Recycling Treated Municipal Wastewater for Industrial Water Use

TM3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
5.4.5 Base Water Reuse System Cost Analysis Results
The cost curves developed for the base system indicate that a reclaimed water supply
system can be cost competitive with potable water supplies in Minnesota. This
assumes that an advanced secondary wastewater treatment plant effluent water
quality is available from existing facilities and is suitable for that industry, or that
industry already has a treatment system in place for its existing supply that can be
used (or upgraded at a nominal cost for a reclaimed supply).
As shown in Figure 5 and tabulated in Appendix C, a reclaimed water system
designed for an annual average flow of less than 0.5 mgd is not expected to be
competitive with most potable water supplies, except where the industry is in close
proximity to the WWTP. At 1 mgd, the cost of service is comparable or less than a
typical potable water supply system cost of $2/1000 gallons for systems under 10
miles. As the system capacity increases to 5 mgd, a 10-mile system costs about
$1/1000 gallons. For flows greater than 5 mgd, as shown in Figure 6, costs drop below
$0.60/1000 gallons, even at a distance of 10 miles for 30 mgd.
Potable water supplies in the Minneapolis/St. Paul area range from $1-$3/1000
gallons and fluctuate around that cost in other areas of Minnesota. Some rural water
systems have costs over $5.00/1000 gallon. Water reuse system costs are compared to
potable water supply costs to provide a perspective on the water supply market for
Minnesota. Those industries with their own water supply will typically have much
lower costs than for a potable supply. A comparison to a potable supply is reasonable
for smaller water using industries (less than 0.5 mgd water demand), which often use
potable supplies, particularly in urban areas. If higher quality water is required, then
potable supplies are also used and at higher volumes.
Technical Memorandum 1: Implementation Issues and Customer Inventory produced
for this project evaluated industries within a 5-mile range of metro area WWTPs and
larger ranges in the rest of Minnesota. The base system cost of service curves indicate
that service to those industries within 5 miles of a WWTP with a combined reclaimed
water demand of 1 mgd or more could be provided at about $1.00/1000 gallons or
less, making it competitive with potable supplies.
The base system provides a water quality that could possibly be suitable for a oncethrough
cooling process or sand and gravel washing. It would also be sufficient for
irrigation of restricted areas on industrial site grounds. To meet the anticipated water
requirements for much of Minnesota’s industrial water demand, additional treatment
at the WWTP or the industry site will be required. Given the high hardness in
Minnesota’s source waters and high salt concentrations in wastewater (elevated
chloride concentrations have been attributed to home softening system brine
discharges), additional treatment may be necessary for the intended industrial water
use. The treatment costs for a range of industrial uses are the subject of Section 5.6.
34 Craddock Consulting Engineers
In Association with CDM & James Crook
TM3-Component&Costs_0707