Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment Plant

Wastewater treatment plants (WWTPs) have been identified as important point sources of micropollutants and microplastics into the environment. Existing fourth cleaning steps are designed to remove dissolved micropollutants, however do not target dispersed solids such as microplastics. Therefore, the...

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Main Authors: Michael Toni Sturm, Erika Myers, Dennis Schober, Anika Korzin, Clara Thege, Katrin Schuhen
Format: Article
Language:English
Published: MDPI AG 2023-03-01
Series:Water
Subjects:
Online Access:https://www.mdpi.com/2073-4441/15/6/1164
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author Michael Toni Sturm
Erika Myers
Dennis Schober
Anika Korzin
Clara Thege
Katrin Schuhen
author_facet Michael Toni Sturm
Erika Myers
Dennis Schober
Anika Korzin
Clara Thege
Katrin Schuhen
author_sort Michael Toni Sturm
collection DOAJ
description Wastewater treatment plants (WWTPs) have been identified as important point sources of micropollutants and microplastics into the environment. Existing fourth cleaning steps are designed to remove dissolved micropollutants, however do not target dispersed solids such as microplastics. Therefore, the ability of an Advanced Oxidation Process (AOP) and Granular Activated Carbon (GAC) in parallel and serial connection to remove microplastics was investigated and determined. The pilot plants were operated at the municipal WWTP Landau, Germany, a three-step biological waste treatment plant with a capacity of 80,000 population equivalents. A Nile red-based detection method was applied to quantify microplastics. Neither method showed a significant removal of microplastics. To achieve a simultaneous removal of microplastics and dissolved micropollutants, a pilot plant using organosilanes for microplastics’ removal was connected in series with the GAC. When added to the water, the organosilanes attach to the microplastics and collect them in agglomerates by chemically binding them in a water-induced sol–gel process. The pilot plant for microplastics’ removal was operated with a flow rate of 12 m<sup>3</sup>/h and a retention time of 10 min; the GAC with 2 m<sup>3</sup>/h and a retention time of 1 h. An average reduction in micropollutants by 86.2 ± 2.0% and a reduction in microplastics by 60.9 ± 27.5% was reached. Thus, there is an effective reduction in micropollutants and a significant reduction in microplastics. Further optimizations of the pilot plant are expected to result in a more stable and higher removal performance.
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spelling doaj.art-ada46ac30244440f85c85cf6dc2bf7652023-11-17T14:27:22ZengMDPI AGWater2073-44412023-03-01156116410.3390/w15061164Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment PlantMichael Toni Sturm0Erika Myers1Dennis Schober2Anika Korzin3Clara Thege4Katrin Schuhen5Wasser 3.0 gGmbH, Neufeldstr. 17a–19a, 76187 Karlsruhe, GermanyWasser 3.0 gGmbH, Neufeldstr. 17a–19a, 76187 Karlsruhe, GermanyWasser 3.0 gGmbH, Neufeldstr. 17a–19a, 76187 Karlsruhe, GermanyWasser 3.0 gGmbH, Neufeldstr. 17a–19a, 76187 Karlsruhe, GermanyVan Remmen UV Technology, Hooglandweg 3a, 8131 TE Wijhe, The NetherlandsWasser 3.0 gGmbH, Neufeldstr. 17a–19a, 76187 Karlsruhe, GermanyWastewater treatment plants (WWTPs) have been identified as important point sources of micropollutants and microplastics into the environment. Existing fourth cleaning steps are designed to remove dissolved micropollutants, however do not target dispersed solids such as microplastics. Therefore, the ability of an Advanced Oxidation Process (AOP) and Granular Activated Carbon (GAC) in parallel and serial connection to remove microplastics was investigated and determined. The pilot plants were operated at the municipal WWTP Landau, Germany, a three-step biological waste treatment plant with a capacity of 80,000 population equivalents. A Nile red-based detection method was applied to quantify microplastics. Neither method showed a significant removal of microplastics. To achieve a simultaneous removal of microplastics and dissolved micropollutants, a pilot plant using organosilanes for microplastics’ removal was connected in series with the GAC. When added to the water, the organosilanes attach to the microplastics and collect them in agglomerates by chemically binding them in a water-induced sol–gel process. The pilot plant for microplastics’ removal was operated with a flow rate of 12 m<sup>3</sup>/h and a retention time of 10 min; the GAC with 2 m<sup>3</sup>/h and a retention time of 1 h. An average reduction in micropollutants by 86.2 ± 2.0% and a reduction in microplastics by 60.9 ± 27.5% was reached. Thus, there is an effective reduction in micropollutants and a significant reduction in microplastics. Further optimizations of the pilot plant are expected to result in a more stable and higher removal performance.https://www.mdpi.com/2073-4441/15/6/1164microplasticsmicropollutantswastewater treatment plantmicroplastics removalNile redadvanced oxidation process
spellingShingle Michael Toni Sturm
Erika Myers
Dennis Schober
Anika Korzin
Clara Thege
Katrin Schuhen
Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment Plant
Water
microplastics
micropollutants
wastewater treatment plant
microplastics removal
Nile red
advanced oxidation process
title Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment Plant
title_full Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment Plant
title_fullStr Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment Plant
title_full_unstemmed Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment Plant
title_short Comparison of AOP, GAC, and Novel Organosilane-Based Process for the Removal of Microplastics at a Municipal Wastewater Treatment Plant
title_sort comparison of aop gac and novel organosilane based process for the removal of microplastics at a municipal wastewater treatment plant
topic microplastics
micropollutants
wastewater treatment plant
microplastics removal
Nile red
advanced oxidation process
url https://www.mdpi.com/2073-4441/15/6/1164
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