Recycling Treated Municipal Wastewater for Industrial Water Use

Craddock Consulting Engineers 1
In Association with CDM & James Crook
TM2-Sampling_0707.doc
Technical Memorandum 2
Sampling Plan and Results
1.0 Introduction
This technical memorandum is the second in a series of memoranda developed under
a Metropolitan Council (Council) project titled “Recycling Treated Municipal
Wastewater for Industrial Water Use.” Funding for this project was recommended by
the Legislative Commission on Minnesota Resources (LCMR) from the Minnesota
Environment and Natural Resources Trust Fund. The Council is providing additional
funding for the project through in-kind contributions of staff time. Other state
agencies are participating via stakeholder meetings and technical review and input.
The project proposal to LCMR included the provision for the sampling of Council
WWTPs if early project tasks determined that additional information was needed.
Following completion of Task 1 of the project in June 2006, it was decided that the
project would benefit from a better characterization of water quality constituents of
concern applicable to a range of industries. This memorandum documents the
sampling plan and the results.
1.1 Objectives
The goal of the sampling program was to define the concentrations of constituents of
concern for industrial water use practices that are the more dominant uses of water in
the state of Minnesota and for which use of reclaimed water is more likely. The
sampling program targeted constituents that are not typically monitored in WWTP
effluent.
1.2 Constituents of Concern
The historic water quality record of WWTP effluent is extensive for constituents of
concern to the receiving waters. These constituents include carbonaceous or total
biochemical oxygen demand (CBOD, TBOD, or BOD), total suspended solids (TSS),
ammonia (NH3), total phosphorus (TP), and fecal coliform. These parameters are also
important in characterizing the effluent quality and applicability for industrial use.
However, there are many other constituents of concern for industrial applications and
the majority of these are not commonly characterized in municipal WWTP effluent.
Additional sampling is needed to accurately define the concentrations of these
constituents in the WWTP effluent.
The industrial demand analysis of Technical Memorandum 1 of this project, titled
“Implementation Issues and Customer Inventory”, identified the major uses of water
by industries in Minnesota and in more detail for the Minneapolis/St. Paul
metropolitan area (metro area). One significant use of water in Minnesota is for
cooling at power generation facilities and for other industrial processes. Use of
reclaimed water for cooling water is common in states with established wastewater