A model and tool to calculate life cycle inventories of chemicals discharged down the drain
- 736 Downloads
The aim of this article is to present a new model and tool to calculate life cycle inventories (LCIs) of chemicals discharged down the drain. Exchanges with the technosphere and the environment are attributed for based on the predicted behaviour of individual chemicals in the wastewater treatment plant (WWTP) and following discharge to the aquatic environment, either through the treated effluent or directly when there is no connection to WWTP. The described model is programmed in a stand-alone spreadsheet, WW LCI.
The model includes treatment in a modern WWTP and sludge disposal as well as the greenhouse gas (GHG) and nutrient emissions from degradation in the environment. The model fundamentals are described, and its application is shown with six industrial chemicals: sodium carbonate, ethanol, tetraacetylethylenediamine (TAED), diethylenetriamine penta(methylene phosphonic acid) (DTPMP), zeolite A and sodium tripolyphosphate (STPP). This application considers two scenarios: Germany, with full connection to WWTP, and a generic direct discharge scenario. The scenario with WWTP connection is assessed with WW LCI as well as with the wastewater treatment model developed for ecoinvent. Results are presented for key LCI flows and for life cycle impact assessment (LCIA), focusing on GHG emissions, freshwater ecotoxicity and marine and freshwater eutrophication.
Results and discussion
GHG emissions predicted by WW LCI differ to those predicted by the ecoinvent model, with the exception of sodium carbonate. For zeolite A and DTPMP, WW LCI predicts GHG emissions 330 higher and 12.5 times lower, respectively. Eutrophication scores are lower for WW LCI as the German scenario considers more optimistic nutrient removal rates than the default ones from the ecoinvent model. Freshwater ecotoxicity is mainly driven by the magnitude of the USEtox characterization factors; however, the ecoinvent model cannot accommodate chemical-specific toxicity assessments. When WW LCI is used to compare a direct discharge scenario with the German scenario, differences are found in all three impact categories.
WW LCI provides a comprehensive and chemical-specific inventory, constituting an advance over previous models using generic descriptors such as biological oxygen demand. This level of detail comes at the price of an increased effort for collecting input data as well as the need to identify individual chemicals in wastewater prior to the assessment. The LCIs generated through this model can then be applied in the context of LCA studies where each chemical contributes to the total life cycle impacts of a product or service.
KeywordsEnvironmental fate model LCI Life cycle assessment Sewage Wastewater WW LCI
- AISE (2015) PEF screening report in the context of the EU Product Environmental Footprint Category Rules (PEFCR) Pilots Household Heavy Duty Liquid Laundry Detergents (HDLLD) for machine wash. Report submitted on April 8, 2015 by AISE to the EU PEF stakeholders wikipage. https://webgate.ec.europa.eu/fpfis/wikis/display/EUENVFP/Stakeholder+workspace%3A+PEFCR+pilot+Household+liquid+laundry+detergents (accessed 17 September 2015)
- Birkved M, Gallice A, Kech S, Hauschild MZ (2015) SewageLCI 1.0—a first generation inventory model for quantification of chemical emissions via sewage systems. Int J Life Cycle Assess, submittedGoogle Scholar
- Daigger GT (1998) Upgrading wastewater treatment plants, second edition. CRC PressGoogle Scholar
- Dalemo M (1997) The ORWARE simulation model. Anaerobic digestion and sewage plant sub-models. Licenthiate thesis. Swedish Institute of Agricultural Engineering, Swedish University of Agricultural Sciences (SLU), Uppsala. AFR-report 152, Swedish Environmental Protection AgencyGoogle Scholar
- Doka G (2007) Life cycle inventories of waste treatment services. Final report ecoinvent 2000 No. 13, EMPA St. Gallen, Swiss Centre for Life Cycle Inventories, Duebendorf, SwitzerlandGoogle Scholar
- Droste RL (1997). Theory and practice of water and wastewater treatment. John Wiley and Sons, Inc.Google Scholar
- Ecoinvent Centre (2015) The ecoinvent Database. http://www.ecoinvent.org
- Eurostat (2015a) Population connected to wastewater treatment plants (env_ww_con). http://ec.europa.eu/eurostat/data/database (Accessed 31 August 2015)
- Eurostat (2015b) Sewage sludge production and disposal (env_ww_spd). http://ec.europa.eu/eurostat/data/database (Accessed 31 August 2015)
- FAO & IFA (2001) Global estimates of gaseous emissions of NH3, NO and N2O from agricultural land. Food and Agriculture Organization of the United Nations (FAO) and International Fertilizer Industry Association (IFA). RomeGoogle Scholar
- Franco A, Struijs J, Gouin T, Price OR (2013b) Evolution of the sewage treatment plant model SimpleTreat: use of realistic biodegradability tests in probabilistic model simulations. Integr Environ Assess Manag 9999(9999):1–11Google Scholar
- Goedkoop MJ, Heijungs R, Huijbregts M, De Schryver A, Struijs J, Van Zelm R (2013) ReCiPe 2008 a life cycle impact assessment method which comprises harmonized category indicators at the midpoint and the endpoint level. First edition (version 1.08) Report I: Characterisation. Ministerie van VROM, Den Haag, The NetherlandsGoogle Scholar
- Hopkowicz M (2000) Energy management at WWTP with biogas utilisation. In: Proceedings of a Polish-Swedish seminar, Cracow, May 29, 2000. Sustainable Municipal Sludge And Solid Waste Handling, E. Plaza, E. Levlin, B. Hultman, (Editors), TRITA-AMI REPORT 3073, ISSN 1400–1306, ISRN KTH/AMI/REPORT 3073-SE, ISBN 91–7170–584-8. 2000. http://www2.lwr.kth.se/forskningsprojekt/Polishproject/JPS7s43.pdf (accessed 3 August 2015)
- IPCC (2006) 2006 IPCC guidelines for national greenhouse gas inventories, volume 4—agriculture, forestry and other land use. Prepared by the National Greenhouse Gas Inventories Programme. IGES, JapanGoogle Scholar
- Lindfors LG, Christiansen K, Hoffman L, Virtanen Y, Jun-tilla V, Hanssen O-J, Rønning A, Ekvall T, Finnveden G (1995): Nordic guidelines for life cycle assessment. Nordic Council of Ministers, Copenhagen, Denmark, Nord 1995:20Google Scholar
- Myhre G, Shindell D, Bréon FM, Collins W, Fuglestvedt J, Huang J, Koch D, Lamarque JF, Lee D, Mendoza B, Nakajima T, Robock A, Stephens G, Takemura T, Zhang H (2013) Anthropogenic and natural radiative forcing. In: Stocker TF, Qin D, Plattner GK, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: the physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USAGoogle Scholar
- Nature (2014) The composition of a bacterial cell. http://www.nature.com/scitable/content/the-composition-of-a-bacterial-cell-14705043 (accessed26 February 2016)
- Qasim SR (1999) Wastewater treatment plants: planning, design, and operation. CRC PressGoogle Scholar
- Rosenbaum RK, Bachmann TM, Gold LS, Huijbregts MAJ, Jolliet O, Juraske R, Köhler A, Larsen HF, MacLeod M, Margni M, McKone TE, Payet J, Schuhmacher M, van de Meent D, Hauschild MZ (2008) USEtox—the UNEPSETAC toxicity model: recommended characterisation factors for human toxicity and freshwater ecotoxicity in life cycle impact assessment. Int J Life Cycle Assess 13(7):532–546CrossRefGoogle Scholar
- Tchobanoglous G, Burton FL (eds) (1991) Wastewater engineering. Treatment disposal reuse, Metcalf & Eddy, Inc. McGraw-Hill, New YorkGoogle Scholar
- The Engineering Toolbox (2015) Fuels—higher calorific values. http://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html (accessed 3 August 2015)
- Van Haandel AC, Van der Lubbe JGM (2007) Handbook biological wastewater treatment. Design and optimisation of activated sludge systems. Quist Publishing, Lidschendam, The NetherlandsGoogle Scholar
- Weidema BP, Bauer C, Hischier R, Mutel C, Nemecek T, Reinhard J, Vadenbo CO, Wernet G (2013) Overview and methodology. Data quality guideline for the ecoinvent database version 3 Ecoinvent Report 1(v3). St. Gallen: The ecoinvent CentreGoogle Scholar