Preliminary Energy Audit methodology and key performance IWA 5 th - - PowerPoint PPT Presentation

Preliminary Energy Audit methodology and key performance indicators (KPIs) in Small Wastewater Treatment Plants

IWA 13th Specialized Conference on Small Water and Wastewater Systems - Athens 2016 IWA 5th Specialized Conference on Resources-Oriented Sanitation - Athens 2016

• B. M. D’Antoni , S. Longo, E. Akkersdijk, L. Stefani, E. Parelli and F. Fatone

Supported by the Horizon 2020 Framework Programme

• f the European Union

INTRODUCTION

Introduction Goals Materials and Methods Results and discussions Conclusions

1

1% of the total electricity consumption per year of a Country.

ENERGY AUDIT and ENERGY BENCHMARKING Key Performance Indicators (KPIs) The main objective of Horizon2020 ENERWATER project is to develop, validate and disseminate an innovative standard methodology for continuously assessing, labelling and improving the overall energy performance of Wastewater Treatment Plants (WWTPs).

Cao et al., 2011 Parena et al., 2002 Foladori et al., 2010

European Normative lag

GOALS

Introduction Goals Materials and Methods Results and discussions Conclusions

2

 Comprehensive key performance indicators (KPIs)  Energy Audit methodology and Energy TOOL  KPIs Energy Benchmarking  Wastewater Treatment Energy Index (WTEI)  Energy LABELLING  STAGE Treatment classification  To Report the results of the smallest WWTP Aims of the Preliminary Methodology Aim of this study

Introduction Goals Materials and Methods Results and discussions Conclusions

3

ENERWATER METHODOLOGY

STAGE CLASSIFICATION In order to disaggregate the energy consumption data, taking into account the different processes and treatment schemes applied in municipal WWTPs, 7 stage were used.

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ENERWATER METHODOLOGY

KEY PERFORMANCE INDICATORS (KPIs) There is a clear need to establish suitable KPIs within the WWTP that allow a comparable, realistic and universal form of reporting the energy data.

STAGE CLASSIFICATION KPIs STAGE 1 kWh/m3 STAGE 2 kWh/kg TSSremoved STAGE 3 kWh/kg CODremoved , kWh/kgTPremoved kWh/kg TNremoved , kWh/kgPEQremoved STAGE 4 kWh/kg TSSremoved, kWh/kgNH4removed kWh/kg TNremoved , kWh/kgTPremoved kWh/Log reduction STAGE 5 kWh/kg TSprocessed, kWhproduced/kgVSremoved STAGE 6 kWh/kgTPremoved , kWh/kg TNremoved STAGE 7 kWh/kg VOCs removed, kWh/kg VICs removed, kWh/kg VSCs removed,

Introduction Goals Materials and Methods Results and discussions Conclusions

5

ENERWATER METHODOLOGY

ENERWATER has initially considered the application of Italian Decree 102/2014 which has recently been adopted to audit large WWTPs in Italy.

• General data of the WWTP
• (Company, Country, Size, Etcc)

LEVEL A

• Identification of each Energy Carrier
• Electricity, Diesel Fuel,Natural gas, Biogas

LEVEL B

• Identification of Functional Areas:
• Main activities, General and Auxiliary Serv.

LEVEL C

• Identification of each process and equipment

whithin the Functional Areas LEVEL D

Introduction Goals Materials and Methods Results and discussions Conclusions

6

ENERWATER METHODOLOGY

PRELIMINARY METHODOLOGY – INITIAL ASSUMPTIONS AND CONSIDERATIONS

• 1. The age and the wearing out of the equipment was not taken into account;
• 2. The nominal power of some devices was not available;
• 3. Blowers and/or Pumps with inverter can cause big deviation from the real

consumption;

• 4. Some energy consumption data of Auxiliaries and General services was not

available;

• 5. Possible overestimation of the use factor (Ratio between actual and nominal

power).

• 6. All the energy carriers were converted in kWh.

Introduction Goals Materials and Methods Results and discussions Conclusions

7

Case Studies and Audit Results

ENERGY AUDIT PROCEDURE

1 ‐ WWTP Process

scheme

2 – Influent and

Effluent characteristics

3 – Equipment

Inventory

4 – Application of

the Energy Tool

5 – Calculation of

KPIs in each stage

6 – Calculation of

Energy Performance Index

7 – Calculation of

W.T.E.I

8 – Identification

• f Energy Label in

each Stage Introduction Goals Materials and Methods Results and discussions Conclusions

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50 WWTPs

• Italy  15 WWTPs
• Spain  15 WWTPs
• Germany  20 WWTPs

20  PE < 10,000  574 PE THIS STUDY

Introduction Goals Materials and Methods Results and discussions Conclusions

Case Studies and Audit Results

 647 m3/d ESP_31 Small or not Small, that is the question

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Case Studies and Audit Results

EXAMPLE – WWTP ESP_31

CHARACTERISTICS Influent Effluent Unit BOD5 40.21±24.50 5±1.65 [mg/L] COD 106.4±38.43 25.17±5.21 [mg/L] TN 11.43±8.11 4.65±2.07 [mg/L] TP 1.51±0.82 1.21±0.32 [mg/L]

Introduction Goals Materials and Methods Results and discussions Conclusions

1 ‐ WWTP

Process scheme

2 – Influent and

Effluent characteristics

STAGE 1 STAGE 3 STAGE 4 STAGE 5

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Case Studies and Audit Results

EXAMPLE – WWTP ESP_31

Equipment kWh/d %

STAGE 1 Influent pumping 48.61 13.1% Screening 0.78 0.2% Grit removal 16.76 4.5% Storm water Tank 8.91 2.4% STAGE 3 Recycling pump 19.57 5.3% Excess sludge pump 1.18 0.3% Mechanical aerator 73.71 19.9% Mixer Anaerobic 74.25 20.1% STAGE 4 UV disinfection 94.24 25.5% STAGE 5 Thickener 6.92 1.9% Sludge press 25.13 6.8% 20% 46% 25% 9% STAGE 1 STAGE 3 STAGE 4 STAGE 5 TOOL CONSUMPTION CALCULATION [kWh/y] Real Energy Tool Calculation % ERROR Electric Energy 135,073 136,304 ‐0.9 %

Introduction Goals Materials and Methods Results and discussions Conclusions

3 – Equipment

Inventory

4 – Application of

the Energy Tool

11

Case Studies and Audit Results

Key Performance Indicators

STAGE KPI 1 [kWh/m3] 0.116 3 [kWh/KgCOD_rem] 1.17 [kWh/KgTN_rem] 15.9 [kWh/KgTP_rem] 21.73 [kWh/KgPEQ_rem] 0.149 5 [kWh/KgTS_proc] 1.51

ESP_31 1

• 1

20 100

• Introduction

Goals Materials and Methods Results and discussions Conclusions

5 – Calculation

• f KPIs in each

stage

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ENERWATER METHODOLOGY

Calculation of Energy Performance Index from KPIs How to combine KPIs?

Introduction Goals Materials and Methods Results and discussions Conclusions

m3  0.216 STAGE 1 PEQ  0.639 STAGE 3 TS  0.949 STAGE 5 ESP_31 ENERGY PERFORMANCE INDEX E % STAGE 1 14% STAGE 3 70% STAGE 5 11%

EPI Whole Plant ∗ % ∗ % ∗ % % % %

(EPI_whole) ESP_31 = 0.623

6 – Calculation of

Energy Performance Index

How to add apples and oranges? BENCHMARK

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Case Studies and Audit Results

Waste Water Treatment Energy Index The EPIs are RAW DATA GUMBEL DISTRIBUTION Probability density function PDF Cumulative distribution function CDF

x  EPI (Scale parameter) (Location parameter)

Regression of Derivative equation Numerical solution methods (maximum likelihood ‐ MLE)

Introduction Goals Materials and Methods Results and discussions Conclusions

7 – Calculation

• f W.T.E.I

0.2 0.4 0.6 0.8 1 1.2 0.5 1 1.5 2 2.5 3 0.2 0.4 0.6 0.8 1 1.2

Distribution function

• Prob. density

GUMBEL Distribution_STAGE 3

PDF CDF

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Case Studies and Audit Results

HOW TO CALCULATE THE WTEI FROM THE CDF ?  prEN 15217:2005(E) Rr  Energy performance regulation  25 – Percentile of CDF Rs  Building Stock reference  50 – Percentile of CDF 1

• (if WTEI < 1)

3 1

• (if eq.1 is > 1)

2 1

(if Rr < CDFi < Rs)

ENERGY LABELS A WTEI ≤ 0.5 B 0.5 < WTEI ≤ 1 C 1 < WTEI ≤ 1.5 D 1.5 < WTEI ≤ 2 E 2 < WTEI ≤ 2.5 F 2.5 < WTEI ≤ 3 G 3 < WTEI

Form the CDF

Introduction Goals Materials and Methods Results and discussions Conclusions

7 – Calculation

• f W.T.E.I

Waste Water Treatment Energy Index

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Case Studies and Audit Results

ESP_31 STAGE WTEI STAGE 1 2.898 STAGE 3 3.457 STAGE 5 3.167 OVERALL 3.340 Introduction Goals Materials and Methods Results and discussions Conclusions STAGE Theoretical Decrease 1 ‐ 44% 3 ‐ 50% 5 ‐ 47%

8 – Identification

• f Energy Label in

each Stage

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ACTUAL OUTLOOK

Introduction Goals Materials and Methods Results and discussions Conclusions Cable

Power Analyser Tele‐controller User Interface

CONCLUSIONS

The real-time measurements are needed for the better reliability of the methodology and related tool; The real removal efficiency is measured by samples analyses before and after each treatment stage. The definition of WTEI and energy labels (classes A to G) can support the decisions of the water utilities to best target energy saving actions to less performing WWTPs. The disaggregation of the KPIs within different treatment stages support to target the energy efficiency actions; The comparison with the Benchmark shows that theoretically the energy consumption in ESP_31 could be reduced by 44% in Stage 1, 50% in Stage 3 and 47% in Stage 5

ANKS FOR YOUR ATTENTION !!!