Recycling Treated Municipal Wastewater for Industrial Water Use

Section 2
Implementation Considerations
Craddock Consulting Engineers
In Association with CDM & James Crook 2-25
TM1-Sec2_0707.doc
the treatment costs for broad industry categories based upon the treatment
technologies typically associated with the water quality requirements for that
industry. This review focuses on industries more prevalent in Minnesota and only
defines the treatment costs, specifically the equipment capital costs. O&M costs are
highly variable with source water quality characteristics and industry finished water
requirements. O&M costs will be reviewed in Task 2 of the project. Similarly, costs
associated with pumping and conveyance facilities are not included in this
preliminary review of treatment costs.
The water supply treatment costs for several industry categories are negligible. Power
generation facilities using once-through cooling processes require large volumes of
water, but of lower quality. In most instances in Minnesota, river water is used with
little to no treatment. Sand and gravel washing operations also have low water
quality requirements and require no additional treatment from the source supply.
Cooling water used for power generation or other industry process needs that uses a
recirculating process has more restrictive water quality requirements. Some smaller
facilities may use a municipal water supply and no other treatment if the water
quality meets the constituent thresholds. Industries using larger volumes of water,
will likely use a ground water supply if it is available. If it is not available, a surface
water source would be used. Higher levels of treatment are required for a surface
water source that is higher in solids, organics, and contains pathogens. Some ground
water supplies high in total dissolved solids (TDS) and other constituents may also
require additional treatment. If a standard chemical addition, coagulation,
flocculation, sedimentation, filtration and disinfection process is used, the capital cost
would be approximately $1.5 per gpd of treatment capacity for a facility treating 1
mgd or less based on cost curves escalated to June 2006 costs [James M. Montgomery,
Consulting Engineers, 1985].
Microfiltration or ultrafiltration may be a more appropriate technology to provide
cooling water for recirculating systems or for boiler feed water, which typically
requires a higher quality water, or for other industry processes. The capital costs for
micro and ultrafiltration decrease with the volume of water processed: costs on a per
mgd basis are much higher for membrane plants less than 1 mgd, decrease rapidly
from 1 to 10 mgd and then the cost per mgd is relatively flat after 10 mgd [AWWARF,
2005]. While these costs are based on larger, municipal system supplies, the lower
volume costs are applicable. The total membrane system cost for a 1 mgd system is
estimated to be $2.1 million for a 0.5 mgd system ($4.20/gpd) and $2.4 million for a 1
mgd system ($2.40/gpd) based on cost curves published in 2005 and escalated to June
2006 costs [AWWARF, 2005].
A majority of industries use municipal water for their industrial processing water
supply. The costs of water supplies in the metro area range from $0.75 to $3.50 per
1,000 gallons of water, based on an analysis of municipal system pricing structures in
2002 [Metropolitan Council, 2004]. Ground water supplies typically have a lower