(124f) Sustainable Energy Bio-Sources, An Environmental Performance Approach: Life Cycle Assessment From WWTP to BESs

Sustainable
energy bio-sources, an environmental performance approach: life cycle
assessment from WWTP to BESs

G. Blejman¹, R.
Pacciani^1,2, S. Guri^1,2, and L.F. Vega^1,2

¹ MATGAS Research Center, Campus UAB, 08193 Bellaterra,
Barcelona, Spain

² Carburos Metálicos,
Air Products Group, C/ Aragón 
300, 08009 Barcelona, Spain

There is a huge impetus for developing new
technologies for the production of both energy and bioproducts
in a sustainable way. For example, Bio-Electrochemical Systems (BESs), such as Microbial
Fuel Cells (MFCs) and Microbial Electrolysis Cells (MECs) are novel
technologies which promise to replace energy intensive wastewater treatment
processes (WWTPs) by converting the organic waste fraction present in
wastewater into hydrogen or electricity. Their potential as sustainable
technologies for combined energy and biofuel
production is very high, considering the huge amount of sludge generated
(average 30 kg dry matter/inhabitant·year). Moreover,
defining the characteristics and the environmental burdens of the wastewater coming
into a WWTP plays a key role in understanding the possible applications of the
sludge for generating energy and hydrogen with MFCs and MECs, respectively.

In
this work we analyse the environmental impact of (i)
a Wastewater Treatment Plant and (ii) the production of Hydrogen and biogas from
the sludge generated in the WWTP itself.

Firstly
we assess the environmental impact of 1 m3 of water entering the Waste Water Treatment
(WWTP) process using Life Cycle Assessment methodology. We then identify the
environmental hot spots in the process chain, focusing on the most important environmental
burdens of a WWTP: energy use, main pollutants from personal care products,
heavy metals and final utilization of sludge as a bioproduct.

The
environmental impact is assessed with Simapro,
Version 7.2, with CML2000 method. The impact categories considered are: AP
(acidification potential, global, kg SO2 eq.), GWP100a (global warming
potential, kgCO2 eq.), EP (eutrophication potential,
global, kg PO₄ eq.), PHO (photochemical oxidation, kg formed ozone),
DAR (depletion of abiotic resources, kg antimony
eq.), ODP (ozone depletion potential, kg CFC-11 eq.), ETP (ecotoxicity
potential, kg 1,4-DCB eq.) as well as CED (Cumulative Energy
Demand). Bearing in mind that water reuse and reclamation is one of the main
issues of water sustainability, we add to the standard CML impact categories the
Freshwater Ecosystem Indicator, (direct effect on biodiversity of freshwater
ecosystem) and the Freshwater Depletion (FD), to properly estimate the impact
of the process in the water cycle.

This project is partially financed
by Carburos Metálicos and
the Spanish Government, CDTI, in the CENIT BIOSOS, belonging to the Program Ingenio 2010.