wastewater reuse for urban irrigation · according to carrow et al. 2002. turfgrass soil fertility...

16th International EWA Symposium “Sustainable Wastewater Management – New solutions for new problems”

Munich, Germany, 8-9 May 2012

a NSF Engineering Research Center ReNUWIt,

Colorado School of Mines

Department of Civil and

Environmental Engineering,

Golden, CO, USA

b Aqua-Aerobic Systems Inc.,

Rockford, IL, USA

Jan Benecke

Cand. Ing. (TU Berlin)

[email protected]

WASTEWATER REUSE FOR URBAN IRRIGATION

Tailored Nitrogen Removal in a Full-Scale

Decentralized Hybrid SBR-MBR

Jan Benecke, J. Henkel, D. Vuono,

T. Y. Cath, J. E. Drewes a

L. W. Johnson, T. Reid b



Introduction

Arising Water Management Challenges

Historic Water Management:

import of freshwater to cities

single usage

transportation & treatment

discharge

Arising Challenges

population growth

urbanization

climate change

local supply shortages

require

local water reuse



Introduction

Wastewater Reuse for Urban Irrigation

Local Reuse of Water + Nitrogen

saves freshwater

sources

replaces inorganic

N-fertilizer

Control of N-Removal

prevent nitrification

control SRT

limit denitrification

control O2



Season H2O N c(N)

[mm/d] [mg/(d·m²)] [mg/L]

Spring 8 40 – 80 5 – 10

Summer 12 80 – 160 7 – 14

Winter 0 0 *

* discharge requirements

Introduction

Tailored Nitrogen Removal

according to Carrow et al. 2002. Turfgrass Soil Fertility & Chemical Problems: Assessment and Management.

Seasonal Variation of

plant growth

water requirements

nitrogen requirements

Jan Dec Jul

Growth Rate + N Demand

Tailored N Removal

seasonal control of c(N)

prevent ion of over-

or under fertilization



SBR-MBR

Site Location – Golden, CO, USA

Colorado School of Mines

Student Housing

SBR-MBR

Field

Laboratory

Green

House

Parking Water Reuse

Test Areas

Process Unit

Treatment Areas

Raised Plots

Photo

Bioreactors

Sustainable Water

System Site

Google Earth



SBR-MBR

Process Flow Diagram



Flow (Q)

=

≈

24 d-1 x 1.14 m³

27.3 m³/d

140 PE

Volume (V) 23.9 m³

VER (VF/VT) 10 %

SRT ≈ 35 d

MLSS ≈ 6 g/L

Treatment Time

=

1 h Fill

1 h Draw

2 h Total

Membrane Module PURON® (KMS)

Surface Area (A) 2 x 30.6 m²

Net Flux (J) 19 L/(m²·h)

SBR-MBR

Select Process Parameters

www.filtsep.com



Results

Research Objectives

Modify system operation to tailor effluent nitrate

concentrations

Investigate reversibility of operational modifications

Assess energy demand for tailored nitrogen removal

Investigate impacts on system robustness

(membrane performance, maintenance)



Results

SBR-MBR Nutrient Removal Performance

Influent Effluent Removal [%]

SUMMER

BREAK

2011

COD [mg COD/L] 354 12 96

T-N [mg N/L] 38.5 4.4 88

T-P [mg P/L] 4.7 2.8 40

3 month operation (n = 8)

FALL

TERM

2011

COD [mg COD/L] 471 18 96

T-N [mg N/L] 57.6 4.2 93

T-P [mg P/L] 6.8 2.3 (< 0.2) 66 (98)

1.5 month operation (n = 8)



Results

Tailored N Removal - SBR Treatment Cycle

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60 80 100 120

Nit

roge

n [

mg

N/L

]

Time [min] NO3-N NH3-N

ANOXIC OXIC ANOXIC OXIC ANOXIC

INFLUENT



Results

Tailored N Removal – Aeration Setup

0

10

20

30

25 32 39 46 53 60

[NO

3-N

] ein

mg/

L

Time [d]

NO3 (lab)[NO3-N]e (lab)

3F 6F FDFD



Results

Tailored N Removal – Aeration Setup (2)

0

10

20

30

58 65 72 79 86 93

[NO

3-N

] ein

mg/

L

Time [d]

NO3 (lab)[NO3-N]e (lab)

9 6 FDFD FD



Conclusion

Results

Nitrogen-removal can be tailored as a function of

season or irrigation needs

Tailored effluent nitrate concentrations are achieved

quickly

Operational modifications are reversible

(full denitrification recovered after a few days)

Energy consumption to retain NO3-N in effluent is

competitive to fertilizer production



Conclusion

Further Studies

Characterize bacterial/archaeal communities during

tailored N removal (reversibility)

Long term experiments (robustness) + urban landscape

irrigation

Assessment of health risks

Detailed analysis of environmental and economical

impacts (LCA)



Acknowledgements

Special thanks to:

Aqua-Aerobic Systems, Inc. for their generous support

Hach Company for providing an online nitrate probe

wastewater reuse for urban irrigation · according to carrow et al. 2002. turfgrass soil fertility...

Documents