Resource Recovery from Wastewater Opportunities … Keller - Keynote.pdfStruvite recovery unit at...
Transcript of Resource Recovery from Wastewater Opportunities … Keller - Keynote.pdfStruvite recovery unit at...
Resource Recovery from Wastewater – Opportunities and
Achievements
Water (x 100)
Organics Nutrients
Salts
What can we get from Wastewater?
Water Reuse
Bio-Energy (Organic) Fertiliser
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
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)
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.
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
• 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
Anaerobic MBR Concept
Veolia/Biothane
Key Challenges:
- Low flux – large membrane areas
- Energy for membrane cleaning
- Fouling potential to be determined
Energy Self-suffient Process WWTP Strass (Austria, A/B Process)
200,000 EP
Nutrient Removal Plant
Courtesy Bernard Wett
High Rate Aerobic Processes
Wett & Alex, (2003) WST 48(4)
HRT = 0.25h
SRT = 0.5 d
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
Thermophilic
Reactor
T > 55°C,
2d HRT
Mesophilic
Reactor
T ≈ 35°C,
10-14d HRT
Damien Batstone, Paul Jensen, AWMC
• 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
• 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
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-
PO43- in
solution
FeSx
Na2S
NaHS
Stage I: FeS
precipitation
process
Stage II:
Electrochemical
process
Elena Likosova, Stefano Freguia, AWMC
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
Resource Efficient Recycling Options Stage 1
Carbon Removal
Nutrient Recovery
Stage 2
Nitrogen
Removal
Stage 3
Water Polishing/
Disinfection
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
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
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
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
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)