Optimization of immobilized activated sludge performance in electro-sprayed matrices for treatment of cellulose industry wastewater

Today, the abundant use of cellulose industry products has led to an increase in production and, as a result, an increase in the volume of water consumed by this industry. On the other hand, the high volumetric flow rate of produced wastewater, chemical oxygen demand (COD), suspended solids and high turbidity of these wastewaters have caused many problems. In recent years, various methods, including physical, chemical and biological, have been used for wastewater treatment. In this study, firstly, the efficiency of the activated sludge collected from cellulose wastewater was investigated in freely suspended cell system in shake flask experiments at 150 rpm and 30 °C. Afterward, to investigate the performance of immobilized sludge, alginate and hybrid alginate-polyvinyl alcohol polymers were used for microbeads production. In this survey, the electrospray technique and response surface methodology (RSM) were employed to produce microbeads and statistical optimization, respectively. In order to optimize the bioremediation process, three variables including electrospray voltage (0-12 kV), the volume of cell-polymer suspension (1-3 mL), and two type of carriers were selected. In order to analyze the wastewater, the results related to COD were evaluated. The optimization results showed that the maximum biodegradation and COD removal of 74% (from 6715 to 1736 mg/L) after 4 days was observed by the alginate-immobilized cells produced with the voltage and polymer-cell solution volume of 3 kV and 2.5 mL, respectively.