Polyhydroxyalkanoate (PHA) production from tapioca industrial wastewater treatment: Influence of operating conditions on PHA content

The aims of these experiments were treating tapioca processing waste water to produce polyhydroxyalkanoates (PHAs) and removal of chemical oxygen demand (COD). The experiments were conducted in a sequencing batch reactor with a volume of 6 L. The entire experimental condition was anaerobic-aerobic-anaerobic. Experiment 1, 2 and 3 had the first 2 h for feeding time while Experiment 4 had 3 h. The 4 h between feeding time and settling time were variation of aeration time and without aeration. Experiment 1 had 2 h aeration time and 2 h without aeration. Experiment 2 has 1 h aeration and 3 h without aeration. Experiment 3 had 1 h interval alternating between aeration time and no aeration. Experiment 4 had 2 h aeration and 1 h no aeration. The first 6 h was mixing, the last 3 h was settling and draining time with total operating time 9 h. The experiments found that the average of PHA contents in Experiment 1, 2, 3, and 4 were -1 0.102, 0.043, 0.04, and 0.031 g PHA g MLSS (mixed liquor suspended solids), respectively. The -1 maximum value in Experiment 1 was 0.3 g PHA g MLSS. The average COD removal of experiment 1, 2, 3, and 4 was 26, 37, 23, and 18%, respectively. .