Research Program D: Biological Management of

Nitrogenous Chemicals in Small Systems: Ammonia, Nitrite, Nitrate, and N-Disinfection By-Products (N-DBPs)

Mary Jo Kirisits, Jerry Speitel, Kerry Kinney, Michal Ziv-El, Emily Palmer, Ethan Howley, Abel Ingle, Ryan Howell

University of Texas at Austin

Dave Reckhow, Chul Park, Soon-Mi Kim University of Massachusetts (Amherst)

Jess Brown, Carollo Engineers

1

Introduction • Brief Description: Examine biological management of the nitrogenous

contaminant grouping (ammonia, nitrite, nitrate, and N-DBP precursors) • D1: Nitrification • D2: Denitrification • D3: N-DBPs

• Anticipated target utility characteristics: Utilities with source water containing ammonia or nitrate

• Continuum of technology development:

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NO3- NO2

- NO N2O N2

NH4+ NO2

- NO3-

Precursors N-DBPs

D1: Nitrification • Isolate and concentrate natural organic matter (NOM) for use in bench-

scale nitrifying filters

• Examine nitrification at the bench scale for different NOM sources

• Determine if production of soluble microbial products (SMP) can be leveraged to spur removal of trace organic contaminants (TrOC) via heterotrophs

• Examine ammonia and TrOC removal at the pilot scale

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D1: Nitrification

Natural Organic Matter (NOM) Isolation and Concentration

Jonathan Herrboldt

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Introduction Brief Description: Obtain a concentrated NOM solution for use in nitrification (and other) experiments. Process • Step 1: NOM isolation • Step 2: NOM concentration

Materials Setup originally part of EPA-funded work to study treatment of stormwater runoff

Source: Ingenloff, 2011

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5.0-μm and 0.5-μm filters • Reduces fouling of ion exchange

resin and reverse osmosis (RO) membrane

• Filtrate contains dissolved organic carbon (DOC)

Cation Exchange Resin • Reduces fouling of RO membrane • Removes undesirable constituents

(e.g. Ca2+, Mg2+, etc.)

NOM - Isolation Step

Source: Ingenloff, 2011

0.5-μm Filter 5.0-μm Filter Ion Exchange Tank

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NOM – Concentration Step Reverse Osmosis • NOM solution passed through RO

membrane

• Permeate discarded • ~2600-3000 liters concentrated

to ~ 20-100 liters

Source: Ingenloff, 2011

Permeate Flow R.O. Membrane Concentrate Flow

Variable Flow Drive Feed Flow

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Results: Surface Water Analyte Raw (mg/L) Concentrated (mg/L)

DOC ~3.0-4.0* 269.9

Cl- -- 136.5

NO2- -- 0.0

NO3- -- 0.5

PO43- -- 8.4

Ca2+ 36.7 35.0

Mg2+ 21.7 1.7

K+ 3.8 1.5

Na+ 24.9 8.0 *Source: Austin Water Utility, 2015 Quarterly Water Quality Summary.

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Results: Groundwater Analyte Raw (mg/L) Concentrated (mg/L)

DOC -- 25.9

Cl- -- 1.9

NO2- -- 0

NO3- -- 0.1

PO43- -- 1.4

Ca2+ 295.8 25.1

Mg2+ 267.0 72.1

K+ 28.6 58.7

Na+ 44.2 >250

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D1: Nitrification

Removal of ammonia and trace organic contaminants in bench-scale drinking water

nitrifying biofilters

Michal Ziv-El

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Two primary microbial processes in nitrifying biofilters, both require oxygen

Heterotrophs might help nitrifiers but also compete for oxygen, ammonia, and space in the biofilm.

Nitrification: NH4+ (Ammonium) NO2

- (Nitrite) NO3- (Nitrate)

1. Ammonia-Oxidizing Bacteria and Archaea (AOB and AOA)

2. Nitrite-Oxidizing Bacteria (NOB)

Autotrophic, slow growers, non-motile.

Biodegradable organic carbon (BDOC) CO2

3. Heterotrophic Bacteria

Fast growers, produce significant biomass.

+ NH4+ biomass

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Ammonia and trace organic contaminants (TrOC) in drinking water treatment plants

• Nitrification of ammonia in the distribution system has deleterious effects.

• TrOC (pharmaceuticals, personal care products, pesticides) occurrence increasing

• Due to population growth and direct potable reuse

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Removal of TrOC in biofilters

• Sorption • Biodegradation:

• TrOC concentrations 2-3 orders of magnitude less than biodegradable dissolved organic carbon (BDOC).

• Secondary utilization • Co-metabolism

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Study Objectives and Design

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Study Objectives

Assess in bench-scale nitrifying biofilters: (1) Impact of source of natural organic matter

(groundwater versus surface water) on removal of ammonia and TrOCs.

(2) Changes over time to the microbial communities. (3) Robustness of nitrification and TrOC removal to

perturbations. (4) Formation of N-DBPs.

(1) Impact of source of natural organic matter (groundwater versus surface water) on removal of ammonia.

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Biofilter Set-up

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Biofilter Set-up: Run 1

Water Source Surface water Groundwater Ammonia 1.5 mg-N/L TrOC 5 µg/L

10-minute simulated EBCT at full-scale in each biofilter

GAC

(Aqu

aCar

b 82

0)

Sand

(Ott

awa

Sand

) 17

Suite of TrOC spiked to influent (500 ng/L each)

TrOC Use/Type Chemical Class 2-MIB Taste and odor Geosmin Taste and odor Diclofenac Pharmaceutical/NSAID Phenylacetic acid Naproxen Pharmaceutical/NSAID Propionic acid Gemfibrozil Pharmaceutical/anti-convulsant Fibric acid derivative Atenolol Pharmaceutical/cardiovascular Isopropylamino-propanol derivative Estrone Pharmaceutical/hormone Aromatic C18 steroid Caffeine Food product Thiabendazole Pesticide/fungicide Benzimidazole DEET Pesticide Aromatic amide

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Run 1: Impact of natural organic matter source on removal of ammonia

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Water Quality Parameters

Parameter Groundwater- Edwards Aquifer

Surface Water- Lake Austin

pH 7.7 8 Alkalinity [mg/L as CaCO3] 250 170 Dissolved Oxygen [mg/L] 7.5 7.8 Conductivity [μS] 3260 580 Hardness [mg/L as CaCO3] 1840 180 Dissolved Organic Carbon [mg/L] 0.9-2.5 4.5-15 Assimilable Organic Carbon [μg-C/L] 5-200 1000-3000 NH4

+[mg-N/L] 1.5 1.5 (amended) NO2

- [mg-N/L] 0.0 0.0 NO3

- [mg-N/L] 0.1 0.50 PO4

3- [μg-P/L] 1.4 8.4 20

Nitrification with Groundwater Feed

Ammonia removal complete and stable for groundwater with GAC but not with sand.

Disturbance

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Even small increase in AOC affected nitrification, negatively in GAC and potentially positively in sand biofilters.

Impact of AOC Addition on Groundwater Nitrification AOC addition (75 μg-C/L)

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Nitrification with Surface Water Feed

Nitrification in GAC and sand were similarly unstable (clogging and DO limitation), but GAC was more robust after several disturbances.

Disturbance

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Conclusions From Run 1 • High concentrations of AOC in the surface water source will cause

unstable nitrification. Simulate groundwater concentrations in reconstituted organic matter feeds. • Sand biofilters resulted in low (groundwater) or unstable (surface

water) nitrification, Sand is not a good “no sorption” control for TrOC. Use only GAC biofilters.

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Run 2: Updated set-up, sampling plan, and

current status

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Biofilter Set-up: Run 2 Reconstituted organic matter (1 mg/L DOC)

Surface water Groundwater

TrOC presence (5 µg/L)

Yes

Ammonia presence (1 mg-N/L)

Yes No Yes No

10 minute simulated EBCT at full-scale in each biofilter

GAC

(Aqu

aCar

b 82

0)

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Experiment Stages and Sampling Plan

Stages: 1) Inoculation with raw groundwater (2 weeks). 2) Acclimation to reconstituted waters (2 months). 3) Robustness tests (3 months). 4) Assess sorption versus biodegradation (1 week).

Analytical analyses and frequency: Twice/week: NH3 Weekly: NO2

-, NO3-, pH, DO, turbidity, HPC

Monthly: TrOC, DOC, AOC, N-DBPs.

Microbial community analyses (DNA): Monthly: Fingerprint using MiSeq Illumina and abundances using qPCR

a) Bacteria and Archaea 16S rRNA gene. b) Ammonia oxidizer amoA gene.

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Nitrification Run 2 Stage 1:

Raw Groundwater Stage 2:

Reconstituted Waters

First Monthly Sampling

Contamination

Nitrification start-up was rapid and has been mostly stable for the 20 minute simulated EBCT.

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D1: Nitrification

Pilot Testing Jess Brown

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Synergizing with WRF 4559: Simultaneous Removal of Multiple Chemical Contaminants using Biofiltration

• Eric Dickenson (SNWA) is the PI, Jess Brown involved as a Co-PI • Task 1: Literature Review • Task 2: CEC Indicator Compound Assessment • Task 3: Biofiltration Pilot Testing (3 sites)

• Target Contaminants: TOC, NH3, N-DBP precursors, taste & odor, pharmaceuticals and personal care products, Mn

• Evaluate impact of media type, EBCT, contaminant spiking, and upstream treatment

• Task 4: Full-scale Biofiltration Testing • Task 5: Guidance Tool Development

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Pilot Testing at Houston’s East Water Purification Plant

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Raw Water Blending

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Flocculation & Sedimentation

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Ozone Contactors & Filters

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Scope of Work for Project D1

• Leverage 6-mo biofiltration pilot study at Houston (in operation for 3 wk) • Task 1: Microbial Community Analysis • Task 2: Phosphatase Analysis • Task 3: Extracellular Polymeric Substance (EPS) & Biomass Quantification • Task 4: System Shutdown Robustness Tests (Phase 5 of Pilot Testing) • Task 5: Distribution System Simulation • Analytical work will be done at UT-Austin and UMass- Amherst • Data shared freely between WRF and WINSSS Project D teams

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D1: Nitrification

Impact of Soluble Microbial Products on Trace Organic Contaminant Biodegradation

Emily Palmer

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Research question: Do SMP produced by nitrifying bacteria aid in the removal of TrOC by heterotrophic bacteria?

Background – SMP

• Definition: organic compounds produced during substrate metabolism and biomass decay

• Contain carbon and electrons • Humic substances, proteins, and

carbohydrates

• Size: <1 kDa to >100 kDa

• Produced by heterotrophic and autotrophic microorganisms

Ni et al., 2011

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SMP are biodegradable

• Nitrifying bacteria produce SMP

• Heterotrophic microorganisms can survive on SMP produced by nitrifying bacteria

• Therefore, heterotrophs and nitrifiers have a symbiotic relationship

Kindaichi et al., 2004

Microbial community of reactor fed no organic carbon:

50% heterotrophs, 50% nitrifiers

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Hypothesis: SMP aids TrOC biodegradation

• Nitrifier SMP stimulates heterotrophs to utilize more complex carbons • Leads to production of enzymes for complex carbon degradation

• TrOC are complex carbons as well

• Enzymes for SMP biodegradation also might degrade TrOC

• Additionally, SMP supplies heterotrophs with a carbon source

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Experimental Method

Produce nitrifier SMP Shielded

from light

26 °C

Agitated at 125 RPM Air supplied

pH maintained at 7.8

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Experimental Method

Produce nitrifier SMP

[C] = 5.6 mg/L C 41

Experimental Method

Produce nitrifier SMP

Acclimate heterotrophs to simple (acetate) or complex

(SMP) carbon source Spike TrOC

Monitor TrOC degradation

kinetics over time

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Initial Experimental Design

• Four flasks: 1. SMP + heterotrophs 2. Acetate + heterotrophs 3. SMP + heterotrophs (autoclaved after acclimation) 4. SMP + Pseudomonas aeruginosa

• Acclimated to their respective carbon source for 2 weeks • Spiked with geosmin and monitored for 1 week

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Results – Geosmin

0

0.2

0.4

0.6

0.8

1

0 22.25 46.5 73.75 92 119.75 140.75 164.25

c/c 0

Time (hours)

SMP + heterotrophs Acetate + heterotrophs Killed control SMP + P. aeruginosa44

Revised Experimental Matrix

Flask # Carbon Source Inoculum Killed Control

SMP Acetate Heterotrophs P. aeruginosa Nitrifiers Autoclave Azide

Flask 1 X X

Flask 2 X X

Flask 3 X X X

Flask 4 X X X

Flask 5 X X

Flask 6 X X

Flask 7 X X X

Flask 8 X X X

Flask 9 X X X

Flask 10 X X 45

D2: Denitrification Mitigation of Nitrite Accumulation in

Denitrification Biofilters at Low Temperatures

Emily Palmer

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Research question: Does micronutrient addition to denitrification biofilters ameliorate nitrite accumulation at low temperature?

Background • Denitrification (NO3

- NO2- N2) affected by many factors

• Temperature outside of optimum range (25-35°C)

• Nitrite-reducing bacteria are more sensitive to low temperatures than are nitrate-reducing bacteria

• This can lead to nitrite accumulation. • Maximum Contaminant Level: 1 mg/L NO2

--N

• Nitrite reductase is iron- or copper-based

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Current Bench-Scale Set-Up

Synthetic groundwater : 1 mg/L NO3

- -N 4.5 mg/L acetic acid (110% stoichiometric dose)

Nitrogen tank

Two biofilters in series: • 1.59-min EBCT (each) • 0.77 gpm/ft2 loading rate • 3 mL/min flow rate

• 4.32 L/day

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Experiment Status

• One biofilter moved to 25°C room • Temperature lowered (5 °C increments) to achieve nitrite accumulation • Supplement influent with iron • Send samples for N-DBP formation studies to UMass-Amherst

Next Steps

• Denitrification achieved • Optimizing concentration of acetate to decrease backwash frequency

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Outputs and Outreach Completed: • “Removal of ammonia and trace organic compounds in drinking water nitrifying biofilters: temporal variations in organic

compound removal and microbial community structure“, AWWA Biological Drinking Water Treatment Symposium; January 2016.

Scheduled: • “Impact of soluble microbial products on trace organic contaminant removal from drinking water”, TX Water; April 2016. • “Case Study: Ammonia and trace contaminant removal in bench- and pilot-scale biofilters: microbial community

structures, robustness, and nitrogen disinfection byproducts”, ACE, June 2016.

Anticipated:

•White paper for WINSSS website, Fall 2016.

•Manuscripts for submission to a technical journal •Nitrification (bench-scale) Fall 2016 •Nitrification (pilot-scale) Fall 2016 •N-DBPS, Spring 2017 •Denitrification, Summer 2016

•WINSSS Webinar –Spring 2017 50

Discussion

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