title: The cost of hybrid waste water systems: A systematic framework for specifying minimum cost-connection rates.
abstract: To determine the optimal connection rate (CR) for regional waste water treatment is a challenge that has recently gained the attention of academia and professional circles throughout the world. We contribute to this debate by proposing a framework for a total cost assessment of sanitation infrastructures in a given region for the whole range of possible CRs. The total costs comprise the treatment and transportation costs of centralised and on-site waste water management systems relative to specific CRs. We can then identify optimal CRs that either deliver waste water services at the lowest overall regional cost, or alternatively, CRs that result from households freely choosing whether they want to connect or not. We apply the framework to a Swiss region, derive a typology for regional cost curves and discuss whether and by how much the empirically observed CRs differ from the two optimal ones. Both optimal CRs may be reached by introducing specific regulatory incentive structures.
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Institute of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093 Zurich, Switzerland. Electronic address: sven.eggimann@eawag.ch.
authors: Sven
authors: S
authors: Eggimann
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Faculty of Geosciences, Utrecht University, Heidelberglaan 2, NL-3584 CS Utrecht, The Netherlands.
authors: Bernhard
authors: B
authors: Truffer
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Institute of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093 Zurich, Switzerland.
authors: Max
authors: M
authors: Maurer
mesh_terms: D003247:Conservation of Natural Resources; D003365:Costs and Cost Analysis; D012499:Sanitation; D014186:Transportation; D062065:Wastewater
chemical_list: D062065:Wastewater
keywords: Decentralised waste water management; Engineering economics; Geographical information system; Sustainability transition; Urban structural unit; Urban water management