Pressure Management by Combining Pressure Reducing Valves and Pumps As Turbines for Water Loss Reduction and Energy Recovery

Pressure Management by Combining Pressure Reducing Valves and Pumps As Turbines for Water Loss Reduction and Energy Recovery

S. Parra S. Krause

Sanitary Engineering and Waste Management, University of the Federal Armed Forces Munich, Germany.

Page: 
89-97
|
DOI: 
https://doi.org/10.2495/SDP-V12-N1-89-97
Received: 
N/A
| |
Accepted: 
N/A
| | Citation

OPEN ACCESS

Abstract: 

Conventional pressure reducing valves (PRVs) are often used in water distribution systems for pressure control and water loss reduction. Nevertheless, depending on the conditions in the network, advanced pressure management approaches might be more suitable. In this study, the potential water loss reduction for an intelligent system that combines PRVs and pumps as turbines (PATs) in a pilot study in Germany was estimated. The aim of the proposed system is to recover the pressure energy in the supply network by transforming it into electricity and, at the same time, contribute to the reduction of water losses and material stress. In order to evaluate the pressure situation and predict the water savings of the different pressure management strategies in the studied supply area, hydraulic modelling was used. Using the calibrated model, the optimal outlet pressure for the installed PRV and for the intelligent pressure control system was calculated, taking into account the pressure at the critical point as a boundary condition. Furthermore, the pressure-dependant leakage flow was simulated using the emitter coefficient feature in EPANET. Here, a pressure exponent of 1.5 was used, assuming uniform background leakage along the distribution system. For the analysed network, 28.5% and 45% water savings are expected for the fixed and for the advanced pressure management strategy, respectively. The predicted water savings and the leakage assumptions are to be verified either on field or experimentally. This study concludes that hydraulic modelling is essential for assessing water supply networks, as well as for optimizing current pressure management strategies and predicting its benefits.

Keywords: 

EPANET, hydraulic modelling, pressure management, pressure reducing valve, pump as turbine, water loss reduction

  References

[1] Haakh, F., Holmer, F. & Nill, A., Energieeffizienz in der Fernwasserversorgung am Beispiel der Landeswasserversorgung. Beitrag 5, LW-Schriftenreihe 2013, 54–66, 2013.

[2] Kramer, M. & Wieprecht, S., Untersuchungen zum Einsatz von Kleinturbinen in der Trinkwasserversorgung. In wat+gat (spezial) Tagungsband 2, 2012.

[3] Sitzenfrei, R., Berger, D. & Rauch, W., Design and optimization of small hydropower systems in water distribution networks under consideration of rehabilitation measures. Urban Water Journal, pp. 1–9, 2015. http://dx.doi.org/10.1080/1573062X.2015.1112410

[4] Statista, Wasserverluste in der öffentlichen Wasserversorgung in Deutschland von 1999 bis 2013, available at: http://de.statista.com/statistik/daten/studie/155684/umfrage/wasserverluste-in-der-oeffentlichen-wasserversorgung-seit-1991/ (accessed 20 April 2016).

[5] Gomes, R., Sousa, J. & Marques, A.S., The influence of pressure/leakage relationships from existing leaks in the benefits yielded by pressure management. Water Utility Journal, 5, pp. 25–32, 2013.

[6] Lambert, A., What do we know about pressure-leakage relationships in distribution systems? In System Approach to Leakage Control and Water Distribution Systems Management. IWA International Specialised Conference, 2001.

[7] McKenzie, R., Mostert, H. & Jager, T., Leakage reduction through pressure management in Khayelitsha: Two years down the line. In Biennial Conference and Exhibition of the Water Institute of Southern Africa, Water Institute of Southern Africa, 2004

[8] Schwaller, J. & van Zyl, J.E., Modeling the pressure-leakage response of water distribution systems based on individual leak behavior. Journal of Hydraulic Engineering, 141(5), 4014089, 2015. http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0000984

[9] DVGW, Merkblatt W 335: Druck-, Durchfluss- und Niveauregelung in Wassertransport und -verteilung. Wirtschafts- u. Verlagsges. Gas u. Wasser, Bonn, 2000.

[10] Deutsche Gesellschaft für Internationale Zusammenarbeit & VAG Armaturen GmbH, Guidelines for water loss reduction. A focus on pressure management, 2011.

[11] McKenzie, R. & Wegelin, W., Implementation of pressure management in municipal water supply systems. IWA Water Press, 0309, 2009.

[12] Rossman, L., EPANET 2, Users Manual, 2000.

[13] Karadirek, I.E., Kara, S., Yilmaz, G., Muhammetoglu, A. & Muhammetoglu, H., Implementation of hydraulic modelling for water-loss reduction through pressure management. Water Resources Management, 9, 2012.

[14] Walski, T., Chase, D., Savic, D., Grayman, W., Beckwith, S. & Koelle, E., Advanced Water Distribution Modeling and Management, Bentley Institute Press, Exton, PA, 2003.

[15] Parra, S., Krönlein, F., Krause, S. & Günthert, W., Energiegewinnung imWasserverteilungsnetz durch intelligentesDruckmanagement – EWID, energie | wasser-praxis, 12, 2015.

[16] DVGW, Arbeitsblatt W 392: Wasserverlust in Rohrnetzen – Ermittlung, Überwachung, Bewertung, Wasserbilanz, Kennzahlen. Wirtschafts- u. Verlagsges. Gas u. Wasser, Bonn, 2003.

[17] DVGW, Arbeitsblatt GW 303-1: Berechnung von Gas- und Wasserrohrnetzen - Teil 1: Hydraulische Grundlagen, Netzmodellierung und Berechnung. Wirtschafts- u. Verlagsges. Gas u. Wasser, Bonn, 2006.

[18] Ulanicki, B., Bounds, P., Rance, J.P. & Reynolds, L., Open and closed loop pressure control for leakage reduction. Urban Water, 2(2), pp. 105–114, 2000. http://dx.doi.org/10.1016/S1462-0758(00)00048-0

[19] DVGW, Arbeitsblatt W 400-1: Technische Regeln Wasserverteilungsanlagen (TRWV); Teil 1: Planung Oktober 2004. Wirtschafts- u. Verlagsges. Gas u. Wasser, Bonn, 2004.

[20] Hamilton, S. & McKenzie, R.S., Water Management and Water Loss, IWA Publishing: London, UK, 2014.