Biotechnological Assessment of the Efficiency of Medicinal Plant Extracts as Natural Bio-Flocculants in Sustainable Water Treatment

Valorization of green plantain waste for natural dye production with potential applications in the textile industry

Global plantain production reaches approximately 44.6 Mt annually, of which an estimated 30–40% corresponds to peel waste, highlighting the urgent need for effective valorization strategies for this underutilized biomass. In this context, this study evaluates the laboratory-scale feasibility of producing a natural dye from green plantain peel and demonstrates its potential application in the textile industry. A comparative approach was employed, including conventional reflux extraction and enzyme-assisted extraction using cellulase, enabling a systematic assessment of extraction performance and dyeing behavior. Although the extract obtained without enzymatic treatment showed higher concentrations of tannins and flavonoids, the enzymatically treated sample exhibited improved dye quality, with enhanced purity and superior color fixation on cotton fabrics. Dye performance was assessed according to ISO 105-C10:2006 and ISO 105-E07:2010, demonstrating improved washing fastness and consistent coloration within the pink spectrum for the enzymatic extract. The main contribution of this work lies in demonstrating that enzymatic pretreatment can significantly enhance the functional performance of plantain peel-derived dyes, despite lower concentrations of chromophoric compounds, highlighting the importance of extract quality over composition alone. Furthermore, this study provides a novel and integrated approach for the valorization of green plantain peel waste, combining process optimization and textile performance evaluation. These findings contribute to the development of sustainable dyeing alternatives and support the implementation of circular economy strategies in the textile sector.

Evaluating the Application of Cationic Acacia Tannins in Wastewater Treatment as Bio-Based Alternative to Synthetic Flocculants

Polyacrylamide (PAM), the most widely used flocculant in wastewater treatment, has raised sustainability concerns because it is derived from fossil-based raw materials. This study evaluated cationic tannins derived from Acacia as a bio-based alternative to PAM for the chemical treatment of dairy wastewater. Jar tests combined with design of experiments (DoE) and response surface optimization were used to investigate the effects of FeCl3, PAM, and tannin dosages on the removal of suspended solids (Susp), total phosphorus (TP), and chemical oxygen demand (COD). Samples were subjected to rapid mixing (150 rpm, 2 min), followed by slow mixing (80 rpm, 5 min) and a sedimentation time of 30 min. The combination of 360 µL L−1 FeCl3 and 100 mg L−1 tannins achieved treatment efficiencies comparable to those obtained with 360 µL L−1 FeCl3 and 25 mg L−1 PAM, indicating that approximately four times more tannin than PAM was required. At optimized FeCl3–tannin dosages, removal efficiencies approaching 100% for Susp, TP, and COD were obtained. Tannins used without FeCl3 achieved approximately 98%, 70%, and 76% removal of Susp, TP, and COD, respectively. Treatment costs were estimated at 2.78 SEK m3 for the FeCl3–tannin system compared with 1.83 SEK m3 for the FeCl3–PAM system, corresponding to an additional cost of approximately 0.09 € /m3. However, costs could be reduced by optimizing the FeCl3-to-tannin ratio. Furthermore, sludge containing 100–200 mg L−1 tannins showed enhanced biogas production. These results demonstrate that cationic Acacia tannins are a promising bio-based alternative to synthetic flocculants for dairy wastewater treatment, although further optimization and more full-scale validation are required.

THE USE OF MORINGA OLEIFERA SEED EXTRACT AS A NATURAL COAGULANT TO REDUCE BACTERIOLOGICAL CONTAMINATION IN RIVER WATER

Efficacy of Citrullus Lanatus (Water Melon Seed) Extract as Natural Bio-Coagulant for Physiochemical Characterization in Water Treatment System

There has been a growing concern for environmental and health associated conventional chemical coagulants such as alum and the search for sustainable plant-based alternatives for water treatment process have intensified. Consequently, the objective of this paper investigated the efficacy of WMS extract as a natural bio-coagulant for physicochemical characterization in water treatment system. WMS powder was characterized using FTIR spectroscopy (Agilent Cary 630, ATR mode) and XRF spectrometry (CrossRoads Scientific XRS-FP) to identify functional groups and elemental composition relevant to the coagulation mechanism. Coagulation performance was assessed using the standard jar test method at different dosages of 10, 20, 30, and 40 mg/L respectively applied to synthetic turbid water (115 NTU, kaolin based), with alum as the reference coagulant. FTIR analysis confirmed a multi-functional composition comprising proteins (Amide I: 1621-1636 cm⁻¹; Amide II: 1509-1543 cm⁻¹), polysaccharides (C-O-C: 1040-1065 cm⁻¹), lipids (C-H: 2850-2930 cm⁻¹), phosphate groups (965-995 cm⁻¹), and hydroxyl/amine groups (3200-3500 cm⁻¹). XRF analysis identified major element constituents as SO3 (25.783 wt %), K2O (17.615 wt%), SiO2 (17.542 wt%), P2O5 (9.814 wt%), Al2O3 (8.960 wt%), CaO (7.934 wt%), and Fe2O3 (4.720 wt%), indicating synergistic organic and inorganic coagulation contributions. WMS achieved a maximum turbidity removal efficiency of 97.5% at 30 mg/L (3 NTU), compared to alum's 98.4% at 20 mg/L, meeting the WHO guideline of 5 NTU in both case. Lower volume sludge amenable to agricultural reuse. These findings establish WMS as a sustainable alternative to alum.

Reuse of reclaimed wastewater for sustainable irrigation of basil (Ocimum basilicum): effects on plant performance and yield

Water scarcity is a major challenge to agriculture, emphasizing the need for innovative solutions such as wastewater reuse. This study evaluates the potential of biologically treated sewage water from the El-Salam Canal (Al-Sharqia, Egypt) for safe irrigation using the microalga Chlorella vulgaris and the bacterium Bacillus megaterium as eco-friendly remediation agents. Biological treatment of wastewater was conducted using Chlorella vulgaris and Bacillus megaterium, and the removal efficiency of nutrients and heavy metals was assessed. A pot experiment was performed using basil (Ocimum basilicum) irrigated with domestic water, untreated wastewater, and bio-treated wastewater. Plant growth parameters, chlorophyll content, proline, antioxidant enzymes, oil production, microbial rhizosphere soil activity, soil properties, and heavy metal accumulation in soil and leaves were evaluated. Phycoremediation significantly improved effluent quality, with Chlorella vulgaris reducing nitrogen, phosphorus, and heavy metals by 41.1%, 46.7%, and 37.5%, respectively, while Bacillus megaterium achieved reductions of 32.3%, 39.2%, and 28.4%. In a pot experiment with basil (Ocimum basilicum), untreated wastewater significantly inhibited growth, biomass, and chlorophyll content, and increased proline and antioxidant enzymes. In contrast, plants irrigated with bio-treated wastewater showed rapid growth, with Chlorellavulgaris achieving the highest improvement in height, dry weight, chlorophyll, and oil production. Bacillus megaterium enhanced rhizosphere activity by increasing dehydrogenase activity, indole acetic acid production, and micronutrient levels. Treated wastewater resulted in growth comparable to domestic water and significantly reduced heavy metal accumulation in soil and leaves. The results demonstrate that phycoremediation with Chlorella vulgaris and Bacillus megaterium can convert wastewater into a safe and nutrient-rich resource, reducing environmental risks and phytotoxicity. This approach offers a sustainable and climate-resilient strategy for agriculture in water-deficient regions like Egypt.

A STUDY OF THE EFFECTIVENESS OF MICROALGAE IN REMOVING HEAVY METALS FROM WASTEWATER FROM MECHANICAL ENGINEERING PLANTS

This review article examines modern research on the problem of wastewater pollution from machine-building enterprises with heavy metals and the possibilities of their biological purification using microalgae. The main sources of industrial wastewater formation, their chemical composition and approximate maximum permissible concentrations of pollutants are analyzed. The limitations of traditional physico-chemical cleaning methods are considered. The work describes in detail the mechanisms of bioremediation involving microalgae, including the processes of biosorption, bioaccumulation and complexation.Data on Chlorella vulgaris biological characteristics, resistance to contamination, and high efficiency of heavy metal removal under various conditions are presented. A comparison of the effectiveness of different types of microalgae is presented. The advantages and limitations of microalgae purification in terms of environmental safety, economic feasibility and resistance to changing environmental conditions are analyzed.In conclusion, the use of Chlorella vulgaris for environmentally safe and cost-effective wastewater treatment from heavy metals is considered promising, and the need for further research in this area is emphasized.