Degradation of PLA in Sewage Sludge and Methods of its Determination

abstract

English

Because pollution by plastics was declared as one of the most critical environmental problem of our time, to mitigate the environmental impact, plastics are slowly being replaced by bioplastics in many applications. Bioplastics are considered to by polymeric materials that comes from renewable sources, are recyclable and/or biodegradable. However, the biodegradation of bioplastics is largely dependent on both the material itself and the environment in which the biodegradation takes place and therefore complete degradation often occurs only in industrial composts. In the environment only partial degradation and/or fragmentation of bioplasts into micro and nanoplastics occuresaster than is common with conventional plastics. In the case of microplastics (MPs) contamination, wastewater treatment plants (WWTPs) represent the link between the natural and anthropogenic water cycle. WWTPs are considered to be MPs receptors from domestic and industrial wastewater. As the technological line of wastewater treatment was not adapted for treatment of MPs from wastewater, WWTPs were identified as a potential main source of MPs in aquatic environment. In the anthropogenic water cycle, MPs are found mainly in wastewater and inflows and outflowes of WWTPs. PLA is a biodegradable polymer that is increasingly found in wastewater in the form of MPs. As there is still no information about what happens to PLA when it goes through the whole process of wastewater treatment, the aim of our work is to determine whether PLA undergoes complete or only partial decomposition and develop reproducible methods of PLA analysis in complex matrices such is sewage sludge. To study PLA in sludge, we use WWTP in laboratory scale, with which we simulate the conditions of WWTP. The amount of PLA is then determined in the dried sludge by pyrolytic method, i.e. evolved gas analysis (EGA). The fact that the EGA can be used for determination of PLA has already been demonstrated by an previous experiment in which we proceeded similarly to that reported by David et al. The dried sludge (matrix) was spiked with PLA to create concentrations in range of 0,1% - 5,0%. By analyzing these samples, the characteristic molecular weights m/z were determined for PLA, which can be used for both qualitative and quantitative analysis. This work will provide the necessary information on the biodegradation of PLA in sewage sludge, which is needed as PLA gradually replaces conventional plastics in many industries. It can be assumed that their widespread use over time will cause an increased concentration of PLA microplastics (microbioplastics) in the inflow to the WWTP.

PLA, WWTP, microplastics

ROMÁNEKOVÁ, I.; KUČERÍK, J.

30. 11. 2021

serbian chemical society

belgrade

978-86-7132-078-8

Book of abstracts/EMEC21

98

98

150