Recycling Treated Municipal Wastewater for Industrial Water Use

3.0 Treatment
3.1 Industrial Water Quality Requirements
TM3: Recycled Wastewater System Components and Costs
Recycling Treated Municipal Wastewater for Industrial Water Use
There are two water quality drivers that affect the treatment requirements for
reclaimed water:
The regulatory requirements which are typically for the protection of public
health and the environment and focus on microbiological parameters.
The user-specific requirements for the water supply, which in the case of
industries is a very specific set of water quality criteria for a given facility.
3.1.1 Regulatory Requirements
Reclaimed water for industrial use in Minnesota is currently required to meet
regulatory limits based on the California Water Recycling Criteria, Title 22 California
Code of Regulations (Title 22). The complete list of criteria is included in Appendix A,
Exhibit 1. The criteria specific to industrial applications (excluding any irrigation uses)
are listed in Table 1. The Minnesota Pollution Control Agency (MPCA) handles
permitting recycled wastewater as part of the National Pollutant Discharge
Elimination System (NPDES) permit process. The MPCA establishes recycled
wastewater water quality criteria on a case-by-case basis and bases its assessment on
the Title 22 criteria. Therefore, the Title 22 criteria will serve as the basis for selection
of treatment technologies to meet regulatory requirements in this study.
Table 1. California Water Recycling Criteria (Industrial Uses)
Type of Use
Total Coliform
Limits
Treatment
Required
Cooling water where no mist created
≤ 23/100 ml
Process water where no worker contact
Boiler feed
Mixing concrete
1
≤ 240/100 ml
Secondary
(max in any 30- Disinfection
day period)
Cooling water where mist created 2
Process water where worker contact
likely
≤ 2.2/100 ml 1
≤ 23/100 ml
(max in any 30day
period)
Secondary
Coagulation 3
Filtration
Disinfection
Source: Adapted from State of California [2000a].
1
Based on running 7-day median; daily sampling is required.
2
Drift eliminator required; chlorine or other biocide required to treat cooling water to control Legionella
and other microorganisms.
3
Not required under certain conditions.
Craddock Consulting Engineers 5
In Association with CDM & James Crook
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