Polyhydroxyalkanoate biosynthesis from paper mill wastewater treated by a moving bed biofilm reactor

Abstract

Polyhydroxyalkanoate (PHA) biosynthesis in paper mill wastewater treated by a Moving Bed Biofilm Reactor (MBBR) was evaluated. A MBBR was operated during 300 d. The increasing effect of the Organic Load Rate (OLR) from 0.13 kg BOD₅/m³·d to 2.99 kg BOD₅/m³·d and the influence of two relationship of BOD_5: N: P (100: 5: 1 and 100: 1: 0.3) on the PHA biosynthesis were evaluated. With an OLR of 0.13 kg BOD₅/m³·d, the maximum organic matter removal measure as Biochemical Oxygen Demand (BOD₅) was 98.7% for a BOD_5: N: P relationship of 100: 5: 1. Meanwhile for BOD₅: N: P relationship of 100: 1: 0.3, the maximum efficiency was 87.2% (OLR: 2.99 kg BOD₅/m³·d). The behaviour of the Chemical Oxygen Demand (COD) and total phenolic compound removal efficiencies were below 65.0% and 41.0%, respectively. PHA biosynthesis was measured as a percentage of cells that accumulate PHA, where the maximum percentage was 85.1% and 78.7% when MBBR was operated under a BOD₅: N: P relationship of 100: 5: 1 and 100: 1: 0.3, respectively. Finally, the PHA yields in this study were estimated to range between 0.11 to 0.72 mg PHA/mg VSS and 0.06 to 0.15 mg PHA/mg COD.

Keywords:

• Paper mill wastewater
• MBBR
• sludge
• polyhybroxyalkanoates
• organic matter

Acknowledgments

This work was supported by Fondecyt Grant No. 1120664, CONICYT AT Grant No. 24100082.