Obrada otpadne vode autopraonice potopnom membranskom filtracijom

master's thesis

• Title (english): Submerged membrane filtration of car wash wasterwater
• Author: Eugen Ivanović
• Mentor: Slaven Dobrović (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom radu su dani rezultati ispitivanja praktične provedivosti membranske filtracije otpadne vode nastale pranjem automobila, prikupljene s dvije različite lokacije grada Zagreba. Filtriranje je provedeno potopnim mikrofiltracijskim membranskim elementom površine 5,6 m2 pri različitim radnim uvjetima. Za potrebe ispitivanja korišten je membranski pilot uređaj opremljen za nadzirani automatski rad s mogućnošću kontinuiranog mjerenja i zapisa protoka kroz membranu, tlaka na usisu crpke, visine stupca vode membranskog reaktora te temperaturu vode. Varirani radni uvjeti uključivali su iznos protoka kroz membranu, odnosno fluks, te koncentraciju suspendiranih tvari otpadne vode, dok je trajanje ciklusa pranja kao i režim protustrujnog pranja bio konstantan.
Mjerenja su se za danu kvalitetu vode provodila kroz nekoliko uzastopnih filtracijskih ciklusa pri odabranom protoku filtrirane vode. Analizom zapisa mjernih operativnih veličina opserviralo se radno stanje membrane u pogledu permeabilnosti za svaki ciklus te se zaključilo o pitanjima očuvanja permeabilnosti membrane, odnosno povoljnih radnih uvjeta u pogledu utroška energije za filtarcijski proces. Izabranim radnim uvjetima nastojala se osigurati uspješnost filtracijskog procesa uz nenarušene permeabilnosti membrane do koje može doći nakupljanjem suspendiranih čestica na mikrofiltracijskom membrani. Praćenje uspješnosti filtracijskog procesa provodilo se laboratorijski, mjerenjem suspendiranih čestica na standardnom staklenom filtru te turbidimetrijom.
Na temelju rezultata, potvrđeno je da se primjenom membranske filtracije omogućuje ponovno korištenje obrađene vode u procesu pranja automobila. Niski sadržaj suspendiranih tvari te rezidualni deterdženti ovakvu vodu čine vrlo primjerenom u operacijama predpranja i pranja vozila, dok bi se čista voda niskog saliniteta koristila samo za završno ispiranje vozila. U tom pogledu predložen je koncept unaprijeđenog sustava za prihvat i obradu otpadne vode autopraonica, s membranskom rekuperacijom vode od preko 50%. Ovakvo rješenje dio je kružnog gospodarenja vodom održivih društava jer čuva resurse, smanjuje opterećenje sustava odvodnje te pruža značajne uštede u poslovanju autopraonica.

Abstract (english)

This paper provides the test results of membrane filtration’s practical feasibility of wastewater, which was collected from washing cars, from two different locations in the city of Zagreb. Filtration was performed with 5.6 m2 submerged microfiltration membrane element under different operating conditions. Submerged membrane pilot test unit was equipped for controlled automatic operation with continuous monitoring of water flow, transmembrane pressure (TMP), height of the wastewater level in the tank and water temperature. Testing was conducted with variation of membrane flux (MF) and the concentration of suspended solids, while the duration of the washing cycle and backwash regime was kept constant.
Each group of testing cycles was performed in series for chosen water flux and the quality of wastewater. The analysis of monitored TMP and MF during the filtration cycle gave information about the membrane permeability and level of membrane clogging. The aim of the testing was to determine the filtration conditions for successful separation of suspended solids without significant deterioration of membrane functional characteristics due to the accumulation of suspended solids on the membrane. Efficiency of the filtration process was monitored in the laboratory through total suspended solids glass filtration method and by turbidimetry of the filtered water.
The results of the submerged membrane filtration testing confirmed that this treatment could allow the reuse of treated water in car wash units. Low concentrations of suspended solids and detergent residuals make filtered water suitable in pre-washing and washing processes while final rinsing of the vehicle requires clean, low salinity water. In that regard, improved car wash wastewater management, could save more than 50% of water by treatment and reuse suggested with this work. This solution saves resources, reduces the load to the municipal wastewater system, provides significant savings in car washing processes and therefore is part of the circular management of sustainable societies.

• Keywords: Membranska filtracija; potopni mikrofiltracijski membranski element; protustrujno pranje; fluks; transmembranski tlak; separacija suspendiranih tvari; ponovno korištenje obrađene vode
• Keywords (english): Membrane filtration; submerged microfiltration membrane; backwash; flux; transmembrane pressure; membrane clogging; separation of suspended solids; improved wastewater management; reuse of treated water
• Language: croatian
• URN:NBN: urn:nbn:hr:235:219764
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2023-07-16
• Created on: 2021-07-14 09:31:46