Wastewater treatment plants as pathways of microlitter to the aquatic environment

Julia Talvitie

Wastewater treatment plants as pathways of microlitter to the aquatic environment

Julkaisun otsikon käännös: Jätevedenpuhdistamot mikroroskan kulkureittinä vesistöihin

Julia Talvitie

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Mikroroskaksi kutsutaan yleisesti alle 5 mm:n kokoista roskaa. Mikroroskien ja erityisesti mikromuovien ekologiseen merkitykseen on alettu kiinnittää erityistä huomiota viimeisen vuosikymmenen aikana. Mikroroskia päätyy ympäristöön useista eri lähteistä kuten liikenteestä, vaatteiden pesusta ja kosmetiikasta ja erityisesti jätevedenpuhdistamoita on epäilty yhdeksi merkittävimmistä mikroroskien kauttakulkureiteistä vesistöihin. Tässä työssä tutkittiin mikroroskien kulkeutumista ja poistumista perinteisen aktiivilietemenetelmään perustuvan jätevedenpuhdistusprosessin sekä erilaisten jälkikäsittelyiden aikana. Lisäksi tutkittiin jätevedenpuhdistamoiden vesistöihin aiheuttamaa mikroroskakuormitusta Itämeren sinisimpukoiden avulla. Tutkimuksessa verrattiin sinisimpukoista löydettävien mikroroskien määrää jätevesiä vastaanottavan ja verrokkialueen välillä. Tutkimuksissa havaittiin, että perinteinen jätevedenpuhdistus esikäsittelyineen ja jälkiselkeytyksineen poistaa tehokkaasti (> 99%) puhdistamolle tulevan mikroroskat. Suurin osa mikroroskista (~ 98%) poistui jo esikäsittelyn aikana ja aktiivilieteprosessi vähensi edelleen (~ 88%) mikroroskien määrää esikäsitellystä jätevedestä. Suurin osa mikroroskista pidättyi jätevedenpuhdistusprosessin aikana lietteeseen. Noin 20% lietteeseen pidättyvästä mikroroskasta päätyi kuitenkin takaisin prosessiin lietteen kuivauksessa syntyvän rejektiveden mukana. Perinteisesti käsitellystä jätevedestä voitiin edelleen poistaa mikroroskia erilaisten jälkikäsittelyiden avulla. Membraanisuodatustekniikkaan perustuva membraanibioreaktori (engl. membrane bioreactor, MBR) poisti lähes kaikki mikroroskat (99.9 %) esikäsitellystä jätevedestä. Myös jälkiselkeytyksen jälkeistä jätevettä käsittelevät tertiäärikäsittelyt kuten hiekkasuodatin, flotaatio ja kiekkosuodatin poistivat tehokkaasti mikroroskaa. Ainoastaan biologisella denitrifikaatiosuodattimella ei havaittu olevan vaikutusta mikroroskien määrään jätevedessä. Jätevedenpuhdistamot voivat olla merkittävä mikroroska- ja mikromuovikuormittaja, kun ottaa huomioon, että käsiteltyä jätevettä johdetaan jatkuvasti suuria määriä vesistöihin. Arviolta noin 480 miljardia mikromuovia päätyy Suomessa jätevedenpuhdistamoilta vesistöön. Toisaalta jätevedenpuhdistamot voivat tarjota ratkaisun mikromuovikuormituksen vähentämiseen. Itämeren sinisimpukoissa havaittiin korkeampia mikroroskamääriä jätevesiä vastaanottavalla merialueella kuin verrokkialueella. Havaitut korkeammat mikroroskamäärät saattavat johtua jätevedenpuhdistamoiden kuormittavasta vaikutuksesta. Muiden mahdollisten mikroroskan lähteiden ja reittien vaikutusta tuloksiin ei kuitenkaan pystytty sulkemaan tutkimuksessa pois.

Julkaisun otsikon käännös	Jätevedenpuhdistamot mikroroskan kulkureittinä vesistöihin
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Vahala, Riku, Vastuuprofessori Mikola, Anna, Ohjaaja Setälä, Outi, Ohjaaja, Ulkoinen henkilö
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-7979-0
Sähköinen ISBN	978-952-60-7980-6
Tila	Julkaistu - 2018
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

mikroroskat
mikromuovit
yhdyskuntajätevedet
jätevedenpuhdistamot
vesiympäristö
sinisimpukat

YK:n kestävän kehityksen tavoitteet

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http://urn.fi/URN:ISBN:978-952-60-7980-6Lisenssi: Määrittelemätön

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@phdthesis{b7706d03103c4c558aa1a93b9963206f,

title = "Wastewater treatment plants as pathways of microlitter to the aquatic environment",

abstract = "Microlitter and its synthetic sub-type microplastics, defined as anthropogenic particles less than 5 mm in size, are an ever-increasing form of marine litter that has received considerable attention over the past decades. Among the numerous possible sources and pathways that allow this microlitter to enter aquatic environments, wastewater treatment plants (WWTPs) have been suggested as one of the more significant pathways. This thesis examines the step-wise removal of microlitter during the purification process within conventional WWTPs utilizing conventional activated sludge processes. In addition, the removal of microplastics from wastewater effluents using five different advanced final-stage treatment technologies was investigated and the microplastic discharge from existing Finnish WWTPs into the aquatic environments was assessed. To further evaluate the environmental risk that microlitter may pose to aquatic food webs, their ingestion by Baltic blue mussels (Mytilus trossulus) was studied at a wastewater receiving area in the Gulf of Finland in the Northern Baltic Sea. These results show that conventional wastewater treatment using primary and secondary treatments can efficiently remove (> 99 %) microlitter arriving at the WWTP in influent. Most (98%) of the microlitter was removed during primary treatment. The activated sludge process further decreased (~ 88%) the microlitter concentration. During the wastewater treatment, most of the microlitter (> 99.5 %) was retained in the raw and excess sludge. However, part (~ 20 %) of the retained microlitter was recycled back to the treatment process along with the reject water. The removal of microplastics can be further enhanced by advanced final-stage wastewater treatment technologies. Membrane bioreactor removed an additional 99.9% of microplastics during treatment. Sand filtration removed 97%, dissolved air flotation removed 95 %, and disc filtration removed 40 – 98.5% of the MPs. Biologically active filtration did not have any impact on the microplastic concentration. According to our estimations, Finnish WWTPs annually discharge ~ 480 billion microplastic particles into aquatic environments. As vast volumes of wastewaters are constantly discharged into the aquatic environments, the role of WWTPs as pathways may be significant. However, to further evaluate the relative importance of the role of WWTPs as pathway for microplastics, information on other pathways are also needed. The results from the wastewater receiving environment indicate that the WWTPs may influence the microlitter and microplastics abundance and composition detected in biota. Blue mussels collected from the wastewater receiving area had higher microlitter content than those from the reference site.",

keywords = "microlitter, microplastics, municipal wastewaters, WWTPs, aquatic environment, blue mussels, mikroroskat, mikromuovit, yhdyskuntaj{\"a}tevedet, j{\"a}tevedenpuhdistamot, vesiymp{\"a}rist{\"o}, sinisimpukat, microlitter, microplastics, municipal wastewaters, WWTPs, aquatic environment, blue mussels",

author = "Julia Talvitie",

year = "2018",

language = "English",

isbn = "978-952-60-7979-0",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "86",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - Wastewater treatment plants as pathways of microlitter to the aquatic environment

AU - Talvitie, Julia

PY - 2018

Y1 - 2018

N2 - Microlitter and its synthetic sub-type microplastics, defined as anthropogenic particles less than 5 mm in size, are an ever-increasing form of marine litter that has received considerable attention over the past decades. Among the numerous possible sources and pathways that allow this microlitter to enter aquatic environments, wastewater treatment plants (WWTPs) have been suggested as one of the more significant pathways. This thesis examines the step-wise removal of microlitter during the purification process within conventional WWTPs utilizing conventional activated sludge processes. In addition, the removal of microplastics from wastewater effluents using five different advanced final-stage treatment technologies was investigated and the microplastic discharge from existing Finnish WWTPs into the aquatic environments was assessed. To further evaluate the environmental risk that microlitter may pose to aquatic food webs, their ingestion by Baltic blue mussels (Mytilus trossulus) was studied at a wastewater receiving area in the Gulf of Finland in the Northern Baltic Sea. These results show that conventional wastewater treatment using primary and secondary treatments can efficiently remove (> 99 %) microlitter arriving at the WWTP in influent. Most (98%) of the microlitter was removed during primary treatment. The activated sludge process further decreased (~ 88%) the microlitter concentration. During the wastewater treatment, most of the microlitter (> 99.5 %) was retained in the raw and excess sludge. However, part (~ 20 %) of the retained microlitter was recycled back to the treatment process along with the reject water. The removal of microplastics can be further enhanced by advanced final-stage wastewater treatment technologies. Membrane bioreactor removed an additional 99.9% of microplastics during treatment. Sand filtration removed 97%, dissolved air flotation removed 95 %, and disc filtration removed 40 – 98.5% of the MPs. Biologically active filtration did not have any impact on the microplastic concentration. According to our estimations, Finnish WWTPs annually discharge ~ 480 billion microplastic particles into aquatic environments. As vast volumes of wastewaters are constantly discharged into the aquatic environments, the role of WWTPs as pathways may be significant. However, to further evaluate the relative importance of the role of WWTPs as pathway for microplastics, information on other pathways are also needed. The results from the wastewater receiving environment indicate that the WWTPs may influence the microlitter and microplastics abundance and composition detected in biota. Blue mussels collected from the wastewater receiving area had higher microlitter content than those from the reference site.

AB - Microlitter and its synthetic sub-type microplastics, defined as anthropogenic particles less than 5 mm in size, are an ever-increasing form of marine litter that has received considerable attention over the past decades. Among the numerous possible sources and pathways that allow this microlitter to enter aquatic environments, wastewater treatment plants (WWTPs) have been suggested as one of the more significant pathways. This thesis examines the step-wise removal of microlitter during the purification process within conventional WWTPs utilizing conventional activated sludge processes. In addition, the removal of microplastics from wastewater effluents using five different advanced final-stage treatment technologies was investigated and the microplastic discharge from existing Finnish WWTPs into the aquatic environments was assessed. To further evaluate the environmental risk that microlitter may pose to aquatic food webs, their ingestion by Baltic blue mussels (Mytilus trossulus) was studied at a wastewater receiving area in the Gulf of Finland in the Northern Baltic Sea. These results show that conventional wastewater treatment using primary and secondary treatments can efficiently remove (> 99 %) microlitter arriving at the WWTP in influent. Most (98%) of the microlitter was removed during primary treatment. The activated sludge process further decreased (~ 88%) the microlitter concentration. During the wastewater treatment, most of the microlitter (> 99.5 %) was retained in the raw and excess sludge. However, part (~ 20 %) of the retained microlitter was recycled back to the treatment process along with the reject water. The removal of microplastics can be further enhanced by advanced final-stage wastewater treatment technologies. Membrane bioreactor removed an additional 99.9% of microplastics during treatment. Sand filtration removed 97%, dissolved air flotation removed 95 %, and disc filtration removed 40 – 98.5% of the MPs. Biologically active filtration did not have any impact on the microplastic concentration. According to our estimations, Finnish WWTPs annually discharge ~ 480 billion microplastic particles into aquatic environments. As vast volumes of wastewaters are constantly discharged into the aquatic environments, the role of WWTPs as pathways may be significant. However, to further evaluate the relative importance of the role of WWTPs as pathway for microplastics, information on other pathways are also needed. The results from the wastewater receiving environment indicate that the WWTPs may influence the microlitter and microplastics abundance and composition detected in biota. Blue mussels collected from the wastewater receiving area had higher microlitter content than those from the reference site.

KW - microlitter

KW - microplastics

KW - municipal wastewaters

KW - WWTPs

KW - aquatic environment

KW - blue mussels

KW - mikroroskat

KW - mikromuovit

KW - yhdyskuntajätevedet

KW - jätevedenpuhdistamot

KW - vesiympäristö

KW - sinisimpukat

KW - microlitter

KW - microplastics

KW - municipal wastewaters

KW - WWTPs

KW - aquatic environment

KW - blue mussels

M3 - Doctoral Thesis

SN - 978-952-60-7979-0

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Wastewater treatment plants as pathways of microlitter to the aquatic environment

Abstrakti

Tutkimusalat

YK:n kestävän kehityksen tavoitteet

Pääsy asiakirjaan

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