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

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Nutrient recovery – needed for supply security (P) and

increasingly economics (N & K)