Egyptian Journal of Aquatic Biology & Fisheries Zoology Department, Faculty of Science, Ain Shams University, Cairo, Egypt. ISSN 1110 – 6131 Vol. 23(2): 379 - 396 (2019) www.ejabf.journals.ekb.eg Environmental Remediation of Tilapia Aquaculture Wastewater Using Ceratophyllum demersum and Lemna minor. Mokhtar Beheary 1 , Basma M. Sheta 2 * Menna Hussein 2 , Mona Nawareg 2 , Fatma A. El-Matary 3 and Ayman Hyder 2 1- Environmental Science Department, Faculty of Sciences, Port Said University. 2- Zoology Department, Faculty of Science, Damietta University, Egypt. 3- National Institute of Oceanography and Fisheries, Egypt *Corresponding author: basmasheta@du.edu.eg ARTICLE INFO ABSTRACT Article History: Received: April 28, 2019 Accepted: May 12, 2019 Online: May 18, 2019 _______________ Keywords: Oreochromis niloticus Phytoremediation Ceratophyllum demersum Lemna minor Aquaculture Wastewater Pollution Two aquatic macrophytes, Ceratophyllum demersum and Lemna minor, were used in aquaculture wastewater treatment. Tilapia fish (Oreochromis niloticus) with total body weight of 50-60 g were placed in 60 L aquaria. Four treatment groups were included: control (no plant treatment, depended on artificial filtering for purification), Lemna minor (Lm), Ceratophyllum demersum (Cd), and mixed plants group (Lm+Cd). Each group had three replicates (5 fish/replicate). The experiment was conducted for 4 weeks. Physicochemical parameters of aquaculture wastewater including pH, total dissolved solids (TDS), conductivity, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphorous (TPO 4 ), nitrate (NO 3 ), nitrite (NO 2 ), and ammonia were determined. The results reflected more effective removal of pollutants from fish aquaria by both plants than that by the artificial aeration/filtering. The effectiveness of pollution removal was higher in Cd group > Lm > Lm+Cd, compared to the control. This order of phytoremediation was confirmed by improvements in tilapia fish health status including liver function (AST, ALT, albumin), kidney function (creatinine, urea, uric acid), in addition to other nutritional and hematological parameters. It could be concluded that the phytoremediation using C. demersum is ecofriendly and effective in removing contaminants from Tilapia aquaculture wastewater and therefore, it is recommended to be applied in tilapia farms. INTRODUCTION Huge amounts of freshwater are required for intensive aquacultures, which generate nutrient-rich wastewater streams, causing eutrophication and negatively impact aquatic biological communities. Reduction of nutrient and chemical discharge into receiving water bodies always needs sustainable water treatment technologies (Islam and Tanaka 2004, and Wuang et al., 2016). In this context, aquatic plants have been widely used to remove pollutants from wastewaters. Floating and emergent plants have been studied for nutrient and heavy metal removal from different types of wastewater (Seo et al., 2010; Tel-Or and Forni, 2011). Pollutant removal studies by aquatic plants have been applied on aquaculture pond effluent (Sooknah and Wilkie, 2004; Mohedano et al., 2012). Iamchaturapatr et al. (2007) examined diverse types