A New Concept for Dual Water Distribution Systems to Ensure Safe Drinking Water
Public Deposited- Last Modified
- February 28, 2019
- Creator
-
Weaver, Christopher C.
- Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
- Abstract
- Since their inception 200 years ago, water distribution systems have been designed for fire protection. Today's practice is presented in AWWA's Manual M31 which is driven by the insurance industry. A minimum pipe diameter of 6 inches or 8 inches more recently is required. Much research and many publications have shown that large diameter pipes produce excessive water residence times within the distribution system, resulting in poor drinking water quality at the consumer's tap. Some of the major health impacts can be caused by continued formation of disinfection by-products within the distribution system and by loss of disinfectant residual. The viability of a dual distribution system that incorporates fire protection into the non-potable system was investigated for the new, master planned community of Briar Chapel that is to be constructed in Chatham County, N.C. and will have a projected population of about 6,000. Costs of a dual distribution system were compared with the conventional infastructure in the current design. Water main sizes along with pumping and storage requirements for fire protection were determined using EPANET software. Two different extents of water reclamation in addition to fire demand were simulated: Option A - irrigation (common green spaces and individual lawns) and Option B - irrigation and toilet flushing. The length-averaged pipe diameter was reduced from 8.6 to 3.4 in. for Option A and to 2.8in. for Option B. While cost for the potable water lines was reduced, the analysis showed a net cost increase by addition of the new reclaimed water network (inclusive of water storage tanks for fire protection) that ranged depending on choice of pipe material from $312,000 to $678,000 for Reuse Option A and from $285,000 to $592,000 for Reuse Option B. These costs were offset by reduction in spray irrigation equipment for land disposal of $190,000 in Reuse Option A and $370,000 in Reuse Option B. In addition, the reduction land area needed for land disposal was 28% in Reuse Option A and 52% in Reuse Option B. The savings translates potentially into a large offset in infrastructure costs if this land can be developed.
- Date of publication
- December 2007
- DOI
- Resource type
- Rights statement
- In Copyright
- Advisor
- Aitken, Michael
- Okun, Daniel A.
- DiGiano, Francis A.
- Singer, Philip
- Degree
- Master of Science in Environmental Engineering
- Academic concentration
- Environmental Engineering
- Degree granting institution
- University of North Carolina at Chapel Hill
- Graduation year
- 2007
- Language
- Deposit record
- e00f1df6-6c31-41ba-867b-150d86a8c8cb
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