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Μελέτη της χρονικής διακύμανσης των μικροπλαστικών στην έξοδο της ΕΕΛ Χανίων (Εγκατάσταση Επεξεργασίας Λυμάτων Χανίων)

Gavalakis Georgios

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Year 2022
Type of Item Diploma Work
Bibliographic Citation Γεώργιος Γαβαλάκης, "Μελέτη της χρονικής διακύμανσης των μικροπλαστικών στην έξοδο της ΕΕΛ Χανίων (Εγκατάσταση Επεξεργασίας Λυμάτων Χανίων)", Διπλωματική Εργασία, Σχολή Χημικών Μηχανικών και Μηχανικών Περιβάλλοντος, Πολυτεχνείο Κρήτης, Χανιά, Ελλάς, 2022
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Plastic products have been a very important pillar of our society, as they have greatly contributed to its development. Their misuse, however, has turned them into a huge ecological threat, as they have invaded ecosystems. As a results, their high concentration in the environment raises serious questions about the effects they may have, due to their toxicity and ability to absorb heavy metals and organic pollutants to their surface, and by constituting a substrate for the development of pathogenic microorganisms. Microplastic particles (Mps) are produced either by the wear of larger plastics or they are components of certain products and have a size ranging from 1 μm to 5 mm. Their form is differentiated (fragments, fibers) and are separated depending on their source of origin (primary, secondary). Wastewater treatment plants (WWTPs) are an important source of Mps for the environment, as they are collectors of urban and industrial waste with a high concentration of Mps.The present dissertation aims at the detection of Mps in the urban wastewater of the city of Chania and the study of time variation(winter-summer) of the concentration of MPs the exit of the wastewater treatment plant (WWTP). The time variation was chosen in order to determine whether the high tourist traffic received by the city of Chania during springtime, as well as the change of weather conditions can affect the price of the concentration of Mps in the sewage.For the implementation of the study, eighteen samples were taken over a period of six months and a total of 830 liters a sample was collected. The winter season included January, February, and March while the spring season included July, August and September. During March July, August and September, that the sampling took place, the global health crisis of covid-19 pandemic had broken. Moreover, due to the restrictions imposed, the number of visitors during the summer period fluctuated in smaller numbers compared to previous years. Fragments and fibers ranging from 20 μm to 500 μm were defined as Mps and identified by the method of stereomicroscopic image analysis. The Mps were separated into four groups according to their size (20 – 80 μm, 80-200 μm, 200-500 μm, >500 μm) and based on the data collected, the following were calculated:1. The average daily concentration of Mps (fragments, fibers) in wastewater.2. The price of the concentration of Mps (fragments, fibers) in winter and spring.3. The price of the concentration of Mps (fragments, fibers) for every month.4. The daily supply of Mps (fragments, fibers) in the area of Chania based on the price of the concentration and the daily supply of the treated wastewater which was rejected at the facility.The average daily concentration of Mps in the wastewater was calculated at 11.5 ± 7.99 (MPs/L) while the average daily flow of MPs wasted in the sea was calculated at 221 x106 (MPs/Day). The results of the process of concentration of the two periods, showed that the concentration of MPs in the wastewater increased considerably during the summer period 16.27 ± 5.6 (MPs/L) in comparison to the respective price of the winter season 6.4 ± 1.4 (MPs/L). The monthly concentration curve showed a constant increase in its price, reaching the maximum price in September.The MPs consisted of 85% fragments and 15% synthetic fibers. The change of concentration of fragments between the two periods showed a great increase of the daily concentration in the Spring period 15.3 ± 8.8 (Fragment/L), in the relation to the respective price of the Winter period 4.7 ± 1.05 (Fragment/L). However, the increase which was recorded in fibers, in the spring season range in smaller margins, with the concentration in summer being calculated at 1.94 ± 0.96 (Fiber/L) and in winter at 1.7 ± 1.1 (Fiber/L) on a daily basis.

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