Recycling Treated Municipal Wastewater for Industrial Water Use

Section 2
Implementation Considerations
Craddock Consulting Engineers 2-10
In Association with CDM & James Crook
TM1-Sec2_0707.doc
Common Uses. Water reuse regulations focus on public health implications of using
the water, and water quality criteria not related to health protection usually are not
included in water reuse regulations. Most states with extensive water reuse
experience have comparable, conservatively-based water quality criteria or
guidelines. Arguments for less restrictive standards are most often predicated upon a
lack of documented health hazards rather than upon any certainty that hazards are
small or nonexistent. In the absence of definitive epidemiological data and a unified
interpretation of scientific and technical data on pathogen exposures, selection of
water quality limits will continue to be somewhat subjective and inconsistent among
the states. Regulatory requirements for some nonpotable uses of reclaimed water not
included in Table 2.4 are summarized below and detailed in Appendix B.
Wetlands. In most cases, the primary intent in applying reclaimed water to wetlands
is to provide additional treatment of effluent prior to discharge or reuse, although
wetlands are sometimes created solely for environmental enhancement. In such
cases, secondary treatment is usually acceptable as influent to the wetland system.
Very few states have regulations that specifically address the use of reclaimed water
for creation of artificial wetlands or the restoration or enhancement of natural
wetlands. Where there are no regulations, regulatory agencies prescribe requirements
on a case-by-case basis. In addition to state requirements, natural wetlands, which are
considered waters of the United States, are protected under EPA's NPDES Permit and
Water Quality Standards programs. Constructed wetlands built and operated for the
purpose of wastewater treatment generally are not considered waters of the United
States.
Industrial Uses Other than Cooling. Due to the myriad of industrial processes that
use water, regulatory agencies generally prescribe water reuse requirements for
industrial applications other than cooling on an individual case basis. In many cases,
the specific industrial reuse customer will have additional criteria (or more stringent
criteria) than those imposed by the regulatory agency.
Reclaimed water from conventional wastewater treatment processes is of adequate
quality for many industrial applications that can tolerate water of less than potable
quality. Industrial uses of reclaimed water include cooling, process water, stack
scrubbing, boiler feed, wash water, transport of material, and as an ingredient in a
nonfood-related product. Regulatory considerations for reuse of water in industrial
applications include generation of aerosols, safety of manufactured products, and
associated food and beverage production.
For example, Florida regulations address the use of reclaimed water for food processing
at industrial facilities. Florida’s reuse rule specifically prohibits the use of reclaimed
water in the manufacture or processing of food or beverage for human consumption
where the reclaimed water will be incorporated into or come in contact with the food
or beverage product. Similarly, Washington standards do not allow the use of
reclaimed water for food preparation and prohibit its use in food or drink for humans.