Benchmarking of (large municipal) waste water treatment ... · 6/4/2009 · Benchmarking of (large...

EWA Workshop – Hennef 2009

Benchmarking of (large municipal) waste watertreatment plants (>100,000 PE) and sewer

systems in Austria

EWA Workshop,Hennef, 4. June 2009

Prof. Helmut Kroiss, Dipl.-Ing. Heidi SchaarVienna University of Technology

Dr. Stefan Lindtnerk2W, Environmental Technology, Development and Consulting, Vienna

Dr. Thomas ErtlUniversity of Natural Resources and Applied Life Sciences, Vienna

25.02.2010 2EWA Workshop – Hennef 2009

Table of content

• Introduction• Terminology & definitions• Benchmarking method• Results• Conclusions


The Austrian BenchmarkingSystem - Introduction

• Developed between 1999 and 2004• > 100 plants from 2,000 to 1 Mio PE were analysed• Process benchmarking – comparable cost elements

are related to clearly defined processes• Performance indicators for the identification of best

practice and benchmarks• Enables the comparison of performance indicators

for different treatment process schemes andoperating modes


Terminology & definitions

• Process indicators are related to one year of operation

• Benchmark plants are defined for yearly total, capital andoperating costs

• Benchmark plants � lowest specific costs

• For yearly total and operating costs benchmark plants have tomeet the following criteria:– Full compliance with the effluent limits (Austrian emission standards)– Compliance with defined data quality criteria (mass balance check, etc.).– Typical characteristics of municipal waste water

(e.g. COD/N ratio, no dominant influence of industrial waste water)


Process model (>100,000 PE)Inf

luent

pump

ing

mech

anica

l pre-

treatm

ent

prima

ry se

dimen

tation

biolog

ical tr

eatm

ent

gas e

ngine

exce

ss sl

udge

thick

ening

stabil

isatio

n

sludg

e dew

aterin

g

sludg

e trea

tmen

t and

disp

osal

labora

tory a

nd m

onito

ring

admi

nistra

tion

opera

tion b

uildin

g and

inf

rastru

cture

works

hops

motor

pool

1.1 1.2 2.1 2.2 2.3 3.1 3.2 4.1 4.2 I.1 I.2 I.3 II.1 II.2Process 2 Process 3 Process 4 Support process I II

Waste water treatmentInfluent pumping

mech.pre-treatmentmechanical-

biological treatmentthickening

stabilisationfurther sludge treatment

and disposalobligatoryprocesses

optionalprocesses

Process 1

Cost AccountAssociated

Mains

AssociatedSpecial

StructuresMains of

Communities

SpecialStructures ofCommunities Administration

AuxiliaryComponents

(Carpark, Workshop)Cost Process P 1 P 2 P 3 P 4 HP I HP II


Terminology & definitions

• Arrangement in groups according to the design capacity (PE)� comparable process indicators

• Process benchmark � lowest specific operating costs for oneof the processes

• No process benchmarks for capital costs - the data basis doesnot allow fair comparison

• Benchmark bands– to take data inaccuracies into account– lowest specific total yearly costs of a benchmark plant increased

by 10 %


Benchmarking method• Following the timeline of a benchmarking year, the

benchmarking process can be sub-divided into three steps:

a) Data acquisitionb) Data processingc) Exchange of experience Ja

nuar

y

September

July


Data acquisition

• Organised via internet platform(www.abwasserbenchmarking.at)

• Data transfer and communication between the stakeholdersare conducted via internet

• Operating data � updated every year by treatment plantmanagers

• Conservative data (master file data) remain stored � updatedin case of changes

• Specific accounting system to process the financial data� automatic update for continuous benchmarking


Data processing• Data quality assessment WWTP

– rough plausibility check � data within a feasible range– operating data: mass balances for COD, nitrogen, phosphorus

and total solids– financial data: variance analysis comparing data input with

previous year value• Data assessment sewer systems

– PTA Value• Computation of performance indicators

– plausibility check• Generation of a draft final report (indicators, interpretation

and conclusions regarding performance improvement)


Data Processing


Performance indicator system

Technical input- and output data, master file data (e.g. volumes, etc.)and data from process oriented cost calculation (accounting)

Processindicators

Financialindicators

Technicalindicators

Key

indicators�

Technical input- and output data, master file data (e.g. volumes, etc.)and data from process oriented cost calculation (accounting)

Processindicators

Financialindicators

Technicalindicators

Key

indicators�


Exchange of experience

• Individual consulting on site - discussion of– potential data quality problems– the draft final report

• Workshops– as a platform for the exchange of experience– learn more about the best practice– learn from the best


Costs for participating plants

• Development of internet platform � financed by theFederal Ministry of Agriculture, Forestry, Environmentand Water Management

• Participants pay for running costs (depend on the size ofthe plant)

• The yearly costs for participation (WWTP > 100,000 PE)are calculated as follows:– First year: 7,000 € + 0.01 € * design capacity in PE– Continuous: 3,000 € + 0.005 € * design capacity in PE


Participants• Sewer systems

• 1999: 52 operators with 2914 km public sewers (~4% of A.)1367 ancillary structures incl. 473 pumping stations

• 2004: 6 operators with 244 km public sewers86 ancillary structures incl. 35 pumping stations

• WWTPs:

112 different WWTPs= 42% of total capacity of all WWTPs

>20000 pe of A. (excl. Vienna)

3024212230974116112

2008200720062005200420031999WWTPs

>20000 penot taken part

Untilnow


Results Sewer Systems (1999):operating costs (€/m)

0

0

0

0

0

0

0

0

0

1

2

3

4

5

€/m

best practice

communities group 1 group 2 group 3

Figure 3: Annual O&M costs per length of sewer (excl. ancillary structures)< 15km > 40 km


• Group B are associations operating only the associated net (mostlytransport or interurban mains)

• Group C are participants operating also sewage systems of theirmember communities.

Group B

Energy39%

Personnel36%

Others3%

Residualdisposal

0,5% Material1%

ContractedService

21%

Group C

Energy21%

Personnel30%

ContractedService

44%

Others4%Material

1%Residualdisposal

0,3%

Results Sewers (1999)cost categories as

percentage of total operating costs


Results WWTPs (Group 6)–Benchmarking bands

Benchmarking bands

0

5

10

15

20

25

30

35

40

10.000 pe 50.000 pe 100.000 pe

[€/pe-COD 110]

Total yearly costsOperating costs

Oper

ating

costs

Total

yearl

y cos

ts

Group 4 Group 5 Group 6

34,4

27,525,5

10,09,5

13,6


Results WWTP (group 6)- costcategories as % of total operating costs

Personnel costs36%

Energy costs9%

Residue treatment costs20%

Material costs14%

External costs13%

Other costs8%

Personnel costs36%

Energy costs9%

Residue treatment costs20%

Material costs14%

External costs13%

Other costs8%


Results (Group 6)– Box Charts ofprocess related specific operating costs

0,00,51,01,52,02,53,03,54,04,55,0

Oper

ating

cost

[Eur

o/pe-C

OD11

0]

75%-Percentile 0,23,54,91,02,01,1Maximum 0,23,85,01,12,71,3Minimum 0,11,92,80,40,80,6Median 0,13,34,30,71,50,825%-Percentile 0,12,53,70,61,20,7Benchmark 0,11,92,80,72,70,9

optionalsupportprocess

obligatoriysupportprocess

sludgetreatmentdisposal

thickeningstabilisation

mechanical-biologicaltreatment

inf. pumpingmech.pre-treatment


Conclusions regardingperformance indicators

• ≥40% of the total operating costs for sludge treatment anddisposal

• 50 to 65% of the operating costs - independent of the actualCOD-load on the plant � significant impact of the utilisationfactor (actual load/design capacity) on the specific operatingcosts

• No correlation between treatment efficiency and operatingcosts (same treatment efficiency requirements!) �� excellenttreatment efficiency often coincides with low specific costs �quality of the staff is very important


Conclusions regardingmethodology

• Continuous benchmarking - a powerful management tool

• Comparison with the benchmarks and exchange ofexperience help the treatment plant managers toincrease cost-efficiency

• Not only a tool to enhance cost-efficiency, BUT offers theopportunity to prove excellent performance of treatmentplant operation (to public, politicians, board membersetc.)


www.abwasserbenchmarking.atBenchmarkingbereich (LOGIN):Benutzername (username): musterwasserPasswort (password): geanio

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