Recycling Treated Municipal Wastewater for Industrial Water Use

Section 2: Recycled Wastewater Demand & Supply
Recycling Treated Municipal Wastewater for Industrial Water Use
2.2 Regional Inventory
Watershed Analysis Overview
Regional demand and supply were analyzed on a watershed basis to provide a more detailed account of
industrial demand and proximity to a treated wastewater supply. Figure 2.7 identifies the ten major
watersheds in Minnesota. This section of the report focuses on the Lower Mississippi River watershed as
an example of the analysis provided for each watershed documented in Volume II-Appendix 1.
Indices on the availability of ground water supplies and the susceptibility of these supplies to
contamination were also applied regionally to determine areas for which wastewater recycling may help
protect ground water resources. Water supply availability is reviewed on a regional level using the
MDNR’s classification of Minnesota into six ground water areas (MDNR, 2005). The areas are
categorized by the general availability of ground water in the bedrock and two overlying sediment layers
classified as surficial sands and buried sands, shown in Figure 2.8. Appendix II-1 (Appendix D) contains
the classification system and supporting documentation. Additional information on quantity and quality of
ground water is summarized from the MPCA’s regional ground water profiles (MPCA, 1995). The
statewide assessment of susceptibility to ground water contamination (MPCA, 1989), as shown in Figure
2.9, is also used to identify ground water supply issues. These assessments by MDNR and MPCA provide
higher level indicators of ground water quantity and quality concerns that can be applied uniformly across
the state.
Industrial Water Use – Lower Mississippi River Watershed
The Lower Mississippi River watershed has a diverse base of industries, as summarized in Table 2.4 and
Figures 2.10 and 2.11. The largest water use is related to power generation facilities (nuclear power plant,
steam power cooling and miscellaneous power generation uses). Over 570 mgd of water was used for
power generation in 2004, of which all but 1 mgd was obtained from surface water supplies. The Prairie
Island Nuclear Plant used over 500 mgd in 2004 and another 70 mgd was used for once-through cooling
at the Xcel facility near Red Wing and the Rochester Public Utilities plant. There are several agricultural
processing facilities in this watershed with a combined water use of 2.9 mgd in 2004. Flint Hills
Resources withdrew 6.5 mgd from its set of wells for processing of petrochemical products.
Table 2.4. Industrial Water Use in the Lower Mississippi River Watershed
2004 Water Use, mgd
Industry Category Ground Water Surface Water Total
Agricultural Processing 3 0 3
Industrial Process Cooling - Once Through