Effects of aerated and non-aerated biofilters on effluent water treatment from a small-scale recirculating aquaculture system for Nile tilapia (Oreochromis niloticus L.) Cover

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Effects of aerated and non-aerated biofilters on effluent water treatment from a small-scale recirculating aquaculture system for Nile tilapia (Oreochromis niloticus L.)

Die Bodenkultur: Journal of Land Management, Food and Environment

Volume 70 (2019): Issue 4 (December 2019)

By: Zipporah Gichana, David Liti, Silke-Silvia Drexler, Werner Zollitsch, Paul Meulenbroek, Joseph Wakibia, Erick Ogello, Peter Akoll and Herwig Waidbacher

Open Access

|Apr 2020

Figures & Tables

An illustration of the recirculating aquaculture systems with the aerated and non-aerated biofilters. Arrows indicate the direction of water flow.Abbildung 1. Darstellung der geschlossenen Kreislaufanlage mit den aeroben und anaeroben Biofiltern. Die Pfeile stellen die Fließrichtung des Wassers dar.

Ammonia (NH3-N), nitrates (NO3-N), nitrites (NO2-N) and P (phosphorus) concentrations in the aerated and non-aerated biofilters. Error bars show standard deviations (n = 3).Abbildung 2. Konzentrationen von Ammoniak (NH3-N), Nitrat (NO3-N), Nitrit (NO2-N) und Phosphor (P) in den aeroben und anaeroben Biofiltern. Die Fehlerbalken stellen die Standardabweichungen dar (n = 3).

Boxplot showing nutrient removal efficiencies in aerated and non-aerated biofilters. Median values are shown in each box, vertical bars correspond to maximum and minimum values. Different letters (a, b) above boxplots indicate significant differences between the two types of biofilters (Student t-test) (p < 0.05).Abbildung 3. Boxplotdarstellung der Nährstoffreduktion in den aeroben und anaeroben Biofiltern. Unterschiedliche Buchstaben bei den jeweiligen Box-plots zeigen signifikante Unterschiede zwischen den beiden Filtertypen (Student t-test) (p < 0,05).

Water quality parameters in the fish tanks (Mean ± standard deviation)Tabelle 2_ Wasserparameter in den Fischtanks (Mittelwerte ± Standardabweichung)

Parameters	Units	RAS_1	RAS_2
Temperature	[°C]	26.25 ± 2.72^a	26. 23 ± 2.67^a
pH		7.71 ± 0.19^a	7.72 ± 0.16^a
Dissolved oxygen	[mg L⁻¹]	2.37 ± 0.76^a	2.54 ± 0.79^a
Alkalinity	[mg L⁻¹]	226. 28 ± 36.70^a	223. 68 ± 38.48^a
Ammonia	[mg NH³-N L⁻¹]	2.43 ± 0.87^a	2.58 ± 0.76^a
Nitrate	[mg NO³-N L⁻¹]	2.92 ± 1.63^a	2.76 ± 1.54^a
Nitrite	[mg NO²-N L⁻¹]	0.26 ± 0.18^a	0.24 ± 0.08^a
Phosphorus	[mg L⁻¹]	1.48 ± 1.08^a	1.57 ± 1.06^a

Water quality parameters in the sump (fish tanks outlet/biofilter inlet) and aerated and non-aerated biofilter outlets_ Mean values (± standard deviations) within a row with different superscripts are significantly different (a > b > c, p < 0_05)_Tabelle 1_ Wasserparameter im Sammelbehälter (Übergangsbereich vom Fischtanks zum Biofilter) sowie jeweils am Ende der aeroben und anaeroben Biofilterkette_ Mittelwerte (± Standardabweichung) innerhalb einer Zeile mit unterschiedlichen Hochzahlen unterscheiden sich statistisch signifikant (a > b > c, p < 0,05)_

Parameters	Units	Sump	Aerated biofilters	Non-aerated biofilters
Temperature	[°C]	25.18 ± 1.48^a	25.37 ± 1.70^a	25.50 ± 1.92^a
pH		7.81 ± 0.11^b	7.78 ± 0.09^b	7.70 ± 0.09^a
Dissolved oxygen	[mg L⁻¹]	2.89 ± 0.41^c	2.11 ± 0.77^b	1.45 ± 0.39^a
Alkalinity	[mg L⁻¹]	242.69 ± 32.83^a	216.79 ± 46.93^a	234.23 ± 56.13^a
Ammonia	[mg NH₃-N L⁻¹]	3.41 ± 0.39^b	1.96 ± 0.60^a	1.95 ± 0.65^a
Nitrates	[mg NO₃-N L⁻¹]	2.49 ± 0.60^b	3.16 ± 0.74^c	1.47 ± 0.89^a
Nitrites	[mg NO₂-N L⁻¹]	0.36 ± 0.16^a	0.55 ± 0.15^a	0.18 ± 0.07^a
Phosphorus	[mg L⁻¹]	2.14 ± 1.15^b	1.71 ± 1.25^ab	1.22 ± 0.78^a

Growth performance of O_ niloticus in the recirculation aquaculture systems with aerated and non-aerated treatments_ All values are means ± standard deviations obtained from three replicates_Tabelle 3_ Wachstumsentwicklung von O_ niloticus in der Kreislaufanlage mit aeroben und anaeroben Filtern_ Alle Werte stellen Mittelwerte ± Standardabweichungen aus den drei Wiederholungen dar_

Parameters	Units	Treatments
Parameters	Units	Aerated biofilter	Non-aerated biofilter
Initial Mean Weight	[g]	54.5 ± 4.7^a	56.2 ± 2.7^a
Final Mean Weight	[g]	132.0 ± 18.0^a	129.8 ± 12.8^a
Weight gain	[g]	77.5 ± 17.2^a	73.6 ± 12.5^a
Specific growth rate	[% day⁻¹]	0.42 ± 0.07^a	0.38 ± 0.07^a
Final density	[kg m⁻³]	12.76 ± 2.45^a	12.84 ± 1.36^a
Feed conversion ratio		2.67 ± 0.62^a	3.04 ± 0.65^a
Survival rate	[%]	95.6 ± 4.44^a	93.3 ± 4.24^a

DOI: https://doi.org/10.2478/boku-2019-0019 | Journal eISSN: 2719-5430 | Journal ISSN: 0006-5471

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Language: English

Page range: 209 - 219

Submitted on: Apr 3, 2019

Accepted on: Sep 17, 2019

Published on: Apr 21, 2020

Published by: Universität für Bodenkultur Wien

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

denitrification,

removal efficiency

Related subjects:

Life sciences, other

© 2020 Zipporah Gichana, David Liti, Silke-Silvia Drexler, Werner Zollitsch, Paul Meulenbroek, Joseph Wakibia, Erick Ogello, Peter Akoll, Herwig Waidbacher, published by Universität für Bodenkultur Wien
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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