The investigation of coagulationflocculation and dissolved air flotation techniques for water reuse in the textile industry

• Main Author: Lee, Xue Li
• Format: Final Year Project / Dissertation / Thesis
• Published: 2023
• Subjects: TP Chemical technology
• Online Access: http://eprints.utar.edu.my/5574/1/1804463_FYP_Report.pdf; http://eprints.utar.edu.my/5574/

Significant water consumption and high-coloured effluent discharge remain the main concern of the textile industry as it might provide negative impacts on the environment due to the improper treatment of textile effluent. To reduce the water insecurity of global, this study investigated the performance of coagulation-flocculation and dissolved air flotation (DAF) in treating textile wastewater to determine whether the treatment method is suitable for water reuse purposed. The parameter studies on coagulation-flocculation were studied to determine the optimized operating condition of the process. The effect of types of natural flocculants (cactus, banana peel, moringa oleifera seed), types of coagulants (aluminium sulphate, ferric chloride, polualuminium chloride (PAC)), presence of flocculant and chemical conventional flocculant (ferric chloride, ferric chloride + banana peel, ferric chloride + polyacrylamide (PAM)), dosage of flocculant (10, 20, 30, 50, 70 mg/L), dosage of coagulant (50, 75, 100, 150, 200 mg/L) and solution pH (3, 5, 6, 7, 8, 9, 11) were studied using a flocculation test unit. Besides, the surface morphology and crystallinity of natural flocculants were characterised using SEM-EDX and XRD. By comparing the process efficiency in terms of turbidity, COD and colour percentage removal, the coagulation-flocculation process with 150 mg/L of ferric chloride, 20 mg/L of banana peel at pH 7 was determined as the optimum condition for treatment of textile wastewater. After that, the performance of combined coagulation-flocculation and DAF was studied. The percentage removal of turbidity, COD and colour of treated water sample after DAF was found higher than before DAF. The DAF process increased the percentage removal of turbidity, COD and colour from 95.71 % to 97.43 %, 18.52% to 64.44 % and 55.00 % to 63.57 %, respectively. Water reuse of treated textile wastewater can be obtained as the COD value of 6 mg/L and colour of 17 ADMI were below the Malaysia sewage and industrial discharge standards A.