Our Experience in Reducing Water Losses by Regulating Pressure in Water Supply Systems

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

2. Pressure Reduction • 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 In our experience pressure control in water supply networks is an effective measure for :

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 • 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 DMA 1, 2009

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

6. Case Studies: Pressure Management • 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 DMA 2, 2007

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. Case Studies: Pressure Management • 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 DMA 3, 2010

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