Recycling Treated Municipal Wastewater for Industrial Water Use

Section 5: Summary and Potential Next Steps
Recycling Treated Municipal Wastewater for Industrial Water Use
The continued advances in wastewater and water treatment technology, including reductions in cost,
will benefit the wastewater recycling market.
Costs and System Features
Wastewater recycling is competitive with traditional water supplies in some situations.
Removal of hardness and high salt levels significantly adds to the cost of a recycled wastewater
system.
Cost efficiency improves as wastewater usages increases, favoring systems delivering more than 1
mgd.
The two recycling configurations likely to emerge within the framework of existing WWTPs and
industries in Minnesota are for either one large industrial demand to be met with a dedicated pipeline
or for a cluster of industries to be served from a transmission main. In both configurations, a program
of mixed use that also provides for other uses such as irrigation along the transmission main would
provide additional benefits and cost sharing.
As water resources become limited because of drought or aquifer depletion with excessive
withdrawals, or because supplies become contaminated, the cost difference with traditional supplies
will narrow.
Implementation Issues
Stakeholder workshops successfully defined key issues for Minnesota to consider as the state looks to
wastewater recycling as part of its water conservation program. The stakeholders deemed the issues
addressable.
Environmental Stewardship
— Wastewater recycling is seen as the “right thing to do” and industries are responsive to learning
more and considering this new water supply.
— The wastewater recycling public image needs to move from unknown to positive. Industries are
hesitant to embark in recycling without the public’s perception that this is a positive action.
Regulations
— The case-by-case regulatory approach matches the current permit demand and it is difficult to
justify investment at this time in a new approach to regulating this practice.
— However, the case-by-case approach may deter some recycling projects because there are too
many uncertainties. There are also many unknowns related to the TMDL process or how
recycling will affect NPDES permitted constituents and conditions.
Incentives & Risk
— Without economic incentives it will be difficult for recycled wastewater to compete with the cost
of the traditional water sources until it is a proven water supply in Minnesota.
— There are unresolved industry concerns with risk and liability that need to be addressed before
many industries will consider a recycled wastewater supply.
Data Collection & Research
— Additional municipal WWTP effluent data with specific constituents of concern to industries are
needed to more completely assess wastewater recycling for specific applications and accurately
compare system costs to traditional supplies.
— Colder weather and site-specific water quality concerns need to be explored by testing treatment
technologies. This will also assist in a better assessment of treatment costs.
62 Metropolitan Council Environmental Services