Development of a Novel Process Integrating the Treatment of Sludge Reject Water and the Production of Polyhydroxyalkanoates (PHAs).
Polyhydroxyalkanoates (PHAs) from activated sludge and renewable organic material can become an alternative product to traditional plastics since they are biodegradable and are produced from renewable sources. In this work, the selection of PHA storing bacteria was integrated with the side stream treatment of nitrogen removal via nitrite from sewage sludge reject water. A novel process was developed and applied where the alternation of aerobic-feast and anoxic-famine conditions accomplished the selection of PHA storing biomass and nitrogen removal via nitrite. Two configurations were examined: in configuration 1 the ammonium conversion to nitrite occurred in the same reactor in which the PHA selection process occurred, while in configuration 2 two separate reactors were used. The results showed that the selection of PHA storing biomass was successful in both configurations, while the nitrogen removal efficiency was much higher (almost 90%) in configuration 2. The PHA selection degree was evaluated by the volatile fatty acid (VFA) uptake rate (-qVFAs) and the PHA production rate (qPHA), which were 239 ± 74 and 89 ± 7 mg of COD per gram of active biomass (Xa) per hour, respectively. The characterization of the biopolymer recovered after the accumulation step, showed that it was composed of 3-hydroxybutyrate (3HB) (60%) and 3-hydroxyvalerate (3HV) (40%). The properties associated with the produced PHA suggest that they are suitable for thermoplastic processing.
University of Verona , Department of Biotechnology, Strada Le Grazie 15, 37134 Verona, Italy.
Nicola
N
Frison
University of Verona , Department of Biotechnology, Strada Le Grazie 15, 37134 Verona, Italy.|Department of Mechanical, Aerospace and Civil Engineering, Brunel University , Kingston Lane, UB8 3PH Uxbridge, Middlesex, U.K.
Evina
E
Katsou
University of Verona , Department of Biotechnology, Strada Le Grazie 15, 37134 Verona, Italy.|Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens , 5 Iroon Polytechniou St., 15780, Athens, Greece.
Simos
S
Malamis
UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , 2829-516 Caparica, Portugal.
Adrian
A
Oehmen
University of Verona , Department of Biotechnology, Strada Le Grazie 15, 37134 Verona, Italy.
Francesco
F
Fatone
D000332:Aerobiosis; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D018533:Biomass; D001704:Biopolymers; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods*; D005232:Fatty Acids, Volatile; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis / Q000302:isolation & purification; D010421:Pentanoic Acids; D054813:Polyhydroxyalkanoates / Q000737:chemistry / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
D001704:Biopolymers; D005232:Fatty Acids, Volatile; D009573:Nitrites; D010421:Pentanoic Acids; D054813:Polyhydroxyalkanoates; D012722:Sewage; C013056:beta-hydroxyvaleric acid; D009584:Nitrogen