Recycling Treated Municipal Wastewater for Industrial Water Use

TM3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
Specific industrial applications may require the removal of trace constituents in the
wastewater. The technology selected will vary with the constituent and specific
application.
3.4.3 Treatment Technologies for Minnesota Industry Reuse Applications
Approach
One of the objectives of this technical memorandum is to define water reuse system
requirements and costs for Minnesota’s industries. Given the diversity of source water
quality characteristics and varying requirements of the industries in Minnesota, a
technology-based approach is used. Industry-specific water quality requirements are
compared to a set of reclaimed water system supplies, with defined water quality
constituents and concentrations. The different reclaimed supplies are defined by
specific treatment technologies, which provide the basis for estimating costs. A range
of treatment requirements and costs can then be applied to industry categories.
Five types of reclaimed water, listed in Table 8, are used to categorize the reclaimed
water quality options available for specific industrial water supply requirements. The
classification is based on a train of treatment technologies to meet a set of water
quality goals. This classification system is based on treatment of the base WWTP
effluent, which is a secondary activated sludge system with nitrification and
phosphorus removal. New facilities or major expansions could incorporate membrane
bioreactors, which are not considered in this classification system. For comparison
purposes, the effluent quality of membrane bioreactors would be similar to Tertiary 2-
Membrane Filtration. Table 9 identifies the typical water quality constituent
concentrations for the five classes of reclaimed water.
Industry Treatment Requirements
Water use for a significant portion of Minnesota’s industries is tracked through the
Minnesota Department of Natural Resources’ (MDNR) Water Appropriations Permit
program. The water demand analysis of Minnesota’s industries, documented in
Technical Memorandum 1 (June 2006) of this project, used the industry categories
established for the permit program’s database. These same categories are used to
document the treatment requirements and costs for Minnesota’s industries.
Many industries have multiple uses for their total water supply. The quality
requirements can vary with the type of use and many industries currently use
different water supplies to meet their various needs. One of the most significant
industrial uses of water is for cooling. Water can also be used in the industry’s
manufacturing or washing processes, as boiler feed water, for landscape irrigation, or
typical potable uses for employees. Table 10 lists the dominant water uses and the
reclaimed water quality (based on the classification systems defined in Tables 8 and 9)
required for Minnesota industries. Table 11 provides the subcategories for major
industry categories that have a wide range of industry types.
Craddock Consulting Engineers 23
In Association with CDM & James Crook
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