Assessment of Phosphate Laundries Wastewater Phytotoxicity and Biotreatment Assays

• Published in: Clean : soil, air, water air, water, 2020-11, Vol.48 (11), p.n/a
• Main Authors: Moula, Amel, Borgi, Mohamed Ali, Loukil, Slim, Chaieb, Mohamed, Mekki, Ali
• Format: Article
• Language: English
• Subjects: Alfalfa; Bioprocessing; Cadmium; Calcium; Correlation analysis; Detoxification; Enumeration; Germination; Heavy metals; microbial detoxification; Microflora; Microorganisms; phosphate laundries wastewater; Phosphates; Phytotoxicity; Potassium; potentially toxic metals; Seeds; Sorghum; Suspended matter; Toxicity; Wastewater; Zinc
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.202000077

The phytotoxicity potential of phosphate laundries wastewater (PLW) is assessed. Likewise, the assays of biotreatment of the PLW by microbial detoxification are investigated. Chemical characterization results show that PLW are alkaline, saline, highly turbid, and rich in suspended matter and total solids. PLW samples are loaded with potentially toxic metals, presented in decreasing order as follows: calcium (1230 mg L−1), potassium (1032 mg L−1), iron (275.45 mg L−1), lead (1.64 mg L−1), zinc (1.12 mg L−1), copper (1.04 mg L−1), and cadmium (1.03 mg L−1). Besides, PLW exhibits high phytotoxicity values for Raphanus sativus, Medicago sativa, and Sorghum bicolor seeds germination. The microbiological enumeration reveals considerable autochthonous microflora. Biotreatment includes five selected native strains (Se, S16, S19, S20, and S29) used as a tool of PLW detoxification. The strains tested manifest a bioprocessing performance according to the following decreasing order: S29 > S16 > S20 > S19 > Se. The biotreated phosphate laundries wastewater (BTPLW) achieves a noticeable reduction of toxicity. Indeed, analysis of the correlation matrix between the potentially toxic metal content and the germination index (GI) values shows significant correlations (p ≤ 0.01). Phosphates industry is one of the most important sectors in Tunisia. The phosphate laundries wastewaters constitute a serious environmental problem. The biotreatment technology constitutes a potential process for wastewater detoxification. The microbiological detoxification process provides a non‐phytotoxic effluent.