Microalgae cultivation is well known as a sustainable method for eco-friendly wastewater phycoremediation and valuable biomass production. This study investigates the feasibility and kinetic removal of organic compounds and nutrients from food processing wastewater (FPW) using Botryococcus sp. in an enclosed photobioreactor. Simultaneously, response surface methodology (RSM) via face-centered central composite design (FCCCD) was applied to optimize the effects of alum and chitosan dosage and pH sensitivity on flocculation efficiency. The maximum growth rate of Botryococcus sp. cultivated in FPW was 1.83 mg day-1with the highest removal of chemical oxygen demand (COD), total organic carbon (TOC), and total phosphorus (TP) after 12 days of phycoremediation of 96.1%, 87.2%, and 35.4%, respectively. A second-order polynomial function fits well with the experimental results. Both coagulant dosage and pH significantly (p < 0.05) affect the flocculation efficiency of Botryococcus sp. biomass cultivated in FPW. The highest flocculation efficiency (92.4%) was obtained at a dosage of 166 mg L-1and pH 12 for alum coagulant, while 94.9% flocculation efficiency was achieved with optimum chitosan dosage and pH of 30 mg L-1and 5.54, respectively. In general, Botryococcus sp. shows a great removal efficiency of FPW contamination, whereas RSM provides excellent analysis for biomass harvesting optimization using a flocculation technique.
Keywords: Biomass; Botryococcus sp.; flocculation; food wastewater; phycoremediation; response surface methodology.
Eutrophication is caused by an overabundance of organic compounds and nutrients such as chemical oxygen demand, total nitrogen, phosphorus and total organic carbon in food processing wastewater (FPW) that is discharged into natural water systems. Although, there has been few research on the phycoremediation using Botryococcus sp. in wastewater treatment. Hence, the current study was carried out to investigate Botryoccocus sp. biomass harvesting efficiency using alum and chitosan as flocculants after the nutrients and organic compounds removal were analyzed during phycoremediation. The use of response surface methodology also offers excellent statistical analysis for flocculation optimization.