2 October 2019

Challenge the future

DelftUniversity ofTechnology

Wastewater treatment in the Netherlands Developments, Trends & InnovationsProf.dr.ir. Jules van Lier / j.b.vanlier@tudelft.nl

2ND Malaysia-Netherlands Water

Dialogue 2019

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High quality effluents:• Extensive C removal • Extensive N & P removal• Effluents for discharge• Minimizing combined sewer overflows

Wastewater treatment in the Netherlands: pollution prevention!

Cost-effective guaranteed provisions:• Cost-effective management• Full cost recovery by public taxes

(polluter pays)• ≈ 100% households connected• Guaranteed urban drainage

Contributing to cyclic economy:• Effluents for Reuse?• Resources from sewage?

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Biological process

Screen Gritremoval

Primarysettling Selector

Anaerobictank

Anoxictank

Aerobictank Final

clarifier

Influent Effluent

Return sludge Secondaryor Waste sludge

Optional postTreatment

Primarysludge

ThickenerSludge

DigesterBiogas

DewateringRejection water

treatment

Sludge treatment

WWTP Harnaschpolder - Delft

Removes:‘C’: BOD < 20 mg/l‘N’: < 10 mg/l‘P’: < 1 mg/l

Current standard

Basic WWTP process: activated sludge & biological nutrient removal (BNR)

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Current challenges of Sewage Treatment Plants (STPs) in NL:

- More stringent discharge criteria (EWFD):- N: 10-15 → 5-7 → 2.2 mg/L- P: 1-2 → 0.35 → 0.1 mg/L

- Energy efficiency / less fossil fuel consumption- Recovery of resources- Reduction green house gas emissions (CH4, N2O, etc.)- Less/no (?) micro-pollutants in effluent- No (antibiotic) resistant bacteria / pathogens in effluent- Etc.

Current and upcoming effluent restrictions set the boundary conditions for new developments (like resource recovery)

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Aeration tank

Bar screen

Sandtrap

Sedim.Tank

Sedim.Tank

Sludge treatment

INFLUENT

EFFLUENT

• Sludge • digestion

Thickeners

less energy for nitrification!

air / energy

N2

Anammox CHP

Conventional STP with Anammox in sludge reject water line:

NH4+ + NO2

- → N2 + 2H2O(3 x less energy)

Enhanced N/P removal?

Micro pollutants?

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‘mainstream’ Anammox

Bar screen

Sandtrap

Sedim.Tank

Sedim.Tank

Sludge treatment

INFLUENTEFFLUENT

• Sludge • digestion

Thickeners

air / energy

N2

Anammox CHP

Poly electrolytes + FeCL3: Enhanced COD & P-removal

A stage

aeration

A-B system with Anammox as B stage

Pilot reactor STP Dokhaven, Rotterdam

Results so far:Below 15oC problems with process stability

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More efficient WWTP: NEREDA

TUD-RHDHV: First full scale May 2012

Advantages: 35-45% reduction energy consumption! 75% reduction space requirement! Decreased investment and operational costs Highly efficient for BOD, N, P Bio-polymers of excess sludge mass: potential

resource

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influent

screening grit chamber

sludge drying bedreuse

effluentU A S B

biogas use

watersludgebiogas

- Pond / Lagoon- Trickling filter- Activated sludge- Wetland- RBC- etc.

At temperatures > 20oC: Anaerobic sewage treatment!

Post treatment

Residual BOD, N / P?

COD/BOD -removal

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Rio Claro STP

Piracicaba STPFull-Scale Experiences in Brazil

Sao Paulo, Brasil

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Nova Odessa – SP, BrasilCapacity: 50.000 inhabitants

Combined anaerobic-aerobic treatment in single reactor: BIOPAQ®UBOX REACTOR

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‘

RAW SEWAGE

AIR

FLARE

TREATEDEFFLUENT

ANAEROBIC

BIOGAS WITHOUT

H2S

1

AEROBIC

3

2

4

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1. INFLUENT DISTRIBUTION

2. 3-PHASE SEPARATOR

3. AERATION SYSTEM

4. HIGH-RATE SETTLER

5. BIOGAS SCRUBBER

BIOPAQ®UBOX REACTORWorking principle

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Resource Recovery from Waste Water?!“Green Deal” Water Authorities – Ministry:

Bound N(NH4

+)

Phosphate

Bio-Plastics

Energy

Proteins / biopolymers

Fibres

Water

??

MetalsSulphur

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Resource Recovery from Waste Water?!

Energy

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AEROBIC

Heat loss

Sludge, 30-60 kg

Effluent,2-10 kg COD

Influent +

Aeration(100 kWh)

Activated sludge: Energy Recovery via Sludge Digestion!

Energy recovery via sludge digestion

1 kg sludge ≈ 1.5 kg COD≈ 5.7* kWhtheor

45 kg sludge ≈ 255 kWhtheor

≈ only 30-50% ? biodegradable

1 kg COD (organic matter)≅ 13.8 MJ (hhv)≅ 3.8* kWhtheor

Note: conversion efficiency: - biogas motor: 30-35%- CHP: 40%- SOFC: 80-85%

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Enhancing Energy Recovery via Digestion??• More efficient energy conversion techniques: CHP/SOFC

• Green gas production: gas-grid injection / automotive?

• Better operation existing sludge digesters (mixing / feeding)

• Pre-treatment of excess sludge (Pressure, Temp., OH-, enzymes, etc.: more CH4 per ton sludge! (e.g. Cambi, Sustec, etc.)

• Energy from residue: pyrolysis, gasification, sludge drying

• More “energy” to sludge digesters

Increase primary sludge production

External sludge: co-digestion?

Others?

- Total NL sewage sludge: 1,500,000 ton excess sludge/y (22-23% dry weight)- Incineration costs: up to 500 € / ton DS (≈ 175-200 x 106 €/y)

Dried sludge (90% DS): 10-16 MJ/kg (lignite: 10-20; petrol: 40)

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Anaerobic WW Treatment at Industry: Energy factory!

Energy recovered:17 ton COD x 0.85 (eff) x 3.8 MWh* x 0.9 lhv x 40% CHP eff. = 20 MWh-e/day ≈ 0.8 MW powerplant

No energy consumption: Assuming ≈ 1 kWh-e/kg CODremoved in activated sludgeSaved: 17 ton COD x 0.85 (eff.) = 15 MWh-e/day

Total energy benefit: 22 + 15 = 37 MWh-e/day≅ 3300 €/d (with 0.09 €/kWh), or 1.200.000 €/year

Energy content 1 ton COD ≈ 13.8 GJ ≈ 3.8 MWh

Coal powered electricity plant: 0.86 ton CO2/MWh-e

Total CO2 emission reduction: 19 (renewable fuel)/0.33 + 39 (prevented) = 96

ton CO2 /day≅ 380 €/day (with 20 €/ton CO2), or 140.000 €/year

Reducing the carbon footprint:

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Empty Fruit Bunch Solar Thermochemical Reactor:Gasification (syngas) / enhanced conversion

Palm Oil Waste to Fuel! PhD Candidate: Saqr Al-Muraisy

Palm Oil Mill Effluent

POME:

EFB

AnCMBR Reactor: high quality effluent

biogas

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Resources from Wastewater Treatment PlantsPhosphate

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P removal? ↔ P Recovery!!Formation of MAP (struvite)

MgOaq + NH4+ + PO4

- MgNH4PO4 . 6H2O [MAP]

Slow release fertiliser

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P recovery via struvite precipitation from AD sludge reject water

Struvite…Mg NH4.PO4.6H2O

Problem becomes a resource!

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P recovery in Amsterdam STP

STPAmsterdam

Value of this struvite??

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Resources from Wastewater Treatment Plants

Bound N(NH4

+)

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Ammonium: energy-based nutrient So far: NH4

+ merely destructed (at expense of fossil energy): - Nitrification/denitrification: 53 MJ/kg-N- Anammox: 16-18 MJ/kg-N- Theoretically available energy in NH3: 16 MJ/kg-N

Recovery of the nutrient NH4+?

Growing interest for N recovery from concentrated N-streams- Direct reuse: manure - Stripping and recovery as (NH4)NO3? (NH4)2SO4?- Pre-cursor for proteins?- Ferti-irrigation: use of treated sewage in irrigated agriculture

NH3 / NH4+ a scarce resource?

Recovery sustainable?

Ammonium production (Haber Bosch): 1910: ≈ 100 MJ/kg N2019: ≈ 25-30 MJ/kg N

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NH3 Fuel

Electrons

N2 + H2O

NH3 cracking

H2 oxidation

O2 reduction

O2 depleted

air

Air

O2- migration

ElectrolyteAnode Cathode

Electrical energy production

Thermal energy production

Energy content of ammonia*:• 4.8 kWh/kg-NH3* Gibbs Free Energy of ammonia oxidation at T = 750 °C

Performance SOFC:• Operational temperature: 650 – 850 °C• Electrical efficiency: 50%• Thermal efficiency: 35 – 45%

Fuel requirements:• Gaseous• 10% NH3 (90% water)• No oxidants (H2S, Cl2, O2)• No siloxanes

Solid Oxide Fuel Cell: Energy Recovery from NH3

(SOFC)

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Resources from Wastewater Treatment Plants

Water

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• Treated sewage is a reliable water source (≈ constant quality)• Potential water source for agriculture, industry, households (?)• With adequate treatment of concentrate: concomitant

accomplishment of current and future effluent (FWD) criteria

WWTP Emmen

DOWTerneuzen

Use of Treated Sewage

Industry examples, The Netherlands

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Industrial AnMBR for Water Reclamation

MF / UF RO

Coupling AnMBR to RO:high-rate water reclamation / minimized biofouling

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Memthane® + ROFull scale plants – Dairies (South Africa)

• 2 Memthane® + RO plants • Currently preparing at start-up and

commissioning• Design COD = 9,000 mg L-1

• TSS = 2700 mg L-1

• FOG up to 1,850 mg L-1

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Resources from Wastewater Treatment Plants

Bound N(NH4

+)

Phosphate

Bio-Plastics

Energy

Proteins / biopolymersFibres

Water

??

MetalsSulfur

Check sustainability…!!

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Thanks for your attention!

Questions??

Acknowledgement:colleagues, students, cooperating companies!