Recycling Treated Municipal Wastewater for Industrial Water Use

Section 2
Implementation Considerations
Conservation – conserves natural waters for potable supplies
Reliable supply – reclaimed water is nearly always available, not affected by
droughts
Pollution abatement – alternative to discharge to environmentally sensitive waters
Economically attractive supply – may be less costly than treatment needed for
discharge or alternative sources of supply
Regulatory or statutory mandates – regulatory or statutory requirement to use or
consider reclaimed water for certain water demands under certain conditions
In Minnesota, a key driver for industrial reuse of treated wastewater will be the lack of
an adequate local water supply of appropriate quality or quantity. If sufficient supply is
available, but of a poorer quality than reclaimed water, the treatment costs might favor
reuse. Similarly, if an appropriate quality water is available, but at a significant distance
and requires conveyance and annual pumping costs, then reuse may be more costeffective.
While Minnesotans are embracing conservation measures and water supply
plans emphasize reliability in supply, conservation and reliability most likely will be
added benefits, not the main driver to spur industrial water reuse. Municipalities in
Minnesota, particularly in developing areas, may seek to foster relationships with reuse
customers because of increased pressures to reduce the discharge of pollutants to the
state’s waterways. Minnesota’s industries, particularly if located or planned for location
in proximity to a WWTP, could be sought as partners in the continued conservation and
protection of Minnesota’s water resources.
2.2 Regulatory Requirements
Current Water Reuse Practice in Minnesota
Minnesota is one of several states that have not developed state water reuse criteria.
Currently, Minnesota uses California’s Water Recycling Criteria [State of California,
2000a], as summarized in Table 2.1, to evaluate water reuse projects on a case-by-case
basis.
In Minnesota, water reuse requirements are included in NPDES permits administered
by the Minnesota Pollution Control Agency. A change in the location of a wastewater
treatment facility’s discharge (as would be required for a reuse application) or any
modifications to a facility to provide treatment and conveyance for a reuse application
requires an NPDES permit modification.
There are several rural Minnesota facilities that discharge their effluent for agricultural
irrigation purposes, typically because there is not a receiving stream with available load
capacity. Small systems are also being installed for golf course irrigation. The largest
water reuse application in Minnesota will be implemented in 2006 as the City of
Mankato provides treated wastewater effluent to the Mankato Energy Center. Over 6
mgd of water will be provided for cooling and process water needs. Section 2.5
provides additional information on the Mankato industrial reuse project and other
reuse applications in Minnesota.
2-2 Craddock Consulting Engineers
In Association with CDM & James Crook
TM1-Sec2_0707.doc