Recycling Treated Municipal Wastewater for Industrial Water Use

Appendix B
Status of Water Reuse Regulations and Guidelines
In the few states that have adopted regulations for reclaimed water use in wetlands,
requirements vary based on type of wetland system and degree of public access. For
example, Washington requires that reclaimed water discharged to natural wetlands
where there is no expected human contact with the water must meet Class D reclaimed
water standards (secondary treatment and not more than 240 total coliform (coli)/100
ml), while discharges to natural or constructed wetlands providing human contact
recreational or educational beneficial uses must meet Class A reclaimed water standards
(tertiary treatment and not more than 2.2 total coli/100 ml in the reclaimed water).
Reclaimed water discharged to any wetland system in Washington cannot exceed the
following water quality limits: 20 mg/L biochemical oxygen demand (BOD); 20 mg/L
total suspended solids (TSS); 3 mg/L total Kjeldahl nitrogen (as N); and 1 mg/L total
phosphorus (as P).
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. 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. While many industrial uses require water of higher chemical quality than that
typically present in reclaimed water, e.g., computer chip manufacturing requires reverse
osmosis treatment to produce ultra-pure wash water, water reuse regulations are
intended to provide health protection and only include requirements to attain that end.
Miscellaneous Nonpotable Uses
While all states that have water reuse regulations or guidelines include criteria for crop
and/or landscape irrigation, some include requirements for less common uses of
reclaimed water, such as flushing sanitary sewers, street cleaning, dust control, soil
compaction, making concrete, snowmaking, decorative fountains, commercial laundries,
commercial car washes, equipment washing, and fire protection systems. For these and
similar uses, the various state standards impose wastewater treatment process
requirements, reclaimed water quality limits, and design and operational requirements
reflective of the degree of human exposure to the water that are in concert with other
more common uses of reclaimed water. For example, secondary treatment with a
minimal level of disinfection is acceptable for uses where there is little or no expected
Craddock Consulting Engineers B-8
In Association with CDM & James Crook
WWReuse Tm1_Appendix B_Regulatory.doc