Recycling Treated Municipal Wastewater for Industrial Water Use

Section 3
Inventory of Major WWTPs and Potential Industrial Reuse Demands
Craddock Consulting Engineers 3-7
In Association with CDM & James Crook
WWReuseTM1_Sec 3_final.doc
the radius (to the nearest mile) that captures the top 30-40 industries. Appendix
C provides the complete list.
The facility design capacities and flows are included to compare industrial water
demand to the reclaimed water supply available in a watershed. It is also useful to
compare the historic WWTP flow to the plant’s design capacity. Facilities with
discharge flows significantly less than the design capacity indicate: (1) the area is
planning for growth or (2) there was a change in the area’s industries that caused a
decrease in flow to the WWTP and/or the movement of residents from the area.
Both of these cases provide an incentive for industries to locate in these areas and
benefit from industrial reuse. New growth areas provide the ability to locate and
install conveyance and other infrastructure more economically. Plants with excess
capacity related to the closing of an industry in the area, provide available treatment
capacity for an industry’s waste load. The industry might avoid the costs for their
own treatment facilities and the permitting associated with an independent discharge
to the receiving waters. If water supply problems exist in the area, reuse can also be
factored into the planning and provide another positive reason for an industry to
locate in this community.
Conversely, a facility with current discharge flows near the design capacity, may be a
preferred community for new industry. Assuming the area will experience some
growth, communities with facilities treating flows within 80% of design capacity will
be planning for a wastewater treatment expansion. The design for the expanded
facilities can incorporate the treatment requirements to deliver reclaimed water to
existing or new industries – providing economic incentives for an industry looking for
a water supply, as well as the municipality.
Distances between WWTPs and industries were approximated. It is assumed that the
wells used by the industry are close to the facilities that use the water supply. This
may not always be the case. ‘Distance’ is used as a general criterion to evaluate the
feasibility of specific water reuse applications, recognizing that distance will affect
transmission costs.
Along with the information on existing industries and WWTPs, a synopsis of basin
and regional factors related to industrial growth is provided. Water supply
availability is reviewed on a regional level using the MDNR’s classification of
Minnesota into six ground water areas. 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 3.7b. Appendix D
contains the classification system and supporting documentation (MDNR, 2005).
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
3.7c, 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.