WATER “PROCESSING”:DYNAMICS, METRICS, SENSORS

Diego RossoUniversity of California, IrvineDepartment of Civil & Environmental EngineeringDepartment of Chemical Engineering and Material ScienceWater-Energy Nexus Research Center

Clean Water: Technical Challenges and Opportunities WorkshopHilton Dallas Lincoln Centre - July 10/11, 2017

ENERGY & WATER PROCESSES

A: SUBSTITUTIONB: REGENERATIONC: REDUCTION

Grant et al (2012) Science 337(6095) 681-686

The Iceberg Paradigm

www.sedonakarma.com

CapEX

OpEX

CLOSING THE WATER PROCESSING CYCLE

ENERGY FOOTPRINTfrom

headworkstertiary effluent

secondary effluent

secondary clarifier

primary clarifier

sludge thickener

anaerobic digester

to disposalbiogas

wastewater lines

solids lines

tertiary treatment

activated sludge

$$$$$$$$$$$$$$$$ $$

$$$$

heating

Landfill (incineration)

aeration disinfection

Aeration cost = 45-75% of plant energy (w/o influent/effluent pumping)Rosso and Stenstrom (2005) Wat. Res. 39: 3773-3780

Dewatering

Aeration

Digestion

Other

Chemicals Pumping

(WEF MOP32, 2009)

ENERGY & WRRF

49%

Many forms of energy in WW

Adapted from Wett (2016) IWA/WEF WWTmod

POWER

INFLUENT

PRIMARYSETTLER

THICKENING

DIGESTER

DEWATERING

ACTIVATEDSLUDGE

CHP

EFFLUENT

EXHAUST

RESIDUES

Kinetic EnergyCaloric EnergyPotential EnergyThermal EnergyElectric Energy

BALANCE

PRIMARYSETTLING

SECONDARYSETTLING

AERATION

ANAEROBICDIGESTER

OTHEREQUIPMENT BIOGAS

ENEGYRECOVERY

ENERGY DEMAND REDUCTION IS

NECESSARY TO CLOSE THIS GAP

Energy Intensity in Water Reuse

12AM

8AM

2PM

2.5x

Sobhani and Rosso (2011) WEFTEC Proc.

NORMALIZED METRICS DO NOT NECESSARILY REFLECT ACTUAL IMPACT

INCREASING WATER QUALITYINCREASING WATER QUALITY

INFORMATION IS POWERRosso et al (2012) Wat. Practice Technol.

eFPTOT eFPii1

n

n j pj j t jj1

m

i1

n

#units power efficiency time in operation

Sobhani et al (2012) Desalination 291 106-116

Water-Energy-Efficiency• 99% water recovery• Zero Liquid Discharge

(from waste to commodity)• Current 40MGD pilot in

construction• Minimum energy usage

BIG CHALLENGES

• IS ENERGY INTENSITY A GOOD INDICATOR?• WHAT ABOUT POWER DENSITY?• SHOULD THE OVERALL ENERGY COST BE THE METRIC?• THE ADVENT OF RELIABLE AMMONIA SENSORS• REAL-TIME AERATION EFFICIENCY MONITORING

PROCESS ANALYSIS AND AUDITS

The cost of inefficient primariesBiogas production with and without primary settling Gori et al (2013) Wat. Sci. Technol.

REMEMBER:CHALLENGES

IN FLOW METERING

GAS SENSORS ARE MORE THAN HOT AIR

CPU

OTR = (kLa∙V) [Csat-(DOexc+DOneeded)] = kgO2/d = $$$/d

Off-gas

Real-Time Off-Gas Analysis

- These analyzers provide measurements necessary for aeration efficiency improvement and aeration energy savings - Gas analyzers can provide real-time measurement of aeration energy- No fouling issues

Leu et al (2009) Wat. Environ. Res.

POWERDENSITY (W/m3)

ENERGY INTENSITY (Wh/m3)

Activated Sludge Process:Diurnal Dynamics

VAR

IATI

ON

REL

ATIV

E TO

AVE

RA

GE

IMPORTANCE OF PROCESS DYNAMICS: POWER vs. ENERGYPOWER DEMAND CHARGES: kW and kVAR

TREATMENT vs. CARBON FOOTPRINT

Neethling et al (2011) Proc. WEFTEC

INCREASING WATER QUALITY

INC

REA

SIN

G C

-FO

OTP

RIN

T

!: THE LEVEL OF TREATMENTTAILORED TO THE END-USE

MUST ALWAYS BE MAINTAINED

THE ELEPHANT IN THE COUNTRY

• The majority of ww is treated by few plants• Most of them use pure oxygen (HPOAS)• Near the end of their useful life• Effluent not suitable for reclamation/reuse• What should we do?

The Power of Fouling

PROCESSDYNAMICS

EQUIPMENTEFFICIENCY

POWERBILL

MANAGEMENTSOLUTIONS

PROCESSENERGY

OPERATINGCONDITIONS

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Thanks to:WE&RF

CECMANY UTILITIES

Daniel NolascoBen Leu

Lory LarsonMike Stenstrom

Josh SmeraldiLuman Jiang

Reza SobhaniManel GarridoRiccardo Gori

Francesca Giaccherini

DIEGO ROSSObidui@uci.eduepl.eng.uci.eduwex.eng.uci.edu