Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Benchmarking of Municipal Wastewater Treatment Plants

LWWTP LWWTP -- PraguePrague 20032003

Stefan LindtnerStefan Lindtner, , Helmut KroissHelmut Kroiss & & Otto NowakOtto NowakInstitute Institute forfor WaterWater QualityQuality and and WasteWaste MangementMangement

ViennaVienna University of TechnologyUniversity of Technology

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

What is “Benchmarking” ?

• Benchmarking is the process of identifying and understanding practices from other organisations to help your organisation improve its performance.

• Benchmarking is not only a comparison of actual costs with “benchmarks”,

• but also a comparison of “business processes” with the aim ofthe implementation of enhancements.

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Learning from the best

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Benchmarking in wastewater business

• Within the wastewater businessthere are processes which do not exist elsewhere (sewer operation, wastewater treatment),

• some exist in other branches too (administration, management, ...).

This presentation will focus on wastewater treatment related processes with a prevailing engineering aspect.

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Benchmark Actual value

“Savingspotential”

Influences on costs due tosite-specific particularities

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Process definition for comparisons

wastewater treatment plant ae

ratio

n

biog

as u

tilis

atio

n

P p

reci

pita

tion

……

……

.

mechanical-biological wastewater treatment

mechanicalpretreatment(screening, degritting)

sludge thickening & stabilisation

enhancedsludge

treatment(dewatering,

reuse/disposal)

process 1 process 2 process 4process 3

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Development of Performance IndicatorsAcquisition of Technical Data

( collection / survey of data)consultants

Process Indicators

Sludge thickening & stabilisation

Enhanced sludge treatment (& disposal)

Mechanical-biological treatment

Mechanical Pretreatment

Capital and operating costs

Data Quality Assessment

Cost accounting

Process Performance Indicators

university

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Data Quality Assessment by means of Mass BalancesAngegeben wurden 146 kWh/d 96 kWh/d Steuerung / Regelung Simultanfällung

Berechnet wurden 49 kWh/d Zeit-Pause (variabel)Denitrifikation Fe-II-sulfat

intermittierend 77000 (kg/a)

CSB= 1857 kg/d

Nachklärbecken CSB= 124 kg/d668 m³ A= 1413 m²

V= 4525 m³CSB-Entfernung 28%

Flächenbelüftung (4794 m³)

CSB= 587 kg/d

Angegeben wurden 52 kWh/d CSB= 679 kg/dBerechnet wurden 88 kWh/d

Konditionierungsmittel(1000kg/a)

CSB= 483 kg/d CSB= 68 kg/d

CSB= 552 kg/dCSB= 679 kg/d

CSB= 576 kg/dbeheizter Faulbehälter

CSB= ???

CSB= 577 kg/d

V= 97 m³ V= 2356 m³

Eindicker

O2-Sonde

t-TS= 31,8 d

CSB= 679 kg/d

TS= 4,4 kg/m³V= 4794 m³

Vorklärbecken

MÜSE

FackelHeizung

1283 kWh/dAngegeben wurde

Berechnet wurd156 kWh/d

2696 (m³/a)

668 m³0 (m³/a)

CSB-Entfernung 28%

Rechenbelüfteter

Längssandfang

CSB= 2096 kg/dkeine

Rechengutwäschekeine

Sandfangutwäsche CSB= 50 kg/d

Fettanfall (23 m³/a)

Fettübernahme (10m³/a)

CSB= 5

AngRechnegutanfall (62m³/a) Sandfangräumgut (55m³/a) Be

97 kWh/d

CSB= 577 kg/d

Polymer 3,7 h/d CSB= 577 kg/d2000 (kg/a)

Siebbandpresse19m³/h bei 3% TS 161m³

keine Kanalräumgutübernahmestation

Übernahmestation (Fäkalien/Senkgruben)

Nacheindicker

V= 97 m³

740 kgTS/d landwirtsch. Verwertung entwässerter Schlamm,

Schlammverwertung und Entsorgung

Eindicker

Vorklärbecken

Q TS CSB N P

Probenahme

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Process Indicators for Operating Costsp.e.(COD110) ⇔ p.e.(Ntot11) ?

B etr iebsko s ten

R2 = 0.87

Mio

5 Mio

10 Mio

15 Mio

20 Mio

25 Mio

30 Mio

0 20,000 40,000 60,000 80,000 100,000 120,000

EW -Nges11

Nges. gemessen und

P lausibilität gut bzw . mittel

St ichprobe=40

B etr iebsko s ten

R2 = 0.85

Mio

5 Mio

10 Mio

15 Mio

20 Mio

25 Mio

30 Mio

0 20,000 40,000 60,000 80,000 100,000 120,000

EW -C S B 110

operating costs operating costs

p.e.(Ntot11)p.e.(COD110)

decided: p.e.(COD110) as Mean Yearly Load ⇒ MYL-COD

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Process Indicators

Capital costs Operating costs Yearly costs

Total Standard designload (SDL-COD) MYL-COD

Process 1

Process 2

Process 3

Process 4RDL-COD

Mean yearly load (MYL-COD)

Real design load(RDL-COD)

SDL-COD

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Criteria for “Benchmark Plant” (“best practice”)

Criteria regarding operating & total yearly costs:

• In compliance with current treatmentefficiency requirements (emission standard)

• Sufficient data quality

• Typical municipal wastewater characteristic as COD/N ratio

These criteria are not relevant for capital costs !

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Definition of Benchmarks

The Benchmarks are represented by the plants- with the lowest specific costs - that meet the “criteria” for benchmarks.

Benchmarks have been defined- for the “yearly costs” (capital & operating)

- for the capital costs

- for the operating costs and- for the operating costs of each

of the four processes (1 … 4).

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Specific operating costs [Euro/(pe(COD110).a)]

10

20

30

40

Euro

/ [p

e-CO

D11

0*a]

N/COD = strong industrial influence 22

19 16

13 10

No compliance Plants with simultaneous stabilisation

70

60

50

BM = Benchmark

0

BMBM BM

N/C

OD

BM BM

N/C

OD

BM

Group 1 Group 2 Group 3 Group 4 Group 5

< 5,000 < 12,000 < 25,000 < 50,000 > 50,000 p.e.(COD110)

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

“Benchmark-Band” for operating and total yearly costs

p.e.(COD110)

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00Euro/(p.e.(COD110)*a)

Benchmark-Band total yearly costsBenchmark-Band operating costs

2219

16 1310

50,0005,000 12,000 25,000Group 1 2 3 4 5

150,000

263535

66

71

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Operating costs related to the defined processes

wastewater treatment plant ae

ratio

n

biog

as u

tilis

atio

n

P p

reci

pita

tion

mechanical-biological wastewater treatment

mechanicalpretreatment(screening, degritting)

sludge thickening & stabilisation

enhancedsludge

treatment(dewatering,

reuse/disposal)

≈ 10 % ≈ 45 %operation costs (percentage)

≈ 45 %

……

……

.

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

0,0

0,5

1,0

1,5

kWh/kg-CODin

Group 1 Group 2 Group 3 Group 4 Group 5 Median aeration

No compliance

46 plants with fine bubble aeration

Median: 0.54 kWh/kg-CODin

17 plants with surface aerationMedian: 0.61 kWh/kg-CODin

Specific Energy Consumption for Process 2

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Representativeness of the Project for all Austrian municipal WWTP

Austria totalmio. p.e.-design 1.0 6.1 4.6 3.2 4.5fraction of p.e.-design 5 % 31 % 24 % 17% 23 %

included in this project:0,7 % 24 % 43 % 27% 0 %

25,000

50,000

p.e.

-des

ign

Group 1 Group 2 Group 3 Group 4 Group 5

5,000 ÷ 50,000 50,000 ÷ 200,000≤ 5,000

200,000 ÷

500,000

200,000

175,000

150,000

125,000

100,000

75,000

>500,000

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Summary and ConclusionsThe Benchmarking method developed is universally applicable to municipal WWTP from 5,000 to 500,000 p.e.( Final Report on the Internet: www.oewav.at )

“Benchmark-Band” for the total operating costs ranges between 10 €/(p.e.(COD110).a) for group 5 (> 50.000 p.e.)

and 22 €/(p.e.(COD110).a) for group 1 (< 5.000 p.e.)Operating costs related to processes: for Mech.-biol. treatment & Sludge stabilisation ≈ 45 %,for Mech. pretreatm. & Enhanced sludge treatment ≈ 55 %No correlation was found between operating costs and treatment efficiency

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

Questions ?

Vienna University of TechnologyINSTITUTE FOR WATER QUALITY AND WASTE MANAGEMENT

ProspectsThe project presented was only the starting point for the cost reduction process and needs further effort Adaptation of the method to smaller and larger plants

Internet platform - data collection

- data evaluation- comparison of performance indicators (PIs)

Discussion of the results in further workshops