Automatization of water quality monitoring in RASsmoltproduksjon.no/Bilder/TidlKonf 2014/Kolarevic.pdf · – Sensitive systems (down to ppb level) are available of colorimetric type,

Automatization of water quality monitoring in RAS

Jelena Kolarevic, Dag Bundgaard, Britt Kristin Megård Reiten, Kristin Skei Nerdal and Bjørn-Steinar Sæther

07/11/2014 3rd RAS conference, Sunndalsøra 2

AQUAlity project

The aim of the EU FP7 project AQUAlity is to lower costs for European fish farmers by developing a multi-sensor platform for continuous monitoring of water quality in RAS that will also contain built-in knowledge of best practice conditions for the farmed species in close-containment systems.

SEVENTH FRAMEWORK PROGRAMME FP7-SME-2008-2

Multi-sensor platform specifications


Parameter

Unit

Recommended

values

Max. (range of) values measured in

commercial RAS

Aimed

Accuracy

Range of values measured by AQUAlity

platform

Comments

Temperature oC depends on fish

species 0 - 32 ± 0.5 0 - 32

O2 % 85-100 % 0 - 250 % ±2% 0 - 250

CO2 mg l-1

10 -15 40 ± 0.5 0 - 50

Nitrite nitrogen (NO2-N) mg l-1

≤ 0.1 15 ± 0.01 0.01-100

Total ammonia nitrogen (TAN)

mg l-1

2 (at pH=6.8, 12

oC)

10 ± 0.1 0.1 - 100

Unionised ammonia nitrogen (NH3-N)

µg l-1

3 (at pH=6.8, 12

oC)

depends on the pH and temperature

± 0.1 0.1 - 5000 suggested range of measurable values covers pH range between 6-9 and temperature range between 0 -

32oC up to 10 mg l

-1 TAN

Ionised ammonia nitrogen (NH4

+-N)

mg l-1

3 (at pH=6.8, 12

oC)

depends on the pH and temperature

± 0.1 0.1 - 100 suggested range of measurable values covers pH range between 6-9 and temperature range between 0 -

32oC up to 10 mg l

-1 TAN

pH 6 - 8 6 - 9 ± 0.1 0 - 14

How accurate are continuous measurements of

TAN and NO2-N in aquaculture?

Ammonia and nitrite sensor requirements

Accurate measurements of TAN and NO2-N in aquaculture systems

Multiple measurements during one hour during 24h

Easy maintenance maximum once a week

Minimal use of chemicals

Small in size (“size of a shoe box”)


Survey of the commercial sensors used in aquaculture (Philips)

Adequate commercial probes available for DO, CO2 , pH, and temperature

For ammonium and nitrite:

– Current compact, low service sensors (mainly of ISE type) are not

sensitive and accurate enough for AQUAlity.

– Sensitive systems (down to ppb level) are available of colorimetric type,

however those are bulky/complex and require consumption of sampled water

and a continuous adding of reagents.

– None of the commercial sensors fully cover the targeted AQUAlity specifications


AQUAlity platform components


by Chris Abbott, ISRI and Kees Bink, Philips

AQUAlity platform testing

• Testing of the MACA functional model @Nofima

• Testing of the platform performance @ Nofima:

- Sensor accuracy and maintenance

- AQUAlity software testing

• Field trials @ Truchas De La Alarria (Spain) and

Fischzucht Abtshagen GMBH & COFISCH (Germany)


• Freshwater RAS

• Production of smolt

• Sensors in the pump sump

• Regular water sampling

• Data logging

Nitrite nitrogen


Std (mg/L) 0.00 0.01 0.05 0.10 0.50 1.00 2.50 5.00 10.00

y = 1.963x + 0.0011 R² = 0.9927

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 1 2 3 4 5 6 7 8 9 10

Ab

sorb

ance

NO2-N concentration (mg/L)

MinAbsorbanceMaxConc.0-1 mg/L

• Calibration of MACA using standard solution of the

known concentration

• Intense colour development already @ 2.5 mg/L

• Manual calibration for 5 and 10 mg/L

Incubation time: 3 minutes Absorbance peek: 540 nm Temperature: 25oC

0

0.2

0.4

0.6

0.8

1

1.2

450 550 650 750

0.5 mg/L

Absorbance_2

Absorbance_1

low

upper


Continuous NO2-N measurements

0.00

0.05

0.10

0.15

0.20

0.25

00:00 02:24 04:48 07:12 09:36 12:00 14:24 16:48

NO

2-N

co

nce

ntr

atio

n (

mg

L-1)

Time since the start of analysis (hh:mm)

• Using RAS water for 16 hours

• Measurements every 19 minutes

Min. 0.11 mg L-1

Max. 0.21 mg L-1

Average 0.15 mg L -1

NO2-N (Mean±SD)

Autoanalyser 0.0398 ± 0.001

MACA 0.0480 ± 0.002


Std (mg/L) 0.0 0.1 0.5 1.0 2.5 5.0 10.0

TAN • Manual MACA calibration for TAN • Oxyguard is continuing the work with TAN measurements

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 2 4 6 8 10

Ab

sorb

ance

TAN concentration (mg L-1)

Mean absorbance

Max absorbance

Min absorbance


Sensor maintenance: pH

• Salinity and pH (temperature) probes important for calculation of ammonia

• 3 different maintenance methods used: calibration, agitation and cleaning with H20

• Formation of the biofilm on the pH probe surface - between 0.1 and 0.5 lower pH

measurements ( >50% lower NH3-N than present )

• Installation of the cleaner head

O2 CO2

TGP

pH

Sal.

O2

pH


O2 CO2

TGP

pH

Sal.

• Biofilm formation on the O2 probe

• Higher saturation levels after cleaning up to 33%!

• Proper maintenance necessary

• Installation of the cleaning head (max ΔO2=1.8%)

Sensor maintenance: O2


O2 CO2

TGP

pH

Sal.

• CO2 probe more resilient to biofilm formation than O2 probe

• Max ΔCO2 = 2.8 mg L-1

Sensor maintenance: CO2


7

7.1

7.2

7.3

7.4

7.5

7.6

7.7

7.8

7.9

pH pH WTW

pH Aquality

pH online Nofima

Calibration of AQUAlity pH probe



pH sensor accuracy • 3 different probes used

• No maintenance between 12.05-19.05

• Similar measurements as other on-line probe

• Proper maintenance is crucial for accurate measurements!

0.3 0.15

0.11

Regular maintenance


0

1

2

3

4

5

6

7

8

9

10

CO

2 c

on

cen

trat

ion

(m

g L-1

)

CO2 Franatech

CO2 AQUALity

Carbon dioxide sensor accuracy

4.4 mg/L

No maintenance AQUAlity probe

• Tested against Franatech CO2 probe that was cleaned every day before the measurements were done • Sensitive to the formation of the biofilm • Regular maintenance necessary

Regular maintenance both probes


The AQUAlity software tools • Components:

Desktop stand-alone farm control system

- local database of water quality data

- desktop application for real time data monitoring & trend analysis

AQUAlity webservices

Web-based expert’s analysis application


The AQUAlity software testing

• Production & system information input

• Data logging every 5 minutes to a local database

• Data export to excel or to expert database

• Real-time measurements updated every 10 sec.

• Farm benchmarking

• Experts recommendations


The way further…….

• Development of the MACA to the market (Oxyguard)

• Use of the AQUAlity software by the fish farmers association

• Development of the expert database

• Large database for farm benchmarking

• Education on proper use of the on-line probes for water quality


The research leading to these results has received funding from the European Union’s Seventh Framework Programme managed by REA Research Executive Agency (http://ec.europa.eu/research/rea) (FP7/2007-2013) under grant agreement number [286995] in a research for the benefits of SME associations, project AQUAlity: “Multi-sensor automated water quality monitoring and control system for continuous use in recirculation aquaculture systems”.

Thank you for your attention !

[email protected]

mailto:[email protected]

Documents

Automatization of water quality monitoring in RASsmoltproduksjon.no/Bilder/TidlKonf 2014/Kolarevic.pdf · – Sensitive systems (down to ppb level) are available of colorimetric type,