Microplastics and microfibers in the sludge of a municipal wastewater treatment plant

The presence of microplastics and synthetic microfibers in the environment is increasing, causing an accumulation in the food chain because their ingestion by different organisms in the ecological community. This paper deals with the importance of wastewater treatment plants (WWTPs) as a source of microplastics and microfibers from the sludge to the environment. These micropollutants have been monitored in an urban WWTP during 2015, after being separated from the sludge. Micropollutants were extracted by flotation, using a concentrated solution of sodium chloride and several stainless steel sieves. After an initial screening performed with a trinocular microscope, the samples were analyzed by Fourier transform infrared spectrometry and a differential scanning calorimeter, this last technique only for the identified subsamples. Significant matches with databases could be observed, identifying different compounds such as polypropylene, Nylon , transparent thermoplastic polyamides, norbornene, and ethyl acrylate, among others. These microplastics and microfibers could be transported with organic matter on fertilizers, being used as compost in the field crops of Campo de Cartagena.