www.jacobs.com | worldwide

Nitrogen Shortcut, Carbon Redirection and

Enhanced Oxygen Transfer: Elements of a Roadmap

to Sustainable Energy Independence Julian Sandino, PE, PhD, BCEE, WEF & IWA Fellow

MWEA Sustainable Energy & Process Joint Seminar

Battle Creek, MI

October 17, 2018

What is driving projects?

Addressing today’s issues…

– Aging infrastructure

– Service area changes

– Water stress

– Increased regulations

– Mitigating community and

environmental impacts

– Improve O&M efficiencies

While positioning for the

future...

Energy optimization: essential for

sustainable wastewater management

• Energy consumption has

significant environmental &

social impacts

• Energy is 2nd to labour in cost

of “used” water management

• Energy requirements limit

recovery of some resources

• Energy optimization =

f(reducing consumption;

increasing recovery)

Sustainable Energy

Management

A multi-pronged approach

to energy management

– Energy Use

Optimization

– Energy Recovery

Balancing carbon in the wastewater holds

the key to energy optimization

• Effective primary treatment reduces carbon load

to subsequent processes reducing energy

consumption

• Redirected carbon offers potential of significant

energy recovery

• Conventional BNR relies on carbon for nitrogen

and phosphorus removal.

• Mainstream deammonification: alternative to

current energy intensive carbon driven

processes

Deammonification: requires less energy

and allows for carbon redirection

1 mol Ammonia

(NH3/ NH4 +)

1 mol Nitrite(NO2

- )

1 mol Nitrate(NO3

- )

38% O2

1 mol Nitrite(NO2

- )

½ mol Nitrogen Gas(N2 )

25% O2

60% Carbon

NITRIFICATIONAerobic , Autotrophic

40% Carbon

Anammox

bacteria

DENITRIFICATIONAnoxic, Heterotrophic

VandCenter Syd (VCS)

• Established in 1853 as first modern waterworks in

Denmark

• 3rd largest water and wastewater company in

Denmark. Headquartered in Odense.

• Adopted in 2010 goal of achieving energy and CO2

neutrality in 5 years

• Ejby Mølle WWTP: 410,000 PE BNR facility; energy

self-sufficient in 2014

• Beyond Energy Neutrality Program: Jacobs

developed approach and assisted in the

implementation of multiple projects that by 2016

resulted in 115% electrical power and 160% heat self-

sufficiency. Excess heat is being sold to District

Heating grid, with locations as far as 20 kms away.

• Awards: 2013 Water and Energy Exchange (WEX)

Global Innovation Award (Madrid); International

Water Association’s 2018 Project Innovation Award

Ejby Mølle WWTP

DEMONTM selected for sidestream N removal

Sidestream

deammonification

reactors at the EMWWTP

Operational 2014

Mainstream deammonification was enabled by

adding hydrocyclones to the WAS flow

Dewatering

Centrate

Influent Primary

Clarifiers

WAS

Bioreactor (aerobic/anoxic)

Effluent

DEMON

Reactors

AOB Seed

Anammox

Seed

CEPT

Mainstream

hydrocyclones

Nitrogen shortcut allows further carbon redirection

• Improving primary clarification removal

– Historically 65-70% TSS removal w/o chemicals

– How much more will CEPT remove?

• Optimizing the trickling filter process

– Kept alive for wet weather flow conditions (~ 20% PE)

– Maximize PE feed to meet minimum wetting rates

• Reduces carbon and ammonia to bioreactors (lower O2 demand = lower energy)

• Nitrified effluent fed to bioreactors; sufficient carbon

• Increases biogas production11

Deammonification has contributed to net positive energy

status

12

0

5000000

10000000

15000000

20000000

25000000

2011 2012 2013 2014 2015 2016

En

erg

y,

kW

h

Electric Power Generated Heat Generated Electric Power Consumed Heat Consumed

En

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pti

miz

ati

on

Stu

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on

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ica

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Ele

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Carbon redirection reduces energy consumption from

secondary processes and recovers energy from sludge

• Conventional primary

treatment

• Chemically enhanced primary

treatment

• “A” stage of A/B Process (high

rate biological contact)

“A” Stage Dissolved Air Flotation

• Combines grit and FOG removal, biological contact, primary

treatment, P removal and sludge co-thickening

• Small footprint

Agua Nueva WRF, Pima Co., AZ

Solids Processing is Key to Energy Recovery

Opportunities

Brands Sands,

UK

Minworth, UK

DCWater, DC

Tuas WRP, SGP

Jurong WRP,

SGP

Bonnybrook WWTP,

AB

San Francisco

PUC, CA

Thermal Hydrolysis Process

HaarslevTM HCHS 2 operating facilities

Semi-continuous process

Lower complexity

17-22% TS pre-dewatering

Compact vacuum condenser

- overall smaller footprint

Lower heat requirements

Lower O&M costs

KC-based service center

ExelysTM

2 operating facilities

Continuous process

Lower complexity

18-24% TS pre-dewatering

Smaller systems

Dynamic steam mixer

Lower heat requirements

Lower O&M costs

Class A not proven

Cambi© THP >90% of all operating facilities

Batch process

Higher complexity

17% TS pre-dewatering

Oversized systems

Higher heat requirements

Higher O&M costs

Cooling footprint can be

significant

Modular- easy to install

Summary of Energy/Mass Balances and Costs - EMWWTP

Scenario

Electricit

y Sold

(MWh/d)

Heat

Sold

(MWh/d

)

Total

Energy

Sold

(MWh/d)

Biosolids

to

Disposal

(Wet

ton/d)

Simple

Payback

(Years)

Baseline 23.7 16.4 40.1 53 -Full THP 29.1 22.9 52.0 32 9WAS Only THP 29.4 30.7 60.1 38 10

Post-Digestion THP 26.7 15.3 42.0 23 16

Intermediate THP 23.4 4.3 27.7 30 28

Full THP +

Incineration29.1 37.6 66.7 6 55

Co-digestion maximizes use of existing assets –

potential for net positive energy condition!

• Fats, oil & grease (FOG)

• Food industry wastes

• Organic fraction of municipal

solid waste (OFMSW)

• Animal Manures

Energy recovery/generation: The key to neutrality and

beyond

19

F. Wayne Hill Water

Resources Center

Solids processing Point Loma WWTP -1.35 MW

San Diego, CA (90 ft)

Hydropower

Effluent Heat Recovery Wind Turbines

ACUA WWTP, NJ - 7.5 MW

Solar Panels

Rogers Rd. WWTP, AZ – 1.1 MW

MABR = Membrane Aerated Biofilm Reactor

• Bundles of hollow fibre gas permeable

membranes through which air (or oxygen) is

passed

• “Bubbleless” aeration – biomass directly

grows on membrane surface

• Technology that can be easily installed in

existing bioreactors to:

– Improve oxygen transfer efficiency and

reduce energy(3-4 times diffused aeration)

– Increase secondary treatment capacity

– Improve biological treatment performance

(e.g. ammonia removal)

Desktop evaluation suggests significant

benefits of a MABR retrofit at Ejby Mølle

• 40% reduction in energy consumption in BNR process

• 45% increase in achievable peak flow secondary clarifier

capacity

• 20% reduction in annual nitrogen mass discharged

• 5% increase in biogas production due to lower SRT

operation

Demonstration testing with full-scale units aimed at answering

several key questions for full scale implementation

• Biofilm management

– Is stuff going to get stuck?

– Is screening material an issue?

– What impact does mixing intensity and

scour have on performance?

• Taking advantage of the unique biofilm

– Shortcut nitrogen removal?

– Impacts on N2O emissions

• Response to dynamic flows and loads

In and out of basin configuration allows testing

MABR for different goals

Effluent

RAS

Primary Effluent

MABR module

Zone 1 RAS Fermentation

Zone 2

Zone 3

Zone 4

Effluent

RAS

Primary Effluent

Zone 1 RAS Fermentation

Zone 2

Zone 3

MABR Zone

In-basin MABR testing

• One of each manufacturer

in Zone 4

• Testing goals: biomass

accumulation, material

clogging (if any), O2

transfer rate

• Removal every 4 to 6

months for inspection

Parallel MABR testing out of basins

• Specific rate testing

• Diurnal variation

impacts

• Flow fed at ~1% of total

influent flow

• N2O emissions

• Removal every 4 to 6

months for inspection

MABR Demonstration Study – Collaborative

effort from key partners

Some summary thoughts …

• Energy is only 2nd to labor in the cost of treatment/ reclamation of water

• After water, energy is the most cost-effective and environmentally beneficial

resource to be recovered in a C-constraint world

• Energy self-sufficiency (even net positive status) is possible with typical

“used” water

• Balancing nutrient removal, carbon management, energy conservation, and

energy production is key

• Carbon management through redirection is key in energy optimization

• Recent developments such as mainstream deammonification and MABRs

are now increasingly being considered to help utilities achieve external

energy independence

www.jacobs.com | worldwide

Nitrogen Shortcut, Carbon Redirection and

Enhanced Oxygen Transfer: Elements of a Roadmap

to Sustainable Energy Independence

Julian Sandino, PE, PhD, BCEE, WEF & IWA Fellow

MWEA Joint Sustainable Energy & Process Seminar

Battle Creek, MI

October 17, 2018

Q & A