Growth of Lettuce in Hydroponics Fed with Aerobic- and Anaerobic–Aerobic-Treated Domestic Wastewater

Jörn Germer (), Christian Brandt, Frank Rasche, Thomas Dockhorn and Alexa Bliedung
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Jörn Germer: Hans-Ruthenberg-Institute for Tropical Agricultural Sciences, Universität Hohenheim, Garbenstrasse 13, 70593 Stuttgart, Germany
Christian Brandt: Hans-Ruthenberg-Institute for Tropical Agricultural Sciences, Universität Hohenheim, Garbenstrasse 13, 70593 Stuttgart, Germany
Frank Rasche: Hans-Ruthenberg-Institute for Tropical Agricultural Sciences, Universität Hohenheim, Garbenstrasse 13, 70593 Stuttgart, Germany
Thomas Dockhorn: Institute of Sanitary and Environmental Engineering, Technische Universität Braunschweig, Universitätsplatz 2, 38106 Braunschweig, Germany
Alexa Bliedung: Wasserwirtschaftsamt Ingolstadt, Auf d. Schanz 26, 85049 Ingolstadt, Germany

Agriculture, 2023, vol. 13, issue 8, 1-21

Abstract: Reusing water and nutrients from municipal wastewater can conserve resources and reduce wastewater treatment costs. In this study, the suitability of different qualities of treated wastewater for plant production in a hydroponic flow-through system was investigated. Lettuce ( Lactuca sativa L.) was grown in hydroponic lines fed with treated wastewater, i.e., conventional effluent from aerobic wastewater treatment by the activated sludge process (CE), ozonised CE (CEO), anaerobically pre-treated and nitrified wastewater (AN) and biological activated carbon filtered AN (ANC) in comparison with a modified Hoagland nutrient solution. In CEO, AN and ANC, the lettuce reached a similar weight and elemental composition as that in HS. The low N and P concentrations in CE and CEO were quickly depleted, resulting in limited plant development at the ends of these lines. The lower water content in the CE shoots was probably related to hypoxia that occurred at higher temperatures. In the CEO line, this condition did not arise due to the constant decay of O 3 . At lower temperatures, the CEO shoot dry weight was 90% higher than that in CE. This was possibly an effect of residual ozone and/or oxygen supersaturation. AN produced the highest yield, while carbon filtration lowered the content of cations in ANC, inducing deficiency of Fe > Mn > Cu > Zn > K. Coupling wastewater treatment with hydroponics allows for efficient nutrient recovery, and thus could reduce the energy and reactor volume needed for N and P elimination.

Keywords: activated sludge treatment; biological activated carbon filtration; micronutrient deficiency; nitrogen depletion; ozonation (search for similar items in EconPapers)
JEL-codes: Q1 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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