Recycling Treated Municipal Wastewater for Industrial Water Use

Costs and Planning Considerations
Section 3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
The generalized costs for recycled wastewater systems developed in this study confines costs to discreet
projects for a set of basic assumptions. As municipalities and industries evaluate recycling opportunities,
an integrated approach to handling water infrastructure needs for the community can be used to evaluate
the impacts on other system costs. Some considerations are provided below.
An accurate comparison of costs for the higher quality water must include the industry’s onsite treatment
cost and cannot be compared solely to the incoming water supply cost. Most industries requiring Tertiary
4 reclaimed water have their own onsite treatment systems to provide this water quality. In many cases,
the industry provides this additional treatment to potable supplies. Some industries also have treatment
processes to provide water of similar quality to Tertiary 1-3 recycled wastewater. With water
conservation practices promoting cooling systems with higher levels of recirculation there will be the
need to use a higher quality of incoming water so that the concentrations of the recycle do not cause
corrosion or scaling problems.
Specific facility planning activities should evaluate the relationship of recycled wastewater system with
potable water system infrastructure. For some communities, recycled wastewater systems provide an
alternative to potable water supply system capital expenditures. Increased domestic demand can be met
without expansion of the potable water distribution system if a portion of the industrial sector uses
recycled wastewater and the total demand for the potable water system is kept constant. A complete
analysis of a recycled wastewater system needs to integrate the entire water resources planning of
communities and regions.
This cost analysis was based on treating WWTP effluent from an advanced secondary treatment process.
Wastewater recycling practices can also be integrated into the design and construction of new WWTPs. It
may be more cost-effective to implement appropriate treatment technologies into the main WWTP
process train and construct new pipelines and facilities, rather than retrofit existing ones. Also, with new
WWTP construction, a recycled wastewater pipeline can be integrated into the potable and collection
system infrastructure, resulting in total system cost reductions. New WWTP site selection can also
include comprehensive planning to integrate industrial parks in close proximity to wastewater facilities.
3.6 Summary
The economic viability of wastewater recycling in Minnesota will depend on the specific match of
WWTP effluent quality to an industry’s water quality requirements, the system capacity, transmission
distance, and the availability of traditional water supplies in the area. The major conclusions from this
study’s assessment of recycled wastewater quality and system costs include the following:
Recycled wastewater can be competitive with traditional water supplies in some cases.
Removal of hardness and high salt levels significantly adds to the cost.
Cost efficiency improves as recycled wastewater usage increases and favors systems delivering more
than 1 mgd.
Emerging contaminants of concern will likely be a future issue for wastewater recycling applications
as it will for all water supplies.
Historic records of important constituents of concern for industrial water uses are not usually available
for WWTP effluent and are needed to fully evaluate alternative water supplies.
This study provided a high-level assessment that estimated a range of costs for low to high quality
water supplies. WWTP-specific water quality and specific industrial treatment requirements must be
thoroughly assessed in the evaluation of recycled wastewater system costs.
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