Performance of Pistia stratiotes, Salvinia molesta, and Eichhornia crassipes Aquatic Plants in the Tertiary Treatment of Domestic Wastewater with Varying Retention Times

Hauwa Mohammed Mustafa,Gasim Hayder

doi:10.3390/app10249105

Hauwa Mohammed Mustafa, Gasim Hayder

Open Access

https://doi.org/10.3390/app10249105

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Abstract

Organic matter, nutrients, and chemicals are some of the waste materials found in most domestic wastewaters. The purpose of this research was to evaluate the potentials of Pistia stratiotes, Salvinia molesta, and Eichhornia crassipes aquatic weed plants in the tertiary treatment of secondary domestic wastewater using hydroponic systems. Physicochemical analysis that considered turbidity, phosphate, ammoniacal nitrogen, and nitrate was conducted on the wastewater samples at different retention times of 6, 12, and 24 h for 14 days. The best performance was observed for a 24 h retention treatment system, with up to 91% (P. stratiotes), 94% (S. molesta), and 89.3% (E. crassipes) reduction for turbidity; 81.2% (P. stratiotes), 82.7% (S. molesta), and 88.5% (E. crassipes) for phosphate reduction; 88.66% (P. stratiotes), 90.47% (S. molesta), and 89.11% (E. crassipes) for ammoniacal nitrogen reduction; 83.6% (P. stratiotes), 92.1% (S. molesta) and 93% (E. crassipes) for nitrate reduction. Hence, the application of hydroponic systems in cultivation of the macrophytes proved to be effective in the phytoremediation process by removing the residual nutrients present in the treated secondary domestic wastewater. Additionally, this method can be used for the cultivation of plant-based biomass and other non-edible useful crops using the free nutrients content of the wastewater before its discharge into the natural environment.

Highlights

The utilization and quest for clean renewable energy have become critical due to the growing interest in clean energy and water sources [1,2]
It was observed that the reduction of the turbidity level for the influent wastewater samples by the test plants was obvious from the beginning to the end of the sampling duration
The reduction efficiency ranges for the P. stratiotes, S. molesta, and E. crassipes wastewater treatment systems were found to be 48–72.7%, 10.19–58.3%, and 28.3–58.88%, respectively

Summary

Introduction

The utilization and quest for clean renewable energy have become critical due to the growing interest in clean energy and water sources [1,2]. Environmental problems can be caused by organic and inorganic compounds found in wastewater [3]. Conventional wastewater treatment methods, which consist of several treatment processes, are not always effective toward the complete removal of water contaminants. A small quantity of these contaminants, such as ammonia, nitrate, and phosphorous, are discharged into river bodies, which can lead to the pollution of groundwater. This can affect human health, disrupt the aquatic ecosystem, kill aquatic animals, Appl.

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