JWARP  Vol.12 No.9 , September 2020
A Comparison of the Operational Energy Demand of Both Low Pressure and Vacuum Collection Systems
Abstract: Climate change is regarded as the greatest threat to society in the coming years, and directly affects the water industry; with changes in temperature, rainfall intensities and sea levels resulting in increased treatment and subsequent energy costs. As one of the largest global consumers of energy, the water industry has the opportunity to significantly prevent climate change by reducing energy usage and subsequent carbon footprints. Wastewater treatment alone requires an estimated 1% - 3% of a country overall energy output while producing 1.6% of its global greenhouse gas emissions; over 75% of which can be due to the collection system. Gravity flows should therefore be incorporated where possible, reducing pumping requirements and therefore minimizing costs and subsequent carbon footprints. This study has assessed the operational energy usage of the alternative collection systems low pressure and vacuum, for use in situations in which a conventional gravity system is not practicable. This was carried out through hypothetical scenario testing using design parameters derived from literature, generating 60 hypothetical collection mains with variations in population, static head and main length. From this study, it was found that the energy demand of a low pressure system is 3.2 - 4.2 times greater than that of its equivalent vacuum system in the same scenario. Energy demand for both systems increases with population, static head and main length. However, population and therefore flow changes were found to have the greatest effect on the energy usage of both systems. Therefore, flow reduction measures should be adopted if the decarbonization of the water industry is to be achieved.
Cite this paper: McCullough, P. and McDermott, R. (2020) A Comparison of the Operational Energy Demand of Both Low Pressure and Vacuum Collection Systems. Journal of Water Resource and Protection, 12, 729-740. doi: 10.4236/jwarp.2020.129044.

[1]   World Commission on Environment and Development (1987) Our Common Future. Oxford University Press, Suffolk.

[2]   Reckien, D., Creutzig F., Fernandez, B., Lwasa, S., Tovar-Restrepo, M., Mcevoy, D., et al. (2017) Climate Change, Equity and the Sustainable Development Goals: An Urban Perspective. Environment and Urbanization, 29, 159-182.

[3]   Læsoe, J., Schnack, K. and Breiting, S. (2009) Climate Change and Sustainable Development: The Response from Education—Cross-National Report. International Alliance of Leading Educational Institutes, Copenhagen.

[4]   Zolghadr-Asli, B., Bozorg-Haddad, O., et al. (2017) Strategic Importance and Safety of Water Resources. Journal of Irrigation and Drainage Engineering, 143, 1-6.

[5]   NI Water (2018) Annual Information Return 2018 for Public Domain.

[6]   Ashley, R., Blackwood, D., Butler, D., Davies, J., Jowitt, P. and Smith, H. (2003) Sustainable Decision Making for the UK Water Industry. Proceedings of the Institution of Civil Engineers: Engineering Sustainability, 156, 41-49.

[7]   Capodaglio, A.G. and Olsson, A. (2020) Energy Issues in Sustainable Urban Wastewater Management: Use, Demand Reduction and Recovery in the Urban Water Cycle. Sustainability, 12, 266.

[8]   Lu, L., Guest, J.S., Peters, C.A., Zhu, X., Rau, G.H. and Ren, Z.J. (2018) Wastewater Treatment for Carbon Capture and Utilization. Nature Sustainability, 1, 750-758.

[9]   NI Water (2019) Annual Report & Accounts 2018/19.

[10]   Roux, P., Mur, I., Risch, E. and Boutin, C. (2011) Urban Planning of Sewer Infrastructure: Impact of Population Density and Land Topography on Environmental Performances of Wastewater Treatment Systems. The LCM 2011 International Conference on Life Cycle Management, Berlin, 28-31 August 2011.

[11]   McDermott, R., Solan, B., McCord, S. and Littlewood, K. (2019) Irish Water and Scottish Water: A Comparison. Journal of Water Resource and Protection, 11, 1064-1089.

[12]   Hensley, W.T. (2012) Wastewater Collection Systems Comparison. 2012 Wastewater Purification and Reuse International Conference, Heraklion, 28-30 March 2012.

[13]   Tebbutt, T.H.Y. (2013) Basic Water and Wastewater Treatment. 2nd Edition, Butterwell & Co., London.

[14]   Zhao, W., Beach, T.H. and Rezgui, Y. (2016) Optimization of Potable Water Distribution and Wastewater Collection Networks: A Schematic Review and Future Research Directions. IEEE Transactions on Systems, Man and Cybernetics, 46, 659-681.

[15]   Elawwad, A., Ragab, M. and Abdel-Halim, H. (2014) Vacuum Sewerage System in Developing Regions and the Impact on Environmental Management. Proceedings of the 4th International Conference on Environmental Pollution and Remediation, Prague, 11-13 August 2014.

[16]   Gikas, P., Ranieri, E., Sougioultzis, D., Farazaki, M. and Tchobanoglous, G. (2017) Alternative Collection Systems for Decentralized Wastewater Management: An Overview and Case Study of the Vacuum Collection System in Eretria Town, Greece. Water Practice and Technology, 12, 604-618.

[17]   Islam, M.S. (2016) Comparative Evaluation of Vacuum Sewer and Gravity Sewer Systems. International Journal of System Assurance Engineering and Management, 8, 37-53.

[18]   Terryn, I.C.C., Lazar, I., Nedeff, V. and Lazar, G. (2014) Conventional vs. Vacuum Sewerage System in Rural Areas and Economic and Environmental Approach. Environmental Engineering and Management Journal, 13, 1847-1859.

[19]   Capodagilio, A.G. (2017) Integrated, Decentralized Wastewater Management for Resource Recovery in Rural and Peri-Urban Areas. Resources, 6, 22.

[20]   The Water Research Foundation (2010) Performance & Cost of Decentralized Unit Process.

[21]   United States Environmental Protection Agency (2002) Wastewater Technology Fact Sheet: Sewers, Pressure.

[22]   Miszta-Kruk, K. (2016) Reliability and Failure Rate Analysis of Pressure, Vacuum and Gravity Sewer Systems Based on Operating Data. Engineering Failure Analysis, 61, 37-45.

[23]   Molatore, T.L. (2017) Operational Cost of Two Pressure Sewer Technologies: Effluent (STEP) Sewers and Grinder Sewers.

[24]   Burden, D.G., Anderson, D.L. and Zoeller, P. (2003) Septic vs. Sewer: A Cost Comparison for Communities in Sarasota County, Florida. Proceedings of Water Environment Federation, 2004, 319-343.

[25]   Engin, G.O. and Demir, I. (2006) Cost Analysis of Alternative Methods for Wastewater Handling in Small Communities. Journal of Environmental Management, 79, 357-363.

[26]   Kaner, C.J.D. (2013) An Introduction to Scenario Testing. Florida Institute of Technology, Melbourne, 1-13.

[27]   Yu, P.L.H., Li, W.K. and Ng, F.C. (2014) Formulating Hypothetical Scenarios in Correlation Stress Testing via a Bayesian Framework. The North American Journal of Economics and Finance, 27, 17-33.

[28]   Airvac (2008) Design Manual.

[29]   British Water (2013) Flows and Loads. 4th Edition, British Water, London.

[30]   Irish Water (2018) Code of Practice for Wastewater Infrastructure.

[31]   Redivac (2020) Vacuum Sewers: Vacuum Pipework.

[32]   Edgeplast Ireland Ltd. (2020) PE Pipe Chart.

[33]   Environment One (2020) Low Pressure Sewer Systems Using Environment One Grinder Pumps.

[34]   Busch (2020) MINK MM—For Rough Vacuum Industrial Applications.

[35]   Environment One (2020) D-Series DH071 & DR071 Grinder Pump Station.

[36]   Department for Business, Energy & Industrial Strategy (2019) Greenhouse Gas Reporting: Conversion Factors 2019.

[37]   Committee on Climate Change (2019) Net Zero—The UK’s Contribution to Stopping Global Warming. Report. London.