unrestricted irrigation
Potable domestic
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Resource Efficient Recycling Options Stage 1
Carbon Removal
Nutrient Recovery
Stage 2
Nitrogen
Removal
Stage 3
Water Polishing/
Disinfection
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Novel & Existing Processes Options
Anaerobic membrane bioreactor (AnMBR)
Granular high rate anaerobic (UASB/IC, EGSB, Baffled Anaerobic Reactor)
High-rate aerobic (activated sludge) process
Temperature phased anaerobic digestion (TPAD)
Nitritation/anammox combined Moving Bed Biofilm Reactor
Nitritation/anammox combined Sequencing Batch Reactor
Denitrifying anaerobic methane oxidation (DAMO)
Biologically activated carbon (BAC)
Low pressure (membrane) filtration
Sta
ge 1
S
tag
e 2
S
tag
e 3
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Anaerobic MBR Concept
Veolia/Biothane
Key Challenges:
- Low flux large membrane areas - Energy for membrane cleaning
- Fouling potential to be determined
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Energy Self-suffient Process WWTP Strass (Austria, A/B Process)
200,000 EP
Nutrient Removal Plant
Courtesy Bernard Wett
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High Rate Aerobic Processes
Wett & Alex, (2003) WST 48(4)
HRT = 0.25h
SRT = 0.5 d
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High-rate Aerobic Treatment of Industrial WW Laboratory scale SBR optimisation
(Feed COD: 2000 mg/L, HRT: 0.5 day, SRT: 2-4 days)
COD removal > 85%, 20-25% oxidised
Total Nitrogen removal 50-60%
Total Phosphorus removal > 80%
Sludge degradability > 80%
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Temperature-Phased Anaerobic Digestion
Thermophilic
Reactor
T > 55C, 2d HRT
Mesophilic
Reactor
T 35C, 10-14d HRT
Damien Batstone, Paul Jensen, AWMC
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Peak Phosphorus limited resource
Rise in P prices due to increasing
fertilizer demand
Nitrogen/urea price fluctuations
linked to energy/LPG prices
N and P are major challenges for
waste and wastewater management
Pipe blocked due to struvite precipitation
Nutrient Recovery - Motivation
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Works well in concentrated streams eg. digester effluent
but not in dilute solutions
Mg feed often beneficial as concentrated magnesium
hydroxide or MgCl2 solution
Increasing pH improves performance
Precipitation/crystallisation conditions critical for success
N & P Recovery as Struvite
Struvite recovery unit at sewage
treatment plant in Brisbane, QLD
Feed Effluent P-PO4 (ppm)
110 -150 0.5 2 N-NH4 (ppm) 950-1000 800 850 pH 7.5 7.7 8.5 8.7
Chirag Mehta, Damien Batstone, AWMC
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Primary
Treatment
Secondary
Treatment
P
removal
Waste
Water
Secondary
effluent
FeCl3
RO
Treatment
Drinking
water
FePO4
P recovery from Iron Phosphate Sludge
NaCl V
e-
Fe3+, S0
Fe2+, S2-
HS-
S0
ANODE CATHODE
e- PO4
3- in
solution
FeSx
Na2S
NaHS
Stage I: FeS
precipitation
process
Stage II:
Electrochemical
process
Elena Likosova, Stefano Freguia, AWMC
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N, K Recovery using Electrodialysis
An
od
e (+
)
Cat
ho
de
(-)
Concentrate
Wastewater
NH+
K+
NH+
K+
NH+
NH+
K+
NH+
K+K+
Anion ExchangeMembrane (AEM)
K+
NH+
Cation ExchangeMembrane (CEM) AEM AEMCEM CEM
Chirag Mehta, Damien Batstone, AWMC
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Resource Efficient Recycling Options Stage 1
Carbon Removal
Nutrient Recovery
Stage 2
Nitrogen
Removal
Stage 3
Water Polishing/
Disinfection
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What is Anammox?
NH4+
NO3-
0.5 N2
2 O2 (100%)
C-Source (e.g. methanol:
2.2 kg/kgN; COD: >5kg/kgN)
Nitrification
Denitrification
NH4+
0.55 NO2-
0.44 N2 + 0.12 NO3-
0.84 O2 (42%)
Partial Nitritation
Anaerobic ammonia oxidation
0.45 NH4+
Conventional Nitritation/Anammox
A. Joss, EAWAG
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Anammox-type process scale-up
Wett & Dengg (2006)
Approximately 18-24 month process for first full-scale installation
Much shorter (0-6 months) for subsequent installations
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Full-scale plants in operation
Austria Strass, plus others
Switzerland Zrich, Thun, Glarnerland, Limmattal, Niederglatt, St. Gallen. In
planning: Bazenheid, Bern, Geneva
Germany Several plants
The Netherlands Rotterdam, Lichtenvoorde, Olburgen, Mie (others?)
Rest of the world
Biggest plant: Industrial in China, 11,000 kgN/d
A. Joss, EAWAG
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25
ANAMMOX granules
The key for continuous & successful operation:
Simple and compact one step process
Stable and robust operation
Tolerant to peak nitrite levels
Tolerant to peak Suspended Solids levels
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SRT Control - Cyclone for selecting for DEMON Granules
MLSS Overflow Underflow
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Nitritation/anammox Combined in Moving Bed Biofilm Reactor (MBBR)
ANITATM-Mox
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Dewatering Liquor Treatment in Zurich
Two SBR tanks; 2800m3 total volume; 1800m3/d flow; 1200 kgN/d load
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Denitrifying anaerobic methane oxidation (DAMO)
Still under development at lab-scale, very slow bacterial growth but could have
good potential in conjunction with anaerobic and anammox processes
Shihu Hu, Zhiguo Yuan, AWMC
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Resource Recovery Options
Stage 1
Carbon Removal
Nutrient Recovery
Stage 2
Nitrogen
Removal
Stage 3
Water Polishing/
Disinfection
Agricultural irrigation
Low-quality industrial Environmental flows
Industrial reuse
Restricted irrigation
Non-potable domestic
Industrial reuse
Unrestricted irrigation
Potable domestic
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Concluding Thoughts
Water recycling justified by economics and supply security
but needs to improve environmental footprint
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Energy recovery valuable for WWTP operation, plus
economic in industrial situations and/or for (bio-)products
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Nutrient recovery needed for supply security (P) and
increasingly economics (N & K)