Polyhydroxyalkanoate production from fermentation of domestic sewage sludge monitoring greenhouse gas emissions: A pilot plant case study at the WRRF of Palermo University (Italy).

This paper presents a comprehensive study on polyhydroxyalkanoate (PHA) production from sewage sludge. Greenhouse gas (GHG) emissions were monitored for the first time to assess the impact of climate change and environmental sustainability. The pilot plant was composed of a fermenter with a membrane and two biological reactors (namely, selection and accumulation). Results showed that despite a low organic loading rate (namely, 0.06 kg BOD kg SS−1 day−1), a good PHA yield was obtained (namely, 0.37 g PHA/g volatile fatty acids), confirming that sewage sludge can be a suitable feedstock. GHG emissions were 3.85E-04 g CO 2 eq/g and 32.40 g CO 2 eq/g, direct and indirect, respectively. Results provided valuable insights in view of finding a trade-off between PHA production and GHG emissions to prove the PHA production process as an effective solution for biosolids disposal at a low carbon footprint. [Display omitted] • Sewage sludge acidogenic fermentation at low carbon footprint was performed. • High COD, ammonia and phosphate removal was achieved. • Final PHA concentration of 0.37 g PHA/g VSS was obtained. • N 2 O emission factor accounted for less than 1 % of total nitrogen. • N 2 O direct and indirect emissions were 3.85E-04 and 32.40 g CO2eq/g treated sludge. [ABSTRACT FROM AUTHOR]