ABSTRACT
Coagulation/flocculation is a major phenomenon that occurs in industrial and municipal water treatment to remove suspended solids. The use of conventional metal-based coagulants/flocculants is valued for its high performance, low cost, ease of use, availability and effectiveness. However, it is currently raising new concerns. The alarming issues of prolonged effects on human health and increased pollution of aquatic environments by the large quantities of non-biodegradable sludge generated are becoming hot topics. As a result, alternative coagulants and flocculants, called biocoagulants and bioflocculants because of their biological origin and biodegradability, have recently been developed for water and wastewater treatment. The objective of this study is the treatment of wastewater from the STEP of Ain Baida Harriche – Ferdjioua, Mila wilaya, in the region of Constantine in Algeria, after pretreatment steps (screening, grinting and oil removal) using the carob as a biocoagulant. The characterization of the carob powder was made through the determination of the surface group functions by the Bohem method which showed the acid character containing carboxylics and phenols. FTIR spectroscopy analysis indicated the presence of polysaccharides and proteins causing coagulation. The value of zero-point pH of carob was equal to 5.5 confirming the low acid nature. Results showed that the biocoagulation bioflocultion treatment could be technically and economically feasible since efficiencies of turbidity, chemical oxygen demand, and phenol removal of 78.80, 80.18 and 78.41% respectively could be achieved using an optimal coagulant dose of 20 mg/L of carob and pH = 8.
It can be concluded that using the carob as a low-cost material into the coagulation/flocculation process can offer some advantages such as high treatment efficiency and economic savings on overall treatment plant operation costs.
