Recycling Treated Municipal Wastewater for Industrial Water Use

TM3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
Table 15. Pump Station Unit Costs
Capacity, mgd Capital Cost, $/gpd
≤ 0.5 0.61
0.5 to 7.5 0.49
≥ 7.5 0.40
Source: CDM, 2006 & 2003
5.4.4 Transmission Piping
Transmission piping is a significant cost of the base system. For this study, the cost
model was developed to account for a range of transmission main sizes and lengths,
providing a family of cost curves. These cost curves, based on flow and pipe length,
allow one to estimate the cost of transmission piping from a WWTP to an industry.
Capital Costs
The transmission system is a force main from the WWTP to an industry or a group of
industries. Pipe materials for reclaimed water mains are typically polyvinyl chloride
pipe (PVC) , DR 18, Class 150, AWWA Specifications C-900 and C-905 with push-on
joints, or ductile iron pipe (DIP), Class 51, with push-on joints and cement lining on
the inside and a bituminous coating (16 mils DFT) on the outside. For this cost model,
it is assumed that all mains will be PVC, DR 18, Class 150 for pipe 24 inch or less in
diameter and DIP Class 51 for pipe larger then 24-inch.
The unit cost for materials and labor to install reclaimed water piping are summarized
in Table 16. Construction and project costs are provided. The unit costs were
developed from a transmission cost tool documented in Appendix B. These compare
to force main interceptor costs (MCES, 2006a & 2006b) and water distribution system
costs (Gumerman et al, 1992).
The reclaimed water transmission piping is sized to convey the peak hour demand
and to maintain a target velocity at the peak hour demand of 5 to 7 feet per second
(fps). A peaking factor of 3.0 (peak hour/annual average) is assumed for this study. It
is recognized that peak hour requirements can be much higher for some industries,
particularly with batch or shift related process activity. A peaking factor of 3.0
assumes that there is a main pipeline with laterals to multiple facilities and peak flows
of the various industries do not all coincide.
An overall minimum target pressure of 40 pound per square inch (psi) was assumed
at the delivery point. This is a pressure that is suitable for most cooling water systems
(one of the largest potential uses of reclaimed water for Minnesota’s industries).
The annual average day reclaimed water demand evaluated with this cost model
ranges from 0.1 to 30 mgd. Regression analysis was performed to find the best fit line
to estimate pipeline capital costs for a given flow at given pipe lengths. Appendix B
provides the details of these analyses.
32 Craddock Consulting Engineers
In Association with CDM & James Crook
TM3-Component&Costs_0707