1. Our Experience in Reducing Water Losses by Regulating Pressure in Water Supply Systems November 2011, Dubai, UAE Prof. Dr. Dipl.-Eng. Gancho Dimitrov Head of Department: Water Supply, Sewage and Purification of Water at at the University of Architecture, Civil Engineering and Geodesy, Sofia, Bulgaria

2. Pressure Reduction In our experience pressure control in water supply networks is an effective measure for : the reduction of water loss and water consumption the reduction of the accident rate abolition of restrictions on traffic in the streets the reduction of operating costs the substantial reduction in investment the removal of less amounts of water from the water sources providing the necessary ecological balance of ecosystems

3. Types of pressure control, and our research results By maintaining constant pressure after the control valve By maintaining constant pressure after the control valve through water consumption or for specific periods of time; Maintaining a minimum pressure through the critical point of the water supply network. individual zones in 45 residences, 120 control valves reduction of water losses from 15% to 50% of the average water consumption success in reducing accidents by 50% to 90%

4. Case Studies: Pressure Management DMA 1, 2009 Total length of water network: 38 127 m House connections:1 327 Number of people: 23 209 Maximum pressure: 9.1 bar Pressure regulator: DN 300 Output pressure: 5 bar

5. Fig.1 Change in water consumption at the beginning of the zone Results a) period from 12-19 January 2007 before installing the pressure valve; b) period from 14-22 June after adjusting pressure.

6. DMA 2, 2007 Total length of water network: 75 834 m House connections: 6 550 Number of people: 27 400 Pressure regulator: DN 600 Outlet pressure by night: 3,5 bar Outlet pressure by day: 5,0 bar Case Studies: Pressure Management

7. Results Fig. 2 Change in water consumption at the beginning of the zone for the period from 10-15 August 2007 Fig. 3 Change in water pressure at the beginning of the zone for the period from 10-15 August 2007

8. Results Fig. 4 shaft with valves and pressure reducing valve with a diameter of DN 600 with two operation modes (with 5 bar pressure and 3,5 bar) Effect: Reduction: Water losses by 20% Number of accidents by 75% Investment recovery period – 1 year

9. DMA 3, 2010 Total length of water mains: 104 818 m Number of people: 100 000 Pressure regulators: DN 600 and DN 400 Input pressure: 4,7 bar Output pressure: 3,7 bar Case Studies: Pressure Management

10. Results Fig. 5 Installation - Main control valve with DN600 with a bypass line Effects Reduction: Water loss reduction 1,2 mln m3/ per year Number of accidents by 50% Investment recovery period - 1 year

11. CONCLUSIONS Pressure control is a relatively efficient way to reduce water losses and especially the number of accidents. Investment recovery period for pressure regulating is very short (from a few months to 1 year). Reduction of water losses by pressure control has a multiplier effect. It reduces operational costs and investments for new pipelines, pumping stations, treatment plants, and natural wastewater.

12. for questions and contact: Prof. Dr. Dipl.-Eng. Gantcho Dimitrov E-Mail: info@wato.bginfo@wato.bg Mobile: +359 888 305525 Web: www.WATO.bgwww.WATO.bg Thank you for your attention!