Resource Recovery from
Wastewater – Opportunities and
Achievements
What can we get from Wastewater?
Water
(x 100)
Salts
(Organic) Fertiliser
Water Reuse
Bio-Energy
Nutrients Organics
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
Water Use Reduction & Efficiencies
SEQ Water Strategy, QWC
2010
2011/2012
Water Recycling in Industry (Brewery)
Operating Cost ~ $0.85 / kL
Savings:
$1.5-2.5 / kL fresh water intake
$2 - 3 / kL effluent (trade waste) discharge
Future Water Supply Concepts
Sources
Processes
Uses
River/ Dam/
Sea Water
Domestic
Wastewater
Industrial
Wastewater
Stormwater/
Run-off
Centralised Decentralised Specialised
Physical Chemical Biological Disinfection etc.
Drinking
Water
Non-potable
Domestic
Industrial
Uses
Irrigation/
Farming
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
Resource Efficient Recycling Options
Stage 1
Carbon Removal
Nutrient Recovery
Stage 2
Nitrogen
Removal
Stage 3
Water Polishing/
Disinfection
Novel & Existing Processes Options
Stage 1
• Anaerobic membrane bioreactor (AnMBR)
• Granular high rate anaerobic (UASB/IC, EGSB, Baffled
Anaerobic Reactor)
• High-rate aerobic (activated sludge) process
Stage 2
• Temperature phased anaerobic digestion (TPAD)
• Nitritation/anammox combined Moving Bed Biofilm Reactor
• Nitritation/anammox combined Sequencing Batch Reactor
Stage 3
• Denitrifying anaerobic methane oxidation (DAMO)
• Biologically activated carbon (BAC)
• Low pressure (membrane) filtration
Anaerobic MBR Concept
Key Challenges:
- Low flux – large membrane areas
- Energy for membrane cleaning
- Fouling potential to be determined
Veolia/Biothane
Energy Self-suffient Process
WWTP Strass (Austria, A/B Process)
200,000 EP
Nutrient Removal Plant
Courtesy Bernard Wett
High Rate Aerobic Processes
HRT = 0.25h
SRT = 0.5 d
Wett & Alex, (2003) WST 48(4)
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%
Temperature-Phased Anaerobic Digestion
Mesophilic
Reactor
T ≈ 35°C,
10-14d HRT
Thermophilic
Reactor
T > 55°C,
2d HRT
Damien Batstone, Paul Jensen, AWMC
Nutrient Recovery - Motivation
• 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
N & P Recovery as Struvite
• 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
Feed
P-PO4 (ppm) 110 -150
N-NH4 (ppm) 950-1000
pH
7.5 – 7.7
Effluent
0.5 – 2
800 – 850
8.5 – 8.7
Struvite recovery unit at sewage
treatment plant in Brisbane, QLD
Chirag Mehta, Damien Batstone, AWMC
P recovery from Iron Phosphate Sludge
FeCl3
Waste
Water
Primary
Treatment
Secondary
Treatment
V
eFe3+, S0
Fe2+, S2-
Secondary
effluent
NaCl
e-
P
removal
RO
Treatment
Drinking
water
Na2S
FePO4
PO43- in
solution
HS-
FeSx
S0
NaHS
ANODE
CATHODE
Stage II:
Electrochemical
process
Stage I: FeS
precipitation
process
Elena Likosova, Stefano Freguia, AWMC
N, K Recovery using Electrodialysis
CEM
NH+
K+
CEM
AEM
Anion Exchange
Membrane (AEM)
K+
K+
NH+
NH+
NH+
K+
NH+
K+
NH+
Cathode (-)
Anode (+)
Cation Exchange
Membrane (CEM) AEM
Concentrate
K+
Wastewater
Chirag Mehta, Damien Batstone, AWMC
Resource Efficient Recycling Options
Stage 1
Carbon Removal
Nutrient Recovery
Stage 2
Nitrogen
Removal
Stage 3
Water Polishing/
Disinfection
What is Anammox?
Conventional
Nitritation/Anammox
Nitrification
NH4+
Partial
Nitritation
NH4+
0.84 O2
(42%)
2 O2 (100%)
NO3-
0.45 NH4+
0.55 NO2-
C-Source
(e.g. methanol:
2.2 kg/kgN;
COD: >5kg/kgN)
0.5 N2
Denitrification
0.44 N2 + 0.12 NO3Anaerobic ammonia oxidation
A. Joss, EAWAG
Anammox-type process scale-up
Approximately 18-24 month process for first full-scale installation
Much shorter (0-6 months) for subsequent installations
Wett & Dengg (2006)
Full-scale plants in operation
• Austria
– Strass, plus others
• Switzerland
– Zürich, 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
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
25
SRT Control - Cyclone for selecting for DEMON® Granules
MLSS
Overflow
Underflow
Nitritation/anammox Combined in
Moving Bed Biofilm Reactor (MBBR)
ANITATM-Mox
Dewatering Liquor Treatment in Zurich
Two SBR tanks; 2800m3 total volume; 1800m3/d flow; 1200 kgN/d load
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
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
Concluding Thoughts
Water recycling justified by economics and supply security
but needs to improve environmental footprint
--Energy recovery valuable for WWTP operation, plus
economic in industrial situations and/or for (bio-)products
--Nutrient recovery – needed for supply security (P) and
increasingly economics (N & K)