1. WASTEWATER REUSE CRITERIA IN GREECE A. Andreadakis, E. Gavalaki, D. Mamais, A. Tzimas National Technical University of Athens, Faculty of Civil Engineering Department of Water Resources, Hydraulic and Maritime Engineering 5, Iroon Polytechniou, Zografou, Athens 15780, Greece

2. WASTEWATER REUSE POSSIBILITIES Wastewater reuse for non-potable purposes Agricultural Urban Industrial Recreational Groundwater recharge (to aquifers not used for potable purposes) Wastewater potable reuse Indirect (including groundwater recharge to aquifers used for potable purposes) Direct

3. Water Shortage Adequacy of Water Supply Group III North Europe and several industrialised countries Most of the EU Reuse is envisaged as an interesting concept in the context of sustainability but in practical terms often only industrial reuse (usually in plant) is considered in practice SIGNIFICANCE OF WASTEWATER REUSE

4. GENERAL REUSE STANDARDS Group I For unrestricted irrigation no standards and very limited if any treatment requirement For unrestricted irrigation and other urban and recreational reuse usually the WHO standards are adopted –200-1000 FC/100ml Group II For unrestricted irrigation usually secondary treatment is required with or without disinfection For unrestricted irrigation and other urban and recreational reuse tertiary treatment followed by disinfection is adopted –2-50 FC or TC/100 ml

5. DOMESTIC REUSE

7. URBAN REUSE (potential for Athens)

8. Recommended Guidelines for microbiological and conventional parameters for agricultural wastewater reuse in Greece Fecal coliforms/100 ml BOD 5 (mg/l) SS (mg/l) Turbidity (NTU) Recommended treatment Restricted Irrigation Forests and areas where access to the public is not expected, fodder, industrial crops, pastures, trees (including fruit bearing trees on the condition that during collection the fruits do not come into contact with the ground), seed crops, crops that produce products which are processed before consumption. Spray irrigation should not be practiced. 200 as median value 800 for 95% of samples 25 for 95% of samples 35 for 95% of samples   secondary biological treatment a  disinfection b Unrestricted Irrigation All other crops such as vegetables, vineyards, crops with products which are consumed raw, greenhouses. Unrestricted irrigation allows for different irrigation methods including spray irrigation. 5 for 80% of samples 15 for 95% of samples 100 max value 10 for 80% of samples 2 median value  secondary biological treatment a  tertiary treatment c  disinfection b a. Recommended methods for secondary treatment include various types of activated sludge process, biological filters and rotating biological contactors. Other systems including natural systems and on site systems producing effluents of equivalent quality (BOD/SS = 25/35) can be accepted on the basis of adequate documentation. With respect to nitrogen concentrations in the effluent must be lower than 30 mg/l except in cases of long term surface storage, where a concentration of 15 mg/l for nitrogen and 4 mg/l for phosphorus must be adopted. b. Chlorination, ozonation, or other chemical disinfectants, UV radiation, membrane processes. c. Normally coagulation, flocculation, sedimentation, filtration. Direct or contact filtration can be used if secondary treatment produces effluent with SS concentrations lower than 20 mg/l for 80% of the samples.

9. Recommended Guidelines for microbiological and conventional parameters for urban non-potable reuse, habitat restoration, recreation in Greece Fecal coliforms/100 ml BOD 5 (mg/l) SS (mg/l) Turbidity (NTU) Recommended treatment Landscape areas (cemeteries, freeway landscaping, golf courses, parks), landscape and recreational impoundments, fire fighting, soil compaction, dust control, cleaning roads, sidewalks, toilet and urinal flushing, decorative fountains. 5 for 80% of samples 15 for 95% of samples 100 max value 10 for 80% of samples 2 median value  secondary biological treatment a  tertiary treatment b  disinfection c a. Recommended methods for secondary treatment include various types of activated sludge process, biological filters and rotating biological contactors. Other systems including natural systems and on site systems producing effluents of equivalent quality (BOD/SS = 25/35) can be accepted on the basis of adequate documentation. With respect to nitrogen concentrations in the effluent must be lower than 30 mg/l except in cases of long term surface storage, where a concentration of 15 mg/l for nitrogen and 4 mg/l for phosphorus must be adopted. b. Normally coagulation, flocculation, sedimentation, filtration. Direct or contact filtration can be used if secondary treatment produces effluent with SS concentrations lower than 20 mg/l for 80% of the samples. c. Chlorination, ozonation, or other chemical disinfectants, UV radiation, membrane processes.

10. Recommended Guidelines for microbiological and conventional parameters for industrial reuse in Greece Fecal coliforms/100 ml BOD 5 (mg/l) SS (mg/l) Turbidity (NTU) Minimum recommended treatment a Once through cooling waters 200 as median value 800 for 95% of samples 25 for 95% of samples 35 for 95% of samples   secondary biological treatment b  disinfection c Recirculated cooling systems, boiler and process waters 5 for 80% of samples 15 for 95% of samples 100 max value 10 for 80% of samples 2 median value  secondary biological treatment b  tertiary treatment d  disinfection c a. Additional treatment may be needed depending on the specific requirements of each application. b. Recommended methods for secondary treatment include various types of activated sludge process, biological filters and rotating biological contactors. Other systems including natural systems and on site systems producing effluents of equivalent quality (BOD/SS = 25/35) can be accepted on the basis of adequate documentation. With respect to nitrogen concentrations in the effluent must be lower than 30 mg/l except in cases of long term surface storage, where a concentration of 15 mg/l for nitrogen and 4 mg/l for phosphorus must be adopted. c. Chlorination, ozonation, or other chemical disinfectants, UV radiation, membrane processes. d. Normally coagulation, flocculation, sedimentation, filtration. Direct or contact filtration can be used if secondary treatment produces effluent with SS concentrations lower than 20 mg/l for 80% of the samples.

11. N=N O  e -k  D + a  SS F(N)=F(N O )  e -F(k)  D + F(a)  F(SS)

14. Frequency Chart.000.007.015.022.030 0 37.25 74.5 111.7 149 10.0016.0020.0027.5035.00 5,000 Trials 52 Outliers Forecast: TSS

15. F(N)  F(N O )  e -F(k)  D F(N)  F(a)  F(SS) F(N)=F(N O )  e -F(k)  D + F(a)  F(SS)

21. Agronomic Guidelines of water quality for irrigation

22. Maximum recommended permissible levels of trace elements in reclaimed wastewater Trace Element Max concentration (μg/l) Al (aluminium) 5000 As (arsenic) 100 Be (beryllium) 100 Cd (cadmium) 10 Co (cobalt) 50 Cr (chromium) 100 Cu (copper) 200 F (fluoride) 1000 Fe (iron) 5000 Li (lithium) 2500 Trace Element Max concentration (μg/l) Mn (manganese)200 Mo (molybdenum)10 Ni (nickel)200 Pb (lead)5000 Se (selenium)20 V (vanadium)100 Zn (zinc)2000 Hg (mercury)5