EcoImpact 2.0

EcoImpact 2.0: Impacts of advanced wastewater treatments on tolerance of stream periphyton to micropollutants

The upgrade of about 100 Swiss wastewater treatment plants (WWTP) to specifically remove micropollutants (MP) offers a unique opportunity to assess the efficiency of MP removal technologies and consequent in-stream changes of aquatic organisms. In EcoImpact 1, clear biological responses related to MP exposure from WW effluents have been identified at different levels of biological organization, ranging from cells to organisms to communities. It was demonstrated that stream biofilms, also termed periphyton, downstream of WWTPs were more tolerant towards the discharged MPs than upstream. This Pollution Induced Community Tolerance (PICT) disappeared upon upgrading the WWTP for MP removal. These findings provide a first line of evidence on the relevance of using PICT and periphyton communities to assess the biological impact of MPs  from WW and their removal in the receiving waters.

Project goals and research questions:

EcoImpact 2.0 focuses on the previously observed development of periphyton tolerance as MP-related biological responses in the receiving waters. The ultimate goals are to examine how to use PICT for a comparative assessment of the biological effects of treatment technologies, and whether PICT could be established as a water quality assessment tool in practice.

We will experimentally address the following four research questions:

Q1. Can we observe PICT in periphyton growing in experimental flumes that are treated with WWTP effluents?

Q2. Is the observed PICT in periphyton downstream from WWTPs driven by MP exposure or by the release of tolerant microorganisms from the WWTP or a combination of both?

Q3. To which degree do different (combinations of) advanced WW treatment technologies affect tolerance development to MPs in periphyton?

Q4. What is the potential role of PICT for future monitoring to assess the biological effects of upgrading WWTPs?

Experimental approaches

Investigations with varying degrees of experimental control were carried out in the Maiandros flume system, consisting of 20 channels, in which periphyton was grown on glass plates. The flumes are located in the experimental hall at Eawag. We varied the chemical and biological composition of WW effluent by various combinations of WW treatment processes. We study the effect of these manipulations on the chemical and biological water quality, focusing on periphyton tolerance, structure and function as biological effect indicators. To be able to evaluate the role of PICT for future monitoring programs, field studies at sites undergoing WWTP upgrades accompany the flume experiments.

Project team

Project Management

Project leader: Christan Stamm

Dr. Christian Stamm Deputy Director Tel. +41 58 765 5565 Send Mail

Project team

Prof. Dr. Kristin Schirmer Group leader and deputy head of department Tel. +41 58 765 5266 Send Mail
Dr. Nele Schuwirth Head of Department and Group Leader (she/her) Tel. +41 58 765 5528 Send Mail
Simon Wullschleger Technician Tel. +41 58 765 5191 Send Mail

Louis Carles
former Eawag PostDoc
in EcoImpact 2

Publications

Extbase Variable Dump
array(3 items)
   publications => '30748,25790,23265' (17 chars)
   libraryUrl => '' (0 chars)
   layout => '0' (1 chars)
Extbase Variable Dump
array(3 items)
   0 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=30748, pid=124)
      originalId => protected30748 (integer)
      authors => protected'Lafuente, E.; Carles, L.; Walser, J. C.; Giulio, M.
         ; Wullschleger, S.; Stamm, C.; Räsänen, K.
' (135 chars) title => protected'Effects of anthropogenic stress on hosts and their microbiomes: treated wast
         ewater alters performance and gut microbiome of a key detritivore (<em>Asell
         us aquaticus</em>)
' (170 chars) journal => protected'Evolutionary Applications' (25 chars) year => protected2023 (integer) volume => protected16 (integer) issue => protected'4' (1 chars) startpage => protected'824' (3 chars) otherpage => protected'848' (3 chars) categories => protected'chemical pollution; environmental stress; freshwater ecosystems; host–micr
         obiome interactions; isopods
' (104 chars) description => protected'Human activity is a major driver of ecological and evolutionary change in wi
         ld populations and can have diverse effects on eukaryotic organisms as well
         as on environmental and host-associated microbial communities. Although host
         –microbiome interactions can be a major determinant of host fitness, few s
         tudies consider the joint responses of hosts and their microbiomes to anthro
         pogenic changes. In freshwater ecosystems, wastewater is a widespread anthro
         pogenic stressor that represents a multifarious environmental perturbation.
         Here, we experimentally tested the impact of treated wastewater on a keyston
         e host (the freshwater isopod Asellus aquaticus) and its gut microbiome. We
         used a semi-natural flume experiment, in combination with 16S rRNA amplicon
         sequencing, to assess how different concentrations (0%, 30%, and 80%) of non
         filtered wastewater (i.e. with chemical toxicants, nutrients, organic partic
         les, and microbes) versus ultrafiltered wastewater (i.e. only dissolved poll
         utants and nutrients) affected host survival, growth, and food consumption a
         s well as mid- and hindgut bacterial community composition and diversity. Ou
         r results show that while host survival was not affected by the treatments,
         host growth increased and host feeding rate decreased with nonfiltered waste
         water – potentially indicating that A. aquaticus fed on organic matter and
          microbes available in nonfiltered wastewater. Furthermore, even though the
         midgut microbiome (diversity and composition) was not affected by any of our
          treatments, nonfiltered wastewater influenced bacterial composition (but no
         t diversity) in the hindgut. Ultrafiltered wastewater, on the other hand, af
         fected both community composition and bacterial diversity in the hindgut, an
          effect that in our system differed between sexes. While the functional cons
         equences of microbiome changes and their sex specificity are yet to be teste
         d, our results indicate that different components of multifactorial stressor
         s (i.e. different consti...
' (2183 chars) serialnumber => protected'1752-4571' (9 chars) doi => protected'10.1111/eva.13540' (17 chars) uid => protected30748 (integer) _localizedUid => protected30748 (integer)modified _languageUid => protectedNULL _versionedUid => protected30748 (integer)modified pid => protected124 (integer)
1 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=25790, pid=124) originalId => protected25790 (integer) authors => protected'Carles,&nbsp;L.; Wullschleger,&nbsp;S.; Joss,&nbsp;A.; Eggen,&nbsp;R.&nbsp;I
         .&nbsp;L.; Schirmer,&nbsp;K.; Schuwirth,&nbsp;N.; Stamm,&nbsp;C.; Tlili,&nbs
         p;A.
' (156 chars) title => protected'Wastewater microorganisms impact microbial diversity and important ecologica
         l functions of stream periphyton
' (108 chars) journal => protected'Water Research' (14 chars) year => protected2022 (integer) volume => protected225 (integer) issue => protected'' (0 chars) startpage => protected'119119 (13 pp.)' (15 chars) otherpage => protected'' (0 chars) categories => protected'stream biofilm; prokaryotes; eukaryotes; DNA metabarcoding; micropollutants;
          pollution-induced community tolerance
' (114 chars) description => protected'Effluents of wastewater treatment plants can impact microbial communities in
          the receiving streams. However, little is known about the role of microorga
         nisms in wastewater as opposed to other wastewater constituents, such as nut
         rients and micropollutants. We aimed therefore at determining the impact of
         wastewater microorganisms on the microbial diversity and function of periphy
         ton, key microbial communities in streams. We used a flow-through channel sy
         stem to grow periphyton upon exposure to a mixture of stream water and unfil
         tered or ultra-filtered wastewater. Impacts were assessed on periphyton biom
         ass, activities and tolerance to micropollutants, as well as on microbial di
         versity. Our results showed that wastewater microorganisms colonized periphy
         ton and modified its community composition, resulting for instance in an inc
         reased abundance of Chloroflexi and a decreased abundance of diatoms and gre
         en algae. This led to shifts towards heterotrophy, as suggested by the chang
         es in nutrient stoichiometry and the increased mineralization potential of c
         arbon substrates. An increased tolerance towards micropollutants was only fo
         und for periphyton exposed to unfiltered wastewater but not to ultra-filtere
         d wastewater, suggesting that wastewater microorganisms were responsible for
          this increased tolerance. Overall, our results highlight the need to consid
         er the role of wastewater microorganisms when studying potential impacts of
         wastewater on the receiving water body.
' (1483 chars) serialnumber => protected'0043-1354' (9 chars) doi => protected'10.1016/j.watres.2022.119119' (28 chars) uid => protected25790 (integer) _localizedUid => protected25790 (integer)modified _languageUid => protectedNULL _versionedUid => protected25790 (integer)modified pid => protected124 (integer)
2 => Snowflake\Publications\Domain\Model\Publicationprototypepersistent entity (uid=23265, pid=124) originalId => protected23265 (integer) authors => protected'Carles,&nbsp;L.; Wullschleger,&nbsp;S.; Joss,&nbsp;A.; Eggen,&nbsp;R.&nbsp;I
         .&nbsp;L.; Schirmer,&nbsp;K.; Schuwirth,&nbsp;N.; Stamm,&nbsp;C.; Tlili,&nbs
         p;A.
' (156 chars) title => protected'Impact of wastewater on the microbial diversity of periphyton and its tolera
         nce to micropollutants in an engineered flow-through channel system
' (143 chars) journal => protected'Water Research' (14 chars) year => protected2021 (integer) volume => protected203 (integer) issue => protected'' (0 chars) startpage => protected'117486 (14 pp.)' (15 chars) otherpage => protected'' (0 chars) categories => protected'pollution-induced community tolerance; aquatic biofilm; passive sampler; org
         anic micropollutants; microbial diversity; 16S and 18S rRNA gene sequencing
' (151 chars) description => protected'Wastewater treatment plants (WWTPs) play an important role in retaining orga
         nic matter and nutrients but to a lesser extent micropollutants. Therefore,
         treated wastewater is recognized as a major source of multiple stressors, in
         cluding complex mixtures of micropollutants. These can potentially affect mi
         crobial communities in the receiving water bodies and the ecological functio
         ns they provide. In this study, we evaluated in flow-through channels the co
         nsequences of an exposure to a mixture of stream water and different percent
         ages of urban WWTP effluent, ranging from 0% to 80%, on the microbial divers
         ity and function of periphyton communities. Assuming that micropollutants ex
         ert a selective pressure for tolerant microorganisms within communities, we
         further examined the periphyton sensitivity to a micropollutant mixture extr
         acted from passive samplers that were immersed in the wastewater effluent. A
         s well, micropollutants in water and in periphyton were comprehensively quan
         tified. Our results show that micropollutants detected in periphyton differe
         d from those found in water, both in term of concentration and composition.
         Especially photosystem II inhibitors accumulated in periphyton more than oth
         er pesticides. Although effects of other substances cannot be excluded, this
          accumulation may have contributed to the observed higher tolerance of photo
         trophic communities to micropollutants upon exposure to 30% and 80% of waste
         water. On the contrary, no difference in tolerance was observed for heterotr
         ophic communities. Exposure to the gradient of wastewater led to structural
         differences in both prokaryotic and eukaryotic communities. For instance, th
         e relative abundance of cyanobacteria was higher with increasing percentage
         of wastewater effluent, whereas the opposite was observed for diatoms. Such
         results could indicate that differences in community structure do not necess
         arily lead to higher tolerance. This highlights the need to consider other w
         astewater constituents s...
' (2512 chars) serialnumber => protected'0043-1354' (9 chars) doi => protected'10.1016/j.watres.2021.117486' (28 chars) uid => protected23265 (integer) _localizedUid => protected23265 (integer)modified _languageUid => protectedNULL _versionedUid => protected23265 (integer)modified pid => protected124 (integer)
Lafuente, E.; Carles, L.; Walser, J. C.; Giulio, M.; Wullschleger, S.; Stamm, C.; Räsänen, K. (2023) Effects of anthropogenic stress on hosts and their microbiomes: treated wastewater alters performance and gut microbiome of a key detritivore (Asellus aquaticus), Evolutionary Applications, 16(4), 824-848, doi:10.1111/eva.13540, Institutional Repository
Carles, L.; Wullschleger, S.; Joss, A.; Eggen, R. I. L.; Schirmer, K.; Schuwirth, N.; Stamm, C.; Tlili, A. (2022) Wastewater microorganisms impact microbial diversity and important ecological functions of stream periphyton, Water Research, 225, 119119 (13 pp.), doi:10.1016/j.watres.2022.119119, Institutional Repository
Carles, L.; Wullschleger, S.; Joss, A.; Eggen, R. I. L.; Schirmer, K.; Schuwirth, N.; Stamm, C.; Tlili, A. (2021) Impact of wastewater on the microbial diversity of periphyton and its tolerance to micropollutants in an engineered flow-through channel system, Water Research, 203, 117486 (14 pp.), doi:10.1016/j.watres.2021.117486, Institutional Repository

Contact

Dr. Christian Stamm Deputy Director Tel. +41 58 765 5565 Send Mail

NEWS

EcotoxicoMicYR: First international webinar of young microbial ecotoxicology researchers
December 14, 2021 - Louis Carles, postdoctoral scientist in the Department of Environmental Toxicology, won the award for the best live presentation during the webinar “EcotoxicoMic for Young Researchers”. He presented his work conducted in the project EcoImpact 2.0 on the impact of wastewater on stream biofilms. Louis Carles is now invited to present his work at the EcotoxicoMic 2022 Conference (Montpellier, France, 15-18 November 2022).