Environmental Engineering (Wastewater treatment) Core Course Laboratory of Environmental Engineering & Planning Department of Civil Engineering Aristotle University of Thessaloniki

Environmental Engineering Course description Introduction to urban wastewater treatment. Introduction to environmental biochemistry and biotechnology. Physical, chemical and biological characteristics of urban sewage. Mechanical treatment (screens, grit chambers, sedimentation basins). Biological treatment (activated sludge bioreactors, trickling filters, rotating disc contactors). Natural systems for sewage treatment. Chemical treatment. Disinfection and disposal. Sewage sludge treatment (thickening, stabilization and dewatering).

Teaching Lectures (5 hours/week) Labs (3 hours/semester) Exercise (Dimensioning a WWTP) Visit to a WWTP Interactive environment (Blackboard) – Literature: – Metcalf & Eddy, Inc., “Wastewater Engineering, Treatment and Reuse” 4 th edition, Revised by George Tchobanoglous, Franklin L. Burton, H. Daviv Stensel. – Efthymios Darakas,“Environmental Engineering” A.U.Th. 3 Environmental Engineering

Biological Treatment Suspended Biomass Treatment (Activated Sludge) Attached Growth Treatment (Trickling filters, RBC) Attached Growth Treatment (Trickling filters, RBC)

Influent Primary clarifier Bar Grit chamber Disinfection Effluent Secondary clarifier Bioreactor Ο2Ο2 Sludge return Thickening Anaerobic digestion (Post thickening) Dewatering Dewatered sludge Biogas Supernatant liquor Sludge Mechanical Treatment Biological Treatment Sludge treatment Advanced treatment P.S. 5 Environmental Engineering WWTP (Typical diagram, Activated Sludge)

Environmental Engineering

Mechanical Treatment 7 Bars Influent Effluent Grit chamber Sludge Sedimentation tank Screenings Sand

Biological Treatment – Activated Sludge 8 Suspended biomass Bioreactor Secondary clarifier

Wastewater treatment - Aeration techniques 9

10 Nitrification - Denitrification

11 1 1

12 Anoxic zone Denitrification 2 2 Nitrification - Denitrification

13 Influent ΝΗ 4 + C Ο2Ο2 Effluent N2N2 N2N2 Secondary clarifier Recirculation Sludge N2N2 N2N2 3 3 Nitrification - Denitrification

Nitrification - Denitrification

Attached Growth Treatment 15

16 Pebbles or gravel Moving Bed Biofilm Reactor (MBBR) - Synthetic materials

17

Rotating Biological Contactors (RBC) 18

19 Sedimentation tanks

Sedimentation tanks - Clarifiers 20

Sedimentation tank 21

Tertiary treatment Membranes Adsorption (activated carbon) Ion exchange (resins)

Disinfection of wastewater (Chlorination) 23 Influent Effluent Disinfection tanks Cl 2

UV Disinfection channels 24

Ozone 25

Sludge treatment Drying and disposal Dewatering Conditioning Stabilization (aerobic – anaerobic) Thickening 26

Thickeners 27

28 Bioreactor Secondary sedimentation Primary sedimentation Stabilization tank (Aerobic) Thickener Supernatent liquid Sludge Excess sludgeRecirculation Dewatering Effluent Sludge stabilization (Aerobic) Ευθ. Νταρακάς

Anaerobic digestion of sewage sludge 29

30 Anaerobic digesters

Dewatering beds 31 Sludge 30 cm Sand 10 cm (0,2-0,6 mm) Sand 10 cm (7-15 mm) Gravel 20 cm (15-30 mm) Drainage

32 Dewatering (Solar energy) Dewatering (Solar energy)

33 Presses Filter presses

34 Decanters

35 Sewage sludge management