| Title | Techno-environmental assessment of integrating polyhydroxyalkanoate (PHA) production with services of municipal wastewater treatment |
| Abstract | In this paper, the potential impacts in the techno-environmental performance of a municipal wastewater treatment plant with integrated mixed-microbial-culture polyhydroxyalkanoate (PHA) production are presented for the first time. A life cycle assessment was conducted based on mass and energy balances. The techno-environmental performance was evaluated for five wastewater treatment configurations: a reference case and four alternative processes producing PHA-rich biomass using influent municipal wastewater as the only organic carbon source. The integration of PHA-rich biomass production into a municipal wastewater treatment plant with sludge digestion sustains the overall conversion yield for total products of biogas and PHA-rich biomass (around 0.26 gCOD products per influent gCOD treated). PHA production integration has the potential to improve the overall environmental performance with respect to the reference case. Even when no benefits were accounted for substitutions related to the biogas and PHA-rich biomass, similar or improved environmental performances were estimated for all four alternatives for global warming potential, acidification potential, terrestrial eutrophication potential, and photo-oxidant formation potential. When benefits were accounted from substitutions of electricity and heat co-generated from biogas and of PHA-rich biomass by pure-culture PHA-rich biomass from sugar fermentation, gains were even higher due to the diversion of carbon from biogas to PHA-rich biomass. Freshwater and marine eutrophication potentials were dependent on effluent specifications. Case-by-case process configurations influence the mass and energy balance and trade-offs of process integration. The production and export of PHA-rich biomass decreased the aeration requirements for COD and nitrogen removal; however, increased demands for heat, power and chemicals were incurred for the generation of volatile fatty acids from primary solids fermentation. The choice of nitrogen-removal approach (nitrification-denitrification vs. anammox) also impacted energy consumption. Using influent wastewater as the sole carbon supply, the energy balance and PHA production were sensitive to the efficiency of primary treatment and available flux of volatile fatty acids into PHA production. Other regional inputs of organic residuals may improve carbon recovery in the treatment facility. The improved environmental performance of the treatment configurations motivates the idea that individual municipal wastewater treatment plants may become suppliers of renewable raw materials of higher value than that of biogas and/or energy and heat today. |
| Source | Journal of cleaner production 137, pp. 1368–1381 |
| Keywords | Activated sludgeBio-basedLife cycle assessment (LCA)Nitrogen/phosphorus managementPolyhydroxyalkanoate (PHA)Resource recovery |
| Journal | Journal of cleaner production |
| Editor | Butterworth-Heinemann,, Oxford, Regno Unito |
| Year | 2016 |
| Type | Articolo in rivista |
| DOI | 10.1016/j.jclepro.2016.08.008 |
| Authors | Morgan-Sagastume, Fernando; Heimersson, Sara; Laera, Giuseppe; Werker, Alan; Werker, Alan; Svanström, Magdalena |
| Text | 366958 2016 10.1016/j.jclepro.2016.08.008 Scopus 2 s2.0 84990942871 ISI Web of Science WOS 000391079300123 Activated sludge Bio based Life cycle assessment LCA Nitrogen/phosphorus management Polyhydroxyalkanoate PHA Resource recovery Techno environmental assessment of integrating polyhydroxyalkanoate PHA production with services of municipal wastewater treatment Morgan Sagastume, Fernando; Heimersson, Sara; Laera, Giuseppe; Werker, Alan; Werker, Alan; Svanstrom, Magdalena AnoxKaldnes AB; Chalmers University of Technology; Istituto di Ricerca Sulle Acque, Bari; University of Queensland In this paper, the potential impacts in the techno environmental performance of a municipal wastewater treatment plant with integrated mixed microbial culture polyhydroxyalkanoate PHA production are presented for the first time. A life cycle assessment was conducted based on mass and energy balances. The techno environmental performance was evaluated for five wastewater treatment configurations a reference case and four alternative processes producing PHA rich biomass using influent municipal wastewater as the only organic carbon source. The integration of PHA rich biomass production into a municipal wastewater treatment plant with sludge digestion sustains the overall conversion yield for total products of biogas and PHA rich biomass around 0.26 gCOD products per influent gCOD treated . PHA production integration has the potential to improve the overall environmental performance with respect to the reference case. Even when no benefits were accounted for substitutions related to the biogas and PHA rich biomass, similar or improved environmental performances were estimated for all four alternatives for global warming potential, acidification potential, terrestrial eutrophication potential, and photo oxidant formation potential. When benefits were accounted from substitutions of electricity and heat co generated from biogas and of PHA rich biomass by pure culture PHA rich biomass from sugar fermentation, gains were even higher due to the diversion of carbon from biogas to PHA rich biomass. Freshwater and marine eutrophication potentials were dependent on effluent specifications. Case by case process configurations influence the mass and energy balance and trade offs of process integration. The production and export of PHA rich biomass decreased the aeration requirements for COD and nitrogen removal; however, increased demands for heat, power and chemicals were incurred for the generation of volatile fatty acids from primary solids fermentation. The choice of nitrogen removal approach nitrification denitrification vs. anammox also impacted energy consumption. Using influent wastewater as the sole carbon supply, the energy balance and PHA production were sensitive to the efficiency of primary treatment and available flux of volatile fatty acids into PHA production. Other regional inputs of organic residuals may improve carbon recovery in the treatment facility. The improved environmental performance of the treatment configurations motivates the idea that individual municipal wastewater treatment plants may become suppliers of renewable raw materials of higher value than that of biogas and/or energy and heat today. 137 Published version https //doi.org/10.1016/j.jclepro.2016.08.008 2016 JCP 137, 1368 1381 Morgan Sagastume et al Versione pubblicata dall Editore 2016 JCP 137, 1368 1381 Morgan Sagastume et al.pdf Articolo in rivista Butterworth Heinemann, 0959 6526 Journal of cleaner production Journal of cleaner production J. clean. prod. Journal of cleaner production. giuseppe.laera LAERA GIUSEPPE |
