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Bæredygtig og decentral rensning af vaskerispildevand, herunder fjernelse af mikroplast

Publikation: Bog/antologi/afhandling/rapportRapport

  • Michelle Lison Rebsdorf, Teknologisk Institut - Teknologisk Partnerskab
  • ,
  • Morten Bormann Nielsen, Teknologisk Institut - Teknologisk Partnerskab
  • ,
  • Dennis Smidt, Berendsen Textil Service A/S
  • ,
  • Orla U. Jensen, Dankalk A/S
  • ,
  • Jan Hansen, AL-2 Teknik A/S
  • ,
  • Peder Hvid Maribo
There is a great focus on the release of microplastics to our aquatic environments in relation to stormwater and wastewater discharges. Some industries e.g. laundry facilities, such as Berendsen mat laundries, are expected to produce wastewater with a high content of micro-plastics e.g. fibers from mats and clothing as well as plastic and rubber particles from the wiping of shoes. This project has focused on the development of a decentralized wastewater treatment unit based on the combination of chemical precipitation, flocculation and belt filter technology for the removal of microplastics and organic matter in laundry wastewater. Also, the project aimed to develop a valid analysis method for qualifying and characterizing of microplastics - with special focus on microfibers - and micro rubber found in laundry wastewater. 2.1 Method for analyzing microplastic and micro rubber The development of the analysis method was based on an existing method using Raman Spectroscopy for microplastic characterization. The analysis method applied has been de-veloped and optimized by Danish Technological Institute in several R&D projects during the past five years and was further improved in this specific project. In order to fulfill the re-quirements for the method, the project has focused on improving the sample purification and preparation before the measurement as well as fine-tuning the analysis technique through the developing and application of several algorithms. The purpose of the purification procedure is to remove organic and inorganic residual mate-rial from the sample while leaving particles and fibers of plastic and rubber intact. During this project, the purification process was optimized in order to shorten the duration of the whole procedure. Initially, the procedure took a total of 9 days, but was reduced to 6 days, without compromising the removal of organic material. Furthermore, different oxidizing agents were tested on rubber and four different types of plastics to ensure that the chemical treatment applied, did not degrade microplastics and micro rubber in the samples. However, it was not possible to find one suitable oxidant for the purification of both microplastics and micro rubber. Therefore, two parallel purification procedures were developed, with potassi-um hydroxide as the chemical oxidant for the purification of micro rubber and hydrogen peroxide as a chemical oxidant for the purification of microplastics. The project succeeded in developing a significantly improved analysis method based on Raman spectroscopy for measuring microplastics and micro rubber. The method enables the characterization and mass determination of a large number of particles - typically be-tween 10,000 and 30,000 particles in one sample - as small as 15-20 µm in diameter. The implementation of several developed algorithms enables the method to identify all the common types of plastics as well as tire rubber and at the same time discard other extrane-ous materials such as sand and asphalt. In addition, the developed analysis method can translate these measurements into an estimate of the total mass of different plastic types and rubber in a given sample. 2.2 The development of a decentralized wastewater treatment unit The development of a decentralized wastewater treatment unit for removal of microplastics and organic matter in laundry wastewater was based on AL-2 Teknik's separation technolo-gy. The main success criteria for the developed wastewater treatment unit was that it should be able to retain 50 % of the organic matter and 80 % of microplastic particles and fibers > 10 µm in laundry wastewater. Extensive laboratory and pilot tests have been carried out in the project to further develop AL-2 Teknik's separation technology to meet these require-ments. Laboratory tests have been performed to identify the most suitable chemical agents for chemical precipitation and subsequent flocculation with respect to the removal of both or-ganic matter and microplastics using a belt filter. Afterwards, a pilot plant based on the sepa-ration technology was developed and pilot tests were carried out at Berendsen mat laundry facilities in Karup, Central Jutland. Test results of a spiking test showed that 99.99 % of ca. 1 million microplastic particles (100 µm in diameter) were removed in the separation plant. Furthermore, the pilot plant was able to remove 98% of the microplastic and micro rubber (particle size > 10 µm) in the laundry wastewater. In addition, 66-82 % of the organic material in the wastewater was retained.
OriginalsprogDansk
UdgivelsesstedKøbenhavn
ForlagMiljøstyrelsen
Antal sider63
ISBN (Trykt)978-87-7038-243-4
StatusUdgivet - 2020

    Forskningsområder

  • Mikroplast, båndfilter, spildevand

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