Sulfide control in sewers by intermittently dosing acidified nitrite: from scientific

discovery to application

Zhiguo Yuan

Co-authors

• Guangming Jiang - Advanced Water Management

Centre, The University of Queensland, Australia

• Tony Keating - UniQuest Pty Limited, The University of

Queensland, Australia

• Shaun Corrie - CWE Corrie Water and Environment,

Australia

• Lam Nguyen - US Peroxide, USA

• Kelly O’Halloran - Gold Coast City Council, Australia

2

Water Corp, WA

SA Water

Veolia Water Aus

W Q R A

Barwon Water Melbourne Water

South East Water

Sydney Water

CH2M Hill

Hunter Water

Gold Coast Water

All Australia’s largest water utilities US: DC Water, WERF Europe: Aquafin

Uni QLD

Yarra Valley Water

Actew

The SCORe Project Qld Urban Utilities

Curtin Uni Tech

Background

• Corrosion and odour are major issues for sewer management

• Chemical dosing is a commonly used mitigation strategy

– MHL, iron salts, nitrate and oxygen

– 24/7

• Intermittent dosing is desirable

– pH shock

– Effective, low costs, environmentally benign

4

5

Free nitrous acid (FNA)

HNO2 «NO2

- +H +

pKa=3.398 @ 25oC

100 mgNO2—N/L 0.26 mg HNO2-N/L

@ pH 6.0

0.35 mgNO2—N/L 0.001 mg HNO2-N/L

@ pH 6.0

FNA(mgHNO2-N/L)

0.000 0.005 0.010 0.015 0.020 0.025 0.030

% N

H4

+-N

co

nsu

mp

tio

n

0

20

40

60

80

100

pH=7.0

pH=7.5

pH=8.0

pH=6.5

100%*e- 451.2*x

R2=0.9409

FNA at ppb levels is inhibitory to a broad range of microorganisms

1.7 ppb (equivalent 0.6 mgNO2-N @ pH 6) Ye et al. (2010)

7

What if we increase the FNA concentration by 100 times (to sub-ppm levels)? Can we kill cells in sewer biofilms?

Biocidal effect revealed in sewer reactors

8

Jiang et al., (2011a,b)

7 days

Synergistic effects of FNA and H2O2

9

Jiang et al., (2013)

Cloevis

A proprietary mix of chemicals

Kills 99% of bacteria in laboratory trials Proven in field trials to stop sulfide production

Intermittent, once-a-week dosing

Cloevis: Field trial in Gold Coast, Australia

Cloevis: Field trial in Gold Coast, Australia - Dosing, control, and monitoring

Chemicals & dosing rigs

Mix pump

pH probe

etc.

Computer

D 150 mm

S::CAN unit

1080 m

Odalog

(H2S gas)

Cloevis: Field trial in Gold Coast, Australia

Jiang et al., (2013)

Methane control

14

Jiang et al., (2010)

Economic Analysis

Environmental effects

Improved wastewater treatment processes

Biodegradable Little change to existing infrastructure and progressive roll-out

LOW RISK

16

On-going work

• Commercial trials in Australia and in the US

• Other applications (e.g. sludge treatment)

• Mechanism studies

Acknowledgements • All FNA team members – past and present

– BNR: Vel Vadivelu, Yan Zhou, Maite Pijuan, Liu Ye

– Sewer: Janani Mohanakrishnan, Oriol Gutierrez, Guangming Jiang

– Sludge: Qilin Wang, Liu Ye, Maite Pijuan

– Membrane: Marc Pidou, Pengzhe Sui, Ludwika Nieradzik

– Microbiology: Frances Slater, Ahmad Rosli, Phil Bond

– Commercialisation: Tony Keating, Howard Leemon, Shaun Corrie

• ARC and utility partners for funding

• USP as a commercial partner

• GCCC for assisting with field testing