Case Area Baseline Report Århus Public Water Utility Anders Breinholt & Anitha K. Sharma DTU Environment, March 2010 Storm- and Wastewater Informatics Case Area Baseline Report Århus Public Water Utility March 2010 Storm and Wastewater Informatics “SWI” is a strategic Danish Research Project with an overall aim to close the knowledge gaps within prediction and control of current and future conditions in integrated urban wastewater systems. Authors of this Report: Anders Breinholt; DTU Environment Anitha K. Sharma; DTU Environment In Collaboration with: Århus Public Water Utility Address: DTU Environment Department of Environmental Engineering Technical University of Denmark Miljoevej, building 113 DK-2800 Kgs. Lyngby Denmark Phone & Fax +45 4525 1600 & +45 4593 2850 Project Homepage: http://www.swi.env.dtu.dk Case Area Baseline Report Århus Public Water Utility March 2010 Contents 1. OBJECTIVES WITH THIS DOCUMENT.................................................................................................... 2 2. EXPECTED OUTCOME OF THE SWI PROJECT FROM THE PERSPECTIVE OF ÅRHUS PWU.. 2 3. ÅRHUS PUBLIC WATER UTILITY AND SWI .......................................................................................... 2 3.1 ORGANISATION.............................................................................................................................................. 2 3.2 FOCUS AREA FOR SWI................................................................................................................................... 3 4. THE STORM- AND WASTEWATER SYSTEM OF ÅRHUS..................................................................... 6 4.1 THE CATCHMENT AREA.................................................................................................................................. 6 4.2 SEWERAGE COMPONENTS .............................................................................................................................. 7 4.3 WASTE WATER TREATMENT PLANTS .......................................................................................................... 12 4.4 STORM AND WASTEWATER CONTROL STRATEGY:....................................................................................... 17 5. MAJOR ISSUES AT ÅRHUS PWU..................................................................................................................... 18 6. EXISTING SWS MODELS AND MEASUREMENT DATA..................................................................... 24 6.1 MODELLING TOOLS...................................................................................................................................... 24 6.2 MEASUREMENTS.......................................................................................................................................... 26 7. SWI RELEVANT PROJECTS IN THE CASEAREA ................................................................................ 27 7.1 INTEGRATED CONTROL OF ÅRHUS PWU...................................................................................................... 27 7.2 EARLY WARNING OF WATER QUALITY ......................................................................................................... 33 7.3 WEATHER RADAR CONTROL OF SEWER SYSTEMS......................................................................................... 35 REFERENCES.................................................................................................................................................... 36 APPENDIX 1. DETAILS ABOUT THE PLANNED/IMPLEMENTED FILLING AND EMPTYING STRATEGY OF EXISTING AND PLANNED STORAGE TANKS IN MARSELISBORG NORTH CATCHMENT AREA........................................................................................................................................ 39 Case Area Baseline Report Århus Public Water Utility March 2010 1. Objectives with this document The objectives with the “Case Area Baseline Report” are to: - Give an introduction to the Storm- and Wastewater System (SWS) managed by År- hus Public Water Utility (PWU) - Describe relevant issues of Århus PWU that relate to the research project SWI - Give an overview of the future integrated control plans with the SWS - Provide references to more comprehensive literature. This report will thus benefit both the SWI Management Group and the Work package Lead- ers in planning the overall work for the coming years and benefit the researchers/students who will be involved with the SWI project. 2. Expected outcome of the SWI project from the perspective of Århus PWU According to Århus PWU the expected outcomes of the SWI project are1: - Ability to make now- and forecasting of rain with a “needed and sufficient” accuracy in spatial and temporal resolution. - Illustration of real-time modelling and control of integrated and optimized operation of sewerage system and WWTP for minimisation of damages (in a broad context: flood- ing, pollutant emission, resource consumption). - The potential of controlling discharge points i.e. discharging less polluted wastewater (thin wastewater) to streams or lakes before mixed with heavily polluted wastewater. Thin wastewater is defined by concentration of N, P, COD and E-Coli. - At least 1 case that illustrates improved performance by simulations at a level of con- fidence sufficient to convince plant owners and other stakeholders to proceed with demonstration in practical real life. - Come up with solutions that contribute to safe hygienic water quality2 in Lake Brabrand, Århus Å and Århus harbour. - Ideas for retainment/handling of first flush in the wastewater system. 3. Århus Public Water Utility and SWI 3.1 Organisation The Public Water Utility of Århus called “Vand og Spildevand” politically and administratively belongs to the Århus municipal authority under the “Division of Technique and Environment”. The total turnover of “Vand og Spildevand” is 500 mio. DKK and has 220 employees. The re- 1 Answers are based on the questionnaire (Århus Municipality, 2009b) and the material received following the interview 2 Hygenic water quality only meets the requirements for E-coli specified by the bathing water directive. 2 Case Area Baseline Report Århus Public Water Utility March 2010 sponsibilities of PWU Århus are Drinking Water supply, transportation and treatment of wastewater (30-35 mio. m3/year) and urban runoff for approx. 300.000 inhabitants (Århus Municipality, 2008a). 3.2 Focus Area for SWI The total area of Århus Municipality is approx. 525 km2 (35 x 15 km). Figure 3.1 is a map of Århus municipality and the red rectangle shows the selected area (enlarged on the right hand side in the figure) for the research activities of SWI project. Århus PWU have recently launched a plan for a new integrated control strategy (Århus Municipality, 2008b) in this area following the wastewater plan 2006-2009 of Århus Municipality (Århus Municipality, 2005) with the aim to optimise the existing and planned SWS in order to achieve hygienic water quality standard in Århus harbour and Lake Brabrand, because it poses the greatest inte- grated control potential and is also the focus area for the integrated control project called In- tegrated Control of Århus PWU (see chapter 7.1 and 7.2). Figure 3.1: The border of Århus Municipality shown with a thick black line to the left. Adap- ted from (Krüger & Århus Municipality, ??) The storm and wastewater system of Århus is going through drastic changes in these years and one of them is centralization of wastewater treatment in order to save operating costs. 3 Case Area Baseline Report Århus Public Water Utility March 2010 Figure 3.2 gives an overview of the existing WWTP in Århus municipality and future of these WWTPs. As seen from this figure there are 14 WWTPs in Århus municipality and according to this figure centralization of wastewater treatment would ultimately result in 2 large WWTP namely Marselisborg and Egå. This will result in an estimated savings in operational costs by 40% or 29 mil DKK/year (Århus Municipality, 2005). The economic calculus behind the cen- tralisation showed that the close-down of the smaller WWTP´s (all except Viby and Åby) would save the citizens 6-9 mil DKK/year. The focus area of this report consists of the three large WWTP’s namely Viby, Åby and Marselisborg and according to figure 3.2. Viby and Åby WWTP will also be closed down after the end of their expected lifetime, which is after 2017. (Århus Municipality, 2005). Egå will as a starting point, not be considered in SWI context, since this is not in the focus area of SWI. Figure 3.2: Planned stepwise closedown of treatment plants in Århus Municipality (Århus Municipal- ity, 2005) Figure 3.3 shows location of the three recipients Lake Brabrand, Århus Å and Århus harbour, where the most significant overflows/outlets are discharged in the focus area. 4 Case Area Baseline Report Århus Public Water Utility March 2010 Figure 3.3: Lake Brabrand, stream of Århus (Århus Å) and Århus harbour. Lake Brabrand and stream of Århus are highlighted with blue color. 5 Case Area Baseline Report Århus Public Water Utility March 2010 4. The Storm- and Wastewater system of Århus 4.1 The catchment area The catchment area in focus for SWI project and the integrated control project include the catchments surrounding Lake Brabrand, the stream of Århus Å and the Århus harbour and is devided into 3 subcatchments: Åby, Viby and Marselisborg as shown in figure 4.1 (Århus Municipality (2009a; 2008b) and (Krüger & Århus Municipality, XXXX) . The upper