FULL SCALE DEMONSTRATION OF ENERGY POSITIVE SEWAGE ...

FULL SCALE DEMONSTRATION OF ENERGY

POSITIVE SEWAGE TREATMENT PLANT

CONCEPTS TOWARDS MARKET PENETRATION

Funded by the Horizon 2020

Framework Programme of the European Union

Grant agreement No. 641661

YOUR FLUSH, OUR ENERGY

Christian Remy

Kompetenzzentrum Wasser Berlin

07.07.2017, POWERSTEP summer school

Assessment of full plant concepts using the life cycle

perspective

Christian Remy, KWB

POWERSTEP is funded under the European Union Horizon 2020 Framework Programme.

Grant Agreement No. 641661

1) Introduction to life cycle tools

2) Life Cycle Assessment (LCA) Method

Step-by-step procedure

Example: POWERSTEP

First results

3) Life Cycle Costing (LCC)

4) Conclusions

Content

3



• Goal: sustainability assessment of entire WWTP schemes: Environmental impacts

Economic impacts

(Social impacts)

• Challenge: How to integrate pilot data from different modules

into full treatment schemes?

How to assess them in a holistic framework? • Effects upstream and downstream

• Trade-offs

• Different effects (e.g. energy demand, water quality, …)

Assessing WWTP schemes

4



• Elements of the life cycle: Abstraction of resources

Manufacturing

Distribution and transport

Use phase

End of life (disposal)

• Many effects will not be on-site, but “hidden” in the life-cycle of processes!

• Different perspectives: “Cradle to grave”: Resources End of life

“Cradle to gate”: Resources Manufacturing

“Cradle to cradle”: Resources End of life Recycling

Using the life-cycle perspective

5



• Environmental: Life Cycle Assessment = LCA Assessing potential effects of products or systems

on the environment

Developed since 1980s, started with industry products (e.g. “glass bottle vs. tetrapak”)

Method defined in ISO standards 14040/14044 (2006)

• Economic: Life Cycle Costing = LCC

Time-dependent cost calculation for investment, operation, and dismantling of systems

Often: CAPEX + OPEX calculation, no dismantling

• Social: Social Life Cycle Assessment = social LCA

Working conditions

Social effects of products and systems

Life-cycle based tools for assessment

6



• Goals: Assessing potential environmental impacts of a product,

process or system

Accounting related emissions and resource usage

Quantifying the environmental impacts for comparative assessments (e.g. different processes)

• What LCA is not capable:

Predicting actual local effects of a system on the environment (“Environmental Impact Assessment”)

Prooving absolute sustainability of a system (only comparing different scenarios)

Taking decisions (only informing people!)

Life Cycle Assessment (LCA)

7



Definition of LCA method in ISO standards

8

Framework of LCA

Iterative process

Critical review by experts

Definition of goal and scope

Life cycle inventory

Impact assessment

Interpretation

• System functions and boundaries

• Scenarios + data quality

• Collection of process data

• Setup of substance flow model

• Calculation of indicators

• Normalisation + weighting

• Discussion of results

• Sensitivity analysis

ISO 14040/44

Mandatory for comparative studies

disclosed to the public!



Goal and scope: system boundaries

9

System boundaries

Main line of WWTP

Effluent to surface water

(COD, N, P)

Raw wastewater

Electricity Infrastructure

Centrifuge Disposal Truck

Return load

CHP Biogas

Heat

Chemicals Fuels

N fertilizer

Digestor

Direct air emissions: CO2 fossil, N2O, CH4, NH3, …

Sludge

Electricity + heat Natural gas



• Important: functional equivalency between scenarios: “cleaning raw wastewater from 100’000 pe to EU standards”

“removing 1 kg of P from wastewater”

“generating 1 MWh of electricity”

“generating 1 kg of nitrogen fertilizer”

• Functional unit for comparison:

Per influent wastewater load (“per peCOD and year”)

Per influent volume (“per m³”)

Per kg of pollutant removed (“per kg P removed”)

Per kg of resource recovered (“per kg P recovered”)

• For POWERSTEP:

Goal and scope: functions and units

10

Functional unit: „per peCOD and year“



• Setup of scenarios for comparison: Reference (e.g. normal WWTP as benchmark)

New scenarios A, B, C, … (with same functionality!)

• Accounting for secondary products (e.g. electricity, heat, biogas, fertilizer):

System expansion (= adding products)

Avoided burden (= crediting products)

Goal and scope: scenarios

11

A B

(+ E)

E*

A B

(+E)

- E* Expansion Credit

POWERSTEP



Sc1: Defining full WWTP schemes

12

• Screening of potential schemes with energy audit tool OCEAN (Veolia)

• Analysing electricity balance and comparing to benchmark (“best practice” standard WWTP)

• Select most-promising schemes for in-depth analysis with life cycle tools!

Screening

of potential

schemes

(>> 40)

Compare to

benchmark

Detailed analysis

with LCA + LCC


Grant Agreement No. 641661 13

Sc2: Energy balance for conventional WWTP (benchmark, optimised loading)

23,2

26,4

20,121,7 21,6

25,2

18,520,720,4

23,5

18,321,0

8,5 9,7

4,8 5,4 5,16,5

1,4 2,5

-25

-20

-15

-10

-5

0

5

10

15

20

25

30D

ilute

d

Dilu

ted

+ T

N =

18

Co

nce

ntr

ate

d

Co

nce

ntr

ate

d +

TN

= 1

8

Dilu

ted

+ T

N =

18

Dilu

ted

+ T

N =

15

Co

nce

ntr

ate

d +

TN

= 1

8

Co

nce

ntr

ate

d +

TN

= 1

5

Dilu

ted

+ T

N =

13

Dilu

ted

+ T

N =

10

Co

nce

ntr

ate

d +

TN

= 1

3

Co

nce

ntr

ate

d +

TN

= 1

0

Small WWTP = 5,000 pe Medium WWTP = 50,000 pe Large WWTP = 500,000 pe

Ele

ctri

city

de

man

d o

r p

rod

uct

ion

[kW

h/(

pe

*a)

]

Others

Sludge treatment

Activated sludge

Primary treatment

Electricity produced

Total gross demand

Net electricity balance

Self-sufficiency: 63-92% = best practice!!



Sc3: Modules for OCEAN screening

14

A-stage (C extraction)

Primary clarifier

Chemically enhanced primary clarifier

High-rate CAS

High-rate MBBR

(Coagulation + flocculation ) + Microscreen

UASB

DAF CAS: conventional activated sludge, SBR: sequencing batch reactor, MBBR: moving bed biofilm reactor, UASB: upflow anaerobic sludge blanket, DAF: dissolved air flotation, CHP: combined heat and power, SRC: steam rankine cycle, ORC: organic rankine cycle

Biogas valorisation

CHP plant

SRC + ORC

Biological methanation

Sidestream treatment

(NH4)

Nitrification + denitrification (SBR)

Nitritation

Deammonification

Membrane stripping

B-stage (N removal)

Nitrification + denitrification (CAS)

Mainstream Anammox (1-stage MBBR)

Energy balance compared to benchmark?



Sc4: screening of A stage for medium WWTP

15

Work in progress!



• Data for process modelling (“foreground”): Data from pilot plants and case studies

Set up substance flow model for WWTP in LCA software UMBERTO NXT LCA

Complement with data from previous projects (e.g. for sludge disposal)

Validate data with partners to assure data quality!!

• Data for electricity, materials, … (“background”): LCA database ecoinvent v3.3

Datasets for >6000 processes

Geographical (e.g. CH, EU, …) and time (e.g. 2015)

Regular updates available (e.g. power mix)

Goal and scope: data sources and quality

16



LCA model in UMBERTO

Water line

Sludge line

Sludge disposal

CHP

Background processes

Mass flows are 100% calibrated to OCEAN data!



Details of LCA model

18

• Static substance flow model (Volume, TS, COD, TN, TP) representing annual mean operation

• Model structure with parameterized process modules: Electricity and chemicals demand as f(input)

Elimination of substances via efficiency of removal (%)

Emissions in relation to input load (e.g. % of Nin as N2O)

• Important to-dos:

Close mass balances

Validate process data with partners

Validate process flows with your experience! (reasonable??)



LCA model in UMBERTO



LCA results: environmental indicators

20

• Cumulative energy demand (fossil + nucl)

• Global warming potential (CO2,fossil, CH4, N2O)

• Eutrophication Freshwater (P)

• Eutrophication Marine (N)

• Acidification (SO2, NOx, NH3)

• Ecotoxicity, human toxicity (metals, organics, …)

• Water footprint

• Land use

• ….

• DIFFERENT LCIA indicator systems available!

POWERSTEP



Midpoint vs. endpoint indicators

21

© ReCiPe 2016

Midpoint indicator

- Mostly direct

environmental

effects

- Physico-chemical

correlation

- More transparent

to follow cause

and effect

- Cannot be

aggregated

- Difficult to interpret

(trade-offs?)

Endpoint indicator

- Modelling damage

to human health,

ecosystems and

resources

- Less transparent

to follow cause-

effect chain

- Aggregation of

different effects,

but more

uncertainty!

- More simple to

interpret

POWERSTEP



Reference WWTP: energy and CO2-eq

Primary energy demand Global warming potential



Reference WWTP: water quality

Marine eutrophication Freshwater eutrophication



LCA results of POWERSTEP??

24

• Screening process is on-going no LCA results for POWERSTEP schemes

• Modelling from previous projects indicate high benefits in energy and CO2-eq for POWERSTEP concept:

„ENERGY-POSITIVE WWTP“

Not included: - Sludge dewatering - Sludge disposal - Return load - Auxiliary demand

No full LCA!! Results tbc in POWERSTEP…



• Trade-off between carbon extraction and nitrogen removal? (electricity vs. adding C source)

• Trade-off between energy savings and enhanced N2O emission? (~ factor 300x in CO2-eq)

• Return load?

• Sludge disposal? (= more primary sludge, more Fe sludge, …)

• Effect of POWERSTEP in different countries? (e.g. power mix in GER, AT, DK, FR)

• …

Questions for LCA in POWERSTEP

25



• Life Cycle Costing = time-dependent calculation of costs for investment, operation and dismantling over the life cycle

• In WWTP studies: ~ cost calculation Investment costs (CAPEX), often as annuity

Operational costs (OPEX)

Dismantling excluded!

• LCC and LCA can use the same approach: Definition of system boundaries, functions, functional unit,

scenarios, data quality

Input data (e.g. demand for electricity, chemicals, disposal, …)

Some data has to be explicitly generated for LCC (e.g. manpower, investment cost, …)

Life Cycle Costing - method

26



Basic data for cost calculation

27

Basics

Value added tax 19%

Planning cost 18% of Invest

Annuity 3%

Lifetime

Construction 30 a

Machinery 12 a

Electro + ICA 10 a

Energy

Electricity 0,132 Euro/kWh

Add-on for auxiliary 0%

Chemicals

Conc [%] Density [kg/m³] Euro/t

FeCl3 40 1400 175

PAC (Al) 6% 140

Polymer 100 1000 3500

NaOH 32 1360 200

H2SO4 37,5 1280 240

Citric acid 100 1240 2020

HCl 25 1125 230

NaOCl 12 1220 980

MemX 9280

Powdered AC 100 425 1500

Liquid Oxygen 100 1141 110

Microsand 100 2650 150

Service water 100 1000 2,5

Maintenance

Construction 0,5 % of Invest

Machinery 2,5 % of Invest

Electro + ICA 1 % of Invest

• Basic assumptions (VAT, annuity, …)

• Prices for energy and chemicals

• Lifetime of investment (!!)

• Maintenance and spare parts

• Insurance

• Labour costs

• …



Example: data for CAPEX and OPEX

28

Investkosten

Anlagen Bau Maschinen Membran Elektro Gesamt

Baugrube 3903710 3903710

Membranhalle 9542051 6346000 15888051

Mikrosiebung 300µm 0 1644000 1644000

Primärfiltration 0 20959500 20959500

Sekundärfiltration 0 4003500 4003500

Membranen 0 10176000

Leitungen 0 502050 502050

FM+Dosierung 0 667000 667000

Netztechnik 0 1273027 1273027

Sonstiges 1016525 2878525 3895050

Summe 14462286 30654575 10176000

7619026,95

5 62911888

Summe + NK 17065497 36172399 10176000 8990452 72404348

Summe Brutto 20307942 43045154 12109440 10698638 86161174

Anteil [%] 24 50 14 12 100

Abschreibungszeitraum (a) 30 12 7 10

KFAKR 0,0510 0,1005 0,1605 0,1172

Betriebskosten

Energie kWh/m³ kWh/a Euro/kWh Euro/a

Siebung + Coagulation 0,005 434697 0,132 57380

Membrananlage 1. Stufe 0,081 7042099 0,132 929557

Membrananlage 2. Stufe 0,076 660740 0,132 87218

Sonstiges 0,002 173879 0,132 22952

Nebenaggregate 0

Summe 0,096 8311416 0,132 1097107

Chemikalien + Material Euro/t t/a Euro/a

Fällungsmittel FeCl3 (40%) 175 5030 880262

NaOH (32%) 200 94,7 18938

H2SO4 (37.5%) 240 1078,6 258868

HCl (25%) 230 10,9 2503

Citronensäure 2020 6,2 12505

NaOCl (13% aktives Cl) 980 48,0 46992

MemX 9280 20,6 191490

Summe netto 1411557

Summe brutto 1679753

Personal Anzahl h/a Euro/h Euro/a

Techniker 4 1530 52 318240

Meister 0,25 1530 72 27540

Ingenieur 0,50 1530 92 70380

Summe 416160

Wartung Bau Maschinen Elektro

Wartung bez. auf Investkosten

(%/a) 0,5 2,5 1

Summe 72311 766364 76190 914866

Schlammentsorgung kg/d Euro/t Euro/a

Fe-Schlamm (2.5 g TS/g Fe) 4764 97 168663

TS-Rückhalt 1214 97 42992

Summe 211655

Investment costs

Lifetime

Electricity

Chemicals

Labour

Maintenance

Sludge disposal



CAPEX + OPEX for WWTP tertiary treatment

29

5,8 €-ct/m³ 6,5 €-ct/m³

11,7 €-ct/m³

13,8 €-ct/m³

• Comparing annual costs

• CAPEX or OPEX dominant?



“Real” LCC as time-dependent cost function

30

• Timing of cash flow demand?

• Break-even points for comparison?

• Future inflation? annuity? …



• Done by Krüger A/S (engineering company!)

• Data from project partners: Aggregates, PID, piping

Investment costs for special parts

Flow and mass balances

Electricity and chemicals demand

Waste disposal

Manpower

…

• Calculation of CAPEX and OPEX

• GOAL: POWERSTEP with comparable cost, but higher energy efficiency!

Cost calculation in POWERSTEP

31



• Goal: sustainability assessment of WWTP schemes: Environmental impacts

Economic impacts

(Social impacts)

• Life cycle tools are useful to assess WWTP: Holistic perspective (= all relevant parts of the system)

Systematic method to follow

Quantitative results for comparison

Trade-offs can be revealed

• Transparency is the key to credibility sound argumentation and good reporting is essential!!

Conclusion: assessing WWTP schemes

32



LCA and LCC: useful in a complex world…

33

Raw waste-water

Duckweed bioreactor

Biogas 60% CH4

Sludge liquor

Sludge >70% of COD

Solids

Electricity

Biofiltration or coagulation/filtration

Effluent

Biomass

Membrane stripping

Nitrogen management in side stream

Post-treatment

Carbon extraction for energy recovery

Fe, Polymer

CHP plant

Anaerobic digestor

Fertiliser

Heat Heat

Nitrogen removal in main stream

Heat

Biogas valorisation + efficient energy management

Biogas 90% CH4

H2

Nitritation + anammox

Low-load 2nd stage High load 1st stage

Microsieve

Deammonification

Advanced control

Steam Rankine Cycle

Thermoelectric generator

Power-to-gas

Electrolyser

Smart grid management

MORE

SUSTAINABLE

???


Grant Agreement No. 641661 34

Thank you for your attention!

www.kompetenz-wasser.de [email protected]

POWERSTEP is an innovation action project supported by the European Union under the Horizon 2020 Framework Programme in contract #641661, duration: 01/07/15 – 30/06/18

FULL SCALE DEMONSTRATION OF ENERGY

POSITIVE SEWAGE TREATMENT PLANT

CONCEPTS TOWARDS MARKET PENETRATION

Funded by the Horizon 2020

Framework Programme of the European Union

Grant agreement No. 641661

YOUR FLUSH, OUR ENERGY

Christian Remy

Kompetenzzentrum Wasser Berlin

07.07.2017, POWERSTEP summer school

FULL SCALE DEMONSTRATION OF ENERGY POSITIVE SEWAGE ...

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