Recycling Treated Municipal Wastewater for Industrial Water Use

Section 3
Inventory of Major WWTPs and Potential Industrial Reuse Demands
Table 3.11a. Industrial Water Use in the Minnesota River Watershed
2004 Water Use, mgd
Ground
Industry Category
Water Surface Water Total
Agricultural Processing 11.14 0.00 11.14
Industrial Process Cooling - Once Through 1.88 0.00 1.88
Industrial Processing 0.17 0.00 0.17
Metal Processing 1.31 0.00 1.31
Mine Processing 0.20 0.04 0.24
Non-Metallic Processing 0.43 0.00 0.43
Petroleum - Chemical Processing, ethanol 1.18 0.00 1.18
Pulp and Paper Processing 0.05 0.00 0.05
Sand and Gravel Washing 0.83 1.62 2.45
Steam Power Cooling - Once Through 0.11 326.00 326.11
Total
Source: MDNR, 2004
17.30 327.66 344.96
WWTPs
There are 15 municipal WWTPs in the Minnesota River watershed with design
capacities greater than 1 mgd. As shown in Table 3.11b, there are 3 plants with rated
capacities greater than 10 mgd: Met Council’s Blue Lake and Seneca WWTPs and the
Mankato WWTP. These 15 WWTPs discharged 73 mgd in 2005. The smaller WWTPs
in the watershed have a combined design capacity of nearly 23 mgd, representing
approximately 15% of the WWTP capacity in the watershed.
Industries and Proximity to WWTPs
As shown on Figure 3.11c, there are many industries of various categories residing in
the Minnesota River watershed. Table 3.11c lists the various industries that are within
five miles of a WWTP. Mankato has the largest number of industries in proximity of
its WWTP. There are a variety of industry types utilizing ground water supplies that
could be candidate industries for Mankato, in addition to the near completed
construction of their project with Calpine Corporation (for 6 mgd of reclaimed water).
There are several sand and gravel washing operations in St. Peter, but they are four to
five miles away.
Factors Influencing Potential for Industrial Reuse
The Minnesota River watershed has a diverse geology that provides for three
different ground water areas. Ground Water Area 5 covers the central to western
reaches of the watershed. It is characterized with limited bedrock aquifers, moderate
surficial sand aquifers and limited buried sand aquifers. In the north parts of the
watershed, the surficial and buried sand aquifers are more productive. The eastern
portions are characterized by Ground Water Area 2, which has good bedrock aquifers,
moderate buried sand aquifers, and limited surfical aquifers. Well interference has
occurred in some areas. The ground water contamination susceptibility of this
3-20 Craddock Consulting Engineers
In Association with CDM & James Crook
WWReuseTM1_Sec 3_final.doc