M
unicipal wastewater treatment facilities face
pressure to produce cleaner discharges while also
using less energy. This requires a new paradigm in
which wastes are converted into energy.
Associate Professor Lisa M. Colosi Peterson and
colleagues in the U.Va. Department of Civil and
Environmental Engineering have shown that integration
of wastewater treatment and large-scale algae-to-energy
systems delivers synergies compared to standalone
facilities. Subsequent life cycle assessments (LCAs)
have documented the environmental benefits of these
systems as pertaining to nutrient recycling.
Colosi Peterson’s group is investigating a previously
overlooked benefit: algae-mediated removal of
unregulated “emerging contaminants,” including
estrogens, pharmaceuticals, and personal care products
(e.g., sunscreen, detergents, etc). Early results are
extremely promising. Colosi Peterson and fellow
researchers have observed efficient removal of selected
contaminants under lab conditions.
Corresponding LCA results indicate that the algaebased system outperforms conventional tertiary
treatments, because it is the only option that creates more
en ergy than it consumes. Ongoing work will expand our
understanding of algae-mediated treatments; making a
case for voluntary removal of unregulated contaminants
via treatment that essentially pays for itself.
Large-scale algae cultivation could be
integrated into conventional municipal
wastewater treatment, as a means
to remove residual nutrients (e.g.,
nitrogen – N) and also unregulated
organic “emerging contaminants” (e.g.,
estradiol). The resulting algae biomass is
suitable for co-digestion with wastewater
biosolids, generating net energy output
that more than compensates for the addition of an algae cultivation pond downstream from
secondary treatment. Because the emerging are not currently regulated, it is appealing to
devise cost-effective technologies to remove them before discharge into receiving waters.
U.Va. ENGINEERING
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