Recycling Treated Municipal Wastewater for Industrial Water Use

Appendix B
Status of Water Reuse Regulations and Guidelines
Florida Requirements. Florida requires Class I reliability as defined by the U.S. EPA
[U.S. Environmental Protection Agency, 1974] at water reclamation facilities where
filtration and high-level disinfection are provided. Class I reliability requires multiple
treatment units or back-up units and a secondary power source. In addition, a
minimum of 1 day of reject storage is required to store reclaimed water of unacceptable
quality for additional treatment. Florida also requires staffing at the water reclamation
facility 24 hours/day, 7 days/week or 6 hours/day, 7 days/week as long as reclaimed
water is delivered to the reuse system only during periods when a qualified operator is
present. Operator presence can be reduced to 6 hours/day if additional reliability
features are provided.
Storage Requirements
Current regulations and guidelines regarding storage requirements are primarily based
upon the need to limit or prevent surface water discharge and are not related to storage
required to meet diurnal or seasonal variations in supply and demand. Storage
requirements vary from state to state and are generally dependent upon geographic
location, climate, and site conditions. A minimum storage volume equal to 3 days of the
average design flow is typical in water-short states with warm climates, while more than
200 days of storage are required in some northern states because of the high number of
non-irrigation days due to high rainfall or freezing temperatures.
Most states that specify storage requirements do not differentiate between operational
and seasonal storage. The majority of states that have storage requirements in their
regulations or guidelines require that a water balance be performed on the water reuse
system, taking into account all inputs and outputs of water to the system based on a
specified rainfall recurrence interval.
Reclaimed Water Application Rates
Most state regulations do not include requirements or recommendations regarding
reclaimed water irrigation application rates, as these are generally based on plant or
crop irrigated and site-specific conditions. Of the states that do recommend application
rates, the maximum recommended hydraulic loading rate typically is 2 inches/wk).
Ground Water Monitoring
Ground water monitoring is often required when reclaimed water is used for irrigation
or for impoundments that are not sealed to prevent seepage. In general, the ground
water monitoring programs require that one well be placed hydraulically upgradient of
the water reuse site to assess background and incoming ground water conditions within
the aquifer in question and one or more wells be placed hydraulically down gradient of
the reuse site to monitor compliance with ground water quality requirements. Ground
water monitoring programs associated with reclaimed water irrigation generally focus
on water quality in shallow aquifers. Sampling parameters and frequency of sampling
are generally considered on a case-by-case basis.
Craddock Consulting Engineers B-12
In Association with CDM & James Crook
WWReuse Tm1_Appendix B_Regulatory.doc