Idaho Recycled Water

Reuse ProgramJune 2015

Reuse Program Summary•1988 – Original rules for Land Application of Wastewater issued•Permit program is funded by Federal Clean Water and State General funds (approximately 50/50)•No permit fees

Reuse Program Summary

• ~130 active reuse permits •73% are municipal and 27% are industrial permits•Over 90% of the reuse permits are agricultural irrigation systems•Remainder are rapid infiltration

Reuse Program Summary

•Approaching 8 billion gallons of water reuse per year•The reuse water contains ~4 million

pounds of nitrogen and ~1 million pounds of phosphorus

Reuse Program Sustainability

• 2011 revisions to the reuse rules allowed DEQ to issue permits for up to 10 years (versus 5 years previously)• This allowed DEQ to “reward” facilities

with good compliance history longer-term permits when permits expired• This has made the permit program

more sustainable with the available staff resources

Reuse Program Sustainability

•Over the past three years, DEQ has issued 59 permits or ~20 permits per year• The average permit term is now up to 6.1

years and will continue to increase as longer term permits are issued• At an average permit term of 6.1 years,

DEQ has to issue 21 permits per year to be sustainable (130 permits/6.1 year permit term)

Simplot Caldwell (Potato Processing Facility)

Simplot Caldwell – Evolution of a Successful Reuse Program• Treatment in the early 1990’s were unlined

anaerobic lagoons located in close proximity to the Boise River• Current treatment system (started up in 2014)

advanced treatment processes membrane bioreactor and filtration (activated sludge with ultrafiltration membranes) and reverse osmosis• Nitrogen loading rates reduced from ~1,500

pounds per acre to agronomic rates

Simplot Caldwell – Evolution of a Successful Reuse Program• The high water quality from the new

wastewater treatment system allows Simplot to return a portion of the treated water for reuse in the potato processing plant

Municipal Reuse Permits• Municipal systems are split into classes

based on treatment and disinfection levels:

Class E

Class D

Class C

Class B

Class A

7%

22%

48%

10%

8%

What We Have LearnedLand treatment of recycled water is not an exact science• Multi-disciplinary – wastewater treatment,

hydrology, geology, agronomy, irrigation, soil science, chemistry, biology, public (neighbor) involvement, land use issues, etc.• Most reuse systems are agriculturally based

activities and gathering and interpreting environmental data takes time (years)

What We Have Learned

• Ground water quality can be difficult to use as a measure of permit compliance• For reuse systems in major agricultural

areas, it may be difficult to determine impacts from the reuse system• Site specific ground water conditions

may not show impacts for many years