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WATER CONSERVATION & REUSEA CASE STUDY @ AMUL DAIRY, ANAND

Babji SrinivasanAssistant ProfessorIIT Gandhinagar

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PROCESSING UNITS

Raw milk receiving and processing (RMRD)

Ghee Section Flavoured Milk

Skimmed milk Powder plant

Milk Packaging

Powder Plant Butter Section

OVERALL WATER USAGE @ AMUL

75%

2.6%0.4%

2%

2.2%

16.25%

1.55%

CIP & floor cleaningOperational ProcessesCrate WashRailway Tanker WashCooling tower makeupBoiler feed makeupOther

Total = 1600 m3/ day

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CIP & FLOOR CLEANING

89%

4%1% 3% 3% Raw milk receiving

and processingButter

Ghee

Flavoured Milk

Milk Packaging

Total = 1200 m3/ day

BOILER FEED & COOLING TOWER

130 104 26

0% 50% 100%

Boiler FeedCondensates from PowderplantsFresh water

Condensates from Ghee section

All values in m3/day

0 20 40 60

Cooling Tower 43.535

Make up waterBolwdown rate

All values in m3/day

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PERFORMANCE INDEX

Process Units Production (m3/day)

Water used for CIP & cleaning

(m3/day)

Ratio(Water toProduct)

Milk receiving & Processing

1800 1080 0.6

Powder plant 75 27.5 0.4Skimmed milk Power

Plant55 35 0.6

Butter 75.5 45 0.6Ghee 14 9.75 0.7

Flavoured milk 25 35 1.4Milk Packaging 90 46 0.5

CIP

CIP

Make up feed

Make up

CIP & Manual Cleaning

WATER USES & EFFLUENT SOURCES

Processing Units

Cooling TowerRMRD

Butter

Flavoured milk

Ghee

Powder plant

Milk Packaging

Skimmed milk powder

Water

Boiler Section

Effluent Treatment

Plant (ETP)

WaterCondensatesWaste water

Blow down

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CTET

GH

AD 1

AD 2

AD 3

UASBAT 2

AT 2 ST

SC SpT PF AC CT

Abbreviation MeaningCT Collection Tank

ET Equalisation Tank

GH Gas Holder

AD Anaerobic Digester

AT Aeration Tank

ST Settling tank

SC Secondary Clarifier

SpT Supernatant Tank

PF Pressure Sand Filter

AC Activated Carbon

P&ID of ETP

CURRENT SCENARIO

¢ No segregation of waste water streams from different units

¢ No focus on possible reuse of treated water within the Dairy

¢ Non optimised treatment process & manual operation leading to High Energy Cost

¢ Some important parameters such as nutrient conc. not monitored and reported

¢ No regulation & utilisation of Biogas flow produced from Anaerobic Digesters

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SEGREGATION OF WASTE WATER & REUSE

Process Unit

Monitor Pollution

Level

ETP

Treatment

Water Effluent

Low

High

Reuse

PRESENT EFFLUENT FLOW SCHEME

RMRD

Butter

Powder Plant

Powder Plant

Amul 3 CIP

GheeCrate washCrate wash

PackagingMilk

Packaging

Ghee

Skimmed Skimmed milk

Powder

Amul 2

Blow down

Cooling Tower

Blow down

ETPEffluent samples Collected and analysed

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ANALYSIS RESULT

0500

100015002000250030003500400045005000 Influent to ETP

Amul 3

Flavoured

Ghee

Packaging Crate wash

Packaging CIP

Cooling Tower Blowdown

ANALYSIS RESULT

0123456789

10

pH Conductivity (mS)

Influent to ETP

Amul 3

Ghee section

Flavoured Milk

Packaging Crate wash

Packaging CIP

Cooling Tower(Blowdown)

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OBSERVATIONS

¢ Milk packaging CIP water (relatively clean) is mixed with effluent from Crate wash

¢ The effluent from Amul 3 is highly polluted due to mixing of two types (Ghee & RMRD) of effluents

¢ Effluent from cooling tower & ghee section mixed with more polluted water from Flavoured and Amul 3

SUGGESTED SCHEME FOR REUSE

RMRD

Butter

Powder Powder Plant

CIP

Ghee

Crate Crate washMilk

Packaging

Skimmed Skimmed milk

Powder

Blow down

Cooling Tower

Blow down

ETP

RO 0r MF

Reuse

Coagulation & Adsorption Coagulation & Adsorption

Reuse

Reuse for rinsing

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TREATMENT AT THE PROCESS UNITS

¢ Ghee effluent - Coagulation followed by adsorption can reduce COD by 96% (Hussain et al. , 2014)

¢ Cooling tower blow-down - Membrane filtration (MF) or Reverse osmosis has been known to reduce the conductivity and corrosive ion concentration significantly

� http://www.waterworld.com/articles/iww/print/volume-12/issue-6/feature-editorial/zld-treatment-of-cooling-tower-blowdown-with-membranes.html

� http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0314/0901b80380314edf.pdf?filepath=liquidseps/pdfs/noreg/609-02176.pdf&fromPage=GetDoc

POSSIBLE WATER SAVINGS

¢ Ghee section – Reuse may save an average 9750 litres of water used per day

¢ Cooling tower – an average of 43.5 m3 of water can be reused within the dairy per day

¢ Milk Packaging – 32 m3 of water can be reused for rinsing of the process equipment of the unit.

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EFFLUENT TREATMENT PLANT (ETP)

¢ Treats 1100 – 1200 m3 of water per day

¢ Treated water used in � Toilet flushing = 5 m3/day

� Gardening = 1000-1100 m3/day

� Filter Back wash = 20 m3/day

COST OF WATER

112.5 17506650

62040

Cost of Water in Rupees per day

Raw waterSoft waterRO waterTreatment

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STEADY STATE SIMULATION OF ETP IN SIMBA#

¢ Anaerobic digesters (AD’s ) & UASB were modelled using Siegrist digestion models

¢ The activated sludge systems (AT followed by SC) were modelled using ASM3

¢ Activated carbon unit was excluded

ETP MODELLED IN SIMBA#

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CHARACTERISTICS OF WATER AT ETP

ParametersInfluent to the

real ETP

Influent to

Virtual ETP

(SIMBA#)

Final Effluent

from real ETP

Effluent from

Virtual ETP -

PSF(SIMBA#)

pH 6.5-7.0 Not calculated 7.0-8.5 Not calculated

COD4500 - 5000

(ppm)4627 ppm 48 - 96 (ppm) 417

BOD1500 - 1700

(ppm)Not calculated 16 -33 (ppm) Not calculated

TSS 500 - 1000 (ppm) 3428 35 – 95 (ppm) 50

MODIFIED ETP IN SIMBA#

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RESULTS

Parameters Units Influent to ETP

Effluent of ETP

Effluent of modified ETP

Total suspended solids mgTSS/L 3428 50 50Volatile suspended solids mgTSS/L 2817 39.62 39.67

total COD measured mg COD/L 4627 417.1 416.5

Filtered COD (incl. colloidals) measured mg COD/L 667.5 354.8 354.5

total nitrogen measured mg N/L 194.7 43.54 21.67

TKN measured mg N/L 194.7 6.494 6.748Filtered nitrogen (incl. colloidals)

measured mg N/L 21.36 40.91 18.98

Sum of NO2 and NO3 measured mg N/L 0 37.05 14.92

Total power consumed by blowers kWh NA 686 337

No Oxygen Supply

Importance of Nitrogen Removal

Total nitrogen to an average level of 8 to 10 mg/L should be maintained before being discharged into a receiving water

Industry Range of NH4+

(mg/L or ppm)

Cokery 3300-4100

Oil refinery 450-630

Coal < 2500

Fertilizer 200-940

Diary < 625

Pharmaceuticals < 475

Wiesmann, U. (1994)

N2

NH4+

NO2-

NO

N2O

NO3-

Eutrophication Blue baby Syndrome Fish Killing

De-nitrificationOxygen Supply

No indication of N2O 26

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Oxygen Supply

New metabolic pathways for N2O and NO production in AOB supported by quantitative proteomics

C. Behera, Babji Srinvasan, K. Chandran and V. Venkatasubramanian, 2015 Chemical Engineering Journal

No Oxygen Supply

N2O Formatio

n

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NH3

NH2OH

HNO2

NO N2O

NO N2O

AMO

HAO

HAO Nor

NirK Nor

CytL

O2

H2O

• Under O2 limiting condition,alternate electron acceptors (NO2

-)and donors (unionized NH3 ) toproduce significant amounts of N2Oand NO. (using NirK and Nor)

• Nitrifier dentrification and Nitrogen-dependent are ways for N2Oproduction in AOB

Chandran et al., 2011 BST

Impact of O2 limitationImpact of excessive transient NH3 and O2

Impact of Normal NH3 loading

- - - - - >Medium Scale

Large Scale

Small Scale28

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Greenhouse gas footprint at Kralingseveer (Netherlands) WWTP

U.S. Nitrous Oxide Emissions, 1990-2011 U.S. Carbon Dioxide Gas Emissions, 1990-2011

http://www.epa.gov/climatechange/ghgemissions/gases/co2.html

Daelman et al. (2013)

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Simulation result

Anoxic Region

Yu et al., 2010, ES&T

Oxic Region 30

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MODIFICATIONS IN THE VIRTUAL PLANT

¢ The single aeration tank replaced by two tanks -anoxic followed by aerobic with optimum recycle rates

¢ The retention time of the aerobic tanks made less than the original reactors at ETP => running time of blowers reduce to half of original

¢ An optimum sludge wastage rate introduced=>optimum food to micro-organism ratio obtained in reactors

Problem Statement• To operate the nitrification process in aerobic bioreactor at optimized

operating parameter which will ensure – Improve effluent quality (NH3 1 (mg/l) )– Maintain DO level (DO 2 (mg/l))– Mitigate N2O(l) production (N2O(l) 0.001 (mg/l) )

≤

≥

≤

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How to handle these type of problem in large scale waste water treatment

Advance Control Strategy can sort out this

WEF Manual of Practice No. 29

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Extended Kalman Filter (EKF)

Updation

System model equation

Prediction

EKF is the nonlinear version of Kalman filter which linearizes about the current mean.

EKF based on 1st order linearization

Remarks• It has no optimality guarantee.• Resulting error from linearization may cause estimate divergence.

Simon, D. (2006)

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33

State Estimation by EKF

34

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1 1

3 3 rate

2 2 21 2 rate 3 rate

1 0 0

ˆmin ( ( ) ( )) ( ( )) ( ( ))aeration

M MP

SNH NH aerartion aerationu j j jJ w y k j y k j w u k j w u k j

∆= = =

= + − + + ∆ + + +∑ ∑ ∑

2 m a x

m a x

m in ra te m a x

0

0

a e r a t io n r a t e

a e r a t

O

o n

N

i

u uu

yu u

y

≤ ≤

∆ ≤≤ ≤

∆ ≤ ∆

Constraint:

Cost function:

Energy efficiency NH3Objective

36

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KEY OUTCOMES FROM STUDY ON BIO-NITROGEN REMOVAL PROCESS

¢ Mitigation of N2O(l) production along with maintaining permissible range for NH4

+ and DO can be possible by implementing NMPC algorithm.

¢ Only DO measurement is sufficient to estimate N2O(l) production as well as to help NMPC for controlling other variable.

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C. Behera, Babji Srinvasan*, K. Chandran and V. Venkatasubramanian, 2015 Chemical Engineering Journal

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FUTURE WORK

Dynamic simulation of virtual ETP in SIMBA#

Simulation studies and necessary modifications to improve bio-gas production

Implement regulatory control & Plant Wide Control accounting for greenhouse gas emissions

Parameters (C,N,P) monitoring and diagnosis techniques especially for Anaerobic digestorunits

ACKNOWLEDGEMENTS

¢ Amul Diary¢ Department of Science & Technology, India¢ Collaborators¢ Students THANK YOU…