Wastewater generation & treatment statistics Reliable statistics

1. Wastewater generation & treatment statistics Reliable statistics Intersecretariat Working Group on Environment Statistics Work Session on Water Statistics (Vienna, 20-22 June 2005) Benoît FRIBOURG-BLANC

2. Independent system • Independent system • Separate system • Separate system • UWWTP • UWWTP • Combined system • Combined system • Stormwater overflow • Stormwater overflow • IWWTP • IWWTP Wastewater : from generation to discharge Various pathways Source : L’assainissement des grandes villes, RNDE, France, 1998

3. Wastewater : from generation to discharge Wastewater loading scheme • 4 steps • Water quantity and transfers • pollution quantity and transfers (non conservative) • Equipments and performance Source : Data Collection Manual for the OECD/Eurostat Joint Questionnaire on Inland Waters, Tables 1 – 7, June 2004

4. Definitions for Wastewater Proposed sources organisation NACE/ISIC approach Source : Data Collection Manual for the OECD/Eurostat Joint Questionnaire on Inland Waters, Tables 1 – 7, June 2004

5. Definitions for Wastewater Some characteristics of sources • Only the agent that emit the pollution (avoid double counting) • Point, small point and diffuse sources • A link with NACE/ISIC • Process based vs Source based : NOSE

6. Definitions for Wastewater the collection systems • The first part of the wastewater treatment system, • Many equipments, • Estimation of performance, • Reduced to connection rate, • Private part neglected, • Population served vs connected.

7. Definitions for Wastewater the treatment • Definition / delimitation • Primary, Secondary and Tertiary treatment (JQ: design and real performance) • Investment - working costs / pollution destruction - transfers Source : SANDRE-OIEau 1997

8. Definitions for Wastewater the pollution the direct or indirect introduction, as a result of human activity, of substances or heat into the air, water or land which may be harmful to human health or the quality of aquatic ecosystems or terrestrial ecosystems directly depending on aquatic ecosystems, which result in damage to material property, or which impair or interfere with amenities and other legitimate uses of the environment. (EU Water Framework Directive) • Parameters and substances • Geographical and temporal • Available classification systems (CAS, ELINCS, EINECS)

9. data collection for Wastewater the raw data • Temporal and geographical variations, • High influence of processes and human activities, • Multiple pathways • Reliable monitoring (continuous, quality check…) • High cost of monitoring, combination of monitoring and calculating (formula, emission factors, models, experts)

10. data collection for Wastewater data aggregation • A wide use of thresholds : reliable individual data, • A need to complete the picture, • A need to aggregate for international statistics, • Geographical or temporal aggregation (frequency, quality), • Wide use of all possible methods from monitoring to modelling

11. Wastewater generation and discharge The main conclusions • Reliability is crucial for priority setting • Completeness vs confidence • shared terminology (definitions, data format, nomenclature) EN 1085:1997 wastewater treatment • Not only monitoring but also design capacity, emission factors and other estimations.