Response surface methodology for the elimination of humic substances from water by coagulation using powdered Saddled sea bream scale as coagulant-aid

• The powdered Saddled sea bream scale was used as coagulant-aid.
• The removal efficiency depends on the chemical structure of organic components.
• The PFS seems to be an alternative adsorbent for the elimination of HS.
• The response surface methodology was applied to optimize the coagulation process.

Removal of organic substances from water by coagulation with alum and ferric salts were studied by means of conventional jar-test procedures.The novelty of this work is the use of powdered Saddled sea bream scale as coagulant-aid for enhancing the coagulation process with a low concentration of alum (Al2(SO4)3·18H2O).Performance of usual coagulation process depends on the chemical structure of organic components as phenol (PHL), salicylic acid (SA), phthalic acid (PHA) and humic substances (HS), their initial concentrations, coagulant dose, pH medium, and other operational conditions.The response surface methodology (RSM) was applied to optimize the coagulation process for the elimination of humic substances from water. Initial HS concentration, alum dose, rapid and slow mixing speed, powdered fish scales (PFS) mass and pH were the factors considered in the design.A quadratic model was developed to express the removal efficiency of HS (response Y) as function of the six parameters. The high values of R2 and R2 adjusted coefficients verify a good correlation between the observed and the predicted response values.