Recycling Treated Municipal Wastewater for Industrial Water Use

Treatment Requirements and Technologies
Section 2
Implementation Considerations
The treatment requirements for industrial reuse applications will be based on the
quality of the source water used by a community, industries discharging to the
wastewater treatment facility, the wastewater treatment processes, and the intended
use of the water by the industry. The type of technology selected will depend on
whether treatment is incorporated into the wastewater treatment facility’s process
train, at the industry, or at a satellite facility along the distribution line that could
benefit multiple customers. If storage is required for a constant flow, additional
treatment may be required. With all these variables, the treatment process and
conveyance system selected is certainly a site and case-specific one.
This subsection presents an overview of treatment processes used to provide
reclaimed water to industries, as well as other customers. More specific treatment
requirements will be identified for the Minnesota candidate industries selected under
Task 2 work activities and will be presented in the project final report.
Wastewater Plant Effluent Quality
The constituent concentrations in wastewater plant effluent are different for every
facility. However, given common permit limits, some constituent concentrations are
universal to most facilities based on the general treatment trains as presented in Table
2.10. In Minnesota, all municipal wastewater treatment facilities have secondary
treatment and many have nutrient removal processes, particularly for nitrogen. Many
plant upgrades will likely include the requirement for phosphorus removal. There are
few facilities in Minnesota that have filtration processes, but this practice may become
increasingly common as receiving streams reach their maximum load capacity and
additional pollutant removal is necessary.
Table 2.10. Typical Wastewater Treatment Plant Effluent Quality
Constituent Secondary
Treatment
Constituent Concentration, mg/L
Secondary
Treatment with
Nutrient Removal*
2-20 Craddock Consulting Engineers
In Association with CDM & James Crook
TM1-Sec2_0707.doc
Tertiary
Treatment with
Filtration
BOD 5-20 5-10