Recycling Treated Municipal Wastewater for Industrial Water Use

Section 1
Introduction
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In Association with CDM & James Crook 1-3
TM1-Sec1_0707.doc
volume users, it is based on a well-maintained data record that provides an accurate
accounting of the users that are monitored.
The MDNR tracks water use by nine industrial categories, listed in Figure 1.1 and
Table 1.1. Over 60% of the water used in Minnesota is for power generation facilities,
mainly for once-through cooling, supplied mostly by surface waters (as indicated in
Table 1.1 and Figure 1.2). The next largest use of water, about 15% of the total, is as a
potable-quality water supply (waterworks), distributed by municipalities for
domestic, commercial and industrial uses. Nearly two-thirds of the potable-quality
water in Minnesota is supplied by ground water. Water withdrawn by industries
(those not served by waterworks) for various processing needs accounts for about
12% of the total water used in Minnesota.
In terms of 2004 daily average demands, nearly 2,500 mgd of water was used by the
state’s power generation industry and over 500 mgd served as a potable-quality
supply for a variety of uses. Over 400 mgd was withdrawn by industries for direct use
in their business. Year 2004 water records were used for this study for analysis of
industrial water demands on a state-wide basis because it was representative of the
previous four years of record, as documented in Appendix A, and was the last year of
reported data available.
Clearly, the various types of industrial water use represent a major demand on the
state’s water resources. For purposes of this project, the MDNR categories of power
generation and industrial processing represent demands that in theory could use
reclaimed water. Some industries also use municipal potable supplies, but there are
insufficient data on a state basis to identify this portion of the industrial sector.
Recognizing these limitations, the total “industrial water use” (power generation and
industrial processing) in Minnesota is nearly 3 billion gpd, which is roughly 75% of
the total major water use in the state.
Table 1.1. Water Use in Minnesota, 2004
Category Ground Water
Water Use, mgd
Surface Water Total
Air Conditioning 6.0 0.9 6.8
Industrial Processing 56.3 385.4 441.7
Major Crop Irrigation 174.9 27.6 202.5
Non-Crop Irrigation 20.3 5.5 25.8
Power Generation 3.6 2,375.1 2,378.8
Special Categories 18.9 14.5 33.3
Temporary 4.2 0.7 4.9
Water Level Maintenance 4.8 95.4 100.2
Waterworks 354.6 201.3 555.9
Total 643.6 3,106.3 3,749.8
Source: MNDR, 2004