Date of Award

8-2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Civil Engineering

Advisor

Piratla, Kalyan R

Committee Member

Klotz , Leidy

Committee Member

Andrus , Ronald D

Abstract

The water industry is under enormous pressure to provide potable water in circumstances of increasing demands due to population growth, lifestyle change of people and depleting freshwater resources. Deteriorating infrastructure makes the task of meeting the human water consumption needs even more challenging. Distributed water supply systems are currently pursued as a sustainable alternative in arid regions of US to exploit the potential of water reclamation at community or district level to reduce the dependence on freshwater resources. An extension of such a distributed water supply alternative is a complete decentralized supply, which requires on-site water reclamation. The intention of this thesis is to study the reliability improvement when on-site water reclamation systems are installed to complement the existing water supply systems in order to reduce the reliance on freshwater sources. This thesis presents the development of a computational reliability model based on a previously proposed theoretical framework that can be applied to both centralized and decentralized supply scenarios for performance evaluation. The comparative reliability model is demonstrated on a benchmark network that consists of 23 nodes, 31 pipes and 9 loops. The research is carried out in two stages. The first stage is designing the chosen benchmark network to resemble a 50-year old one. The second stage is developing the reliability model to assess the reliability of centralized and decentralized supply scenarios using the same benchmark network as the system skeleton. The model used to evaluate reliability is an integration of a computational algorithm with the EPANET through EPANET toolkit. The results revealed that the scenario where on-site greywater reuse systems supplement existing water supply systems has greater supply reliability of up to 17% when compared with the business as-usual scenario. The reliability analysis presented in this thesis is based on few assumed parameters and a sensitivity analysis is conducted to understand their influence on the research output. Sensitivity analysis revealed that the improvement in reliability decreased with increase in age of the system (t) and failure growth rate (A), whereas it increased with increase in maximum usable reclaimed water (α), efficiency of treatment plant (γ) and the roughness coefficient (K). Overall, the results encourage the adoption of on-site greywater reuse systems from the infrastructure supply reliability standpoint.

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