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LOTT’s Reclaimed Water Study: What we have learned so far about residual
chemicals in our local waters
September 20, 2016South Sound Science Symposium; Shelton, WA
Wendy Steffensen, Environmental Project Manager, LOTTJeff Hansen, Project Manager, HDR
Presentation Outline
•LOTT and the Reclaimed Water Infiltration Study
•Notes on Interpreting Findings
•Task 1 Results (Water Quality Characterization)
•Task 2 Activities (Treatment Effectiveness
Evaluation)
LOTT Clean Water Alliance
Reclaimed Water Infiltration Study
Chemicals in the news Community concerns
Science Scope of Work
Public Involvement Plan
Information
Study ScopingReview of
Background Information
Review of Study Findings
Assessment of
Alternatives
Study Scoping Field WorkAnalysis/Modeling
Assessment of
Alternatives
Primary Study Question
What are the risks from
infiltrating reclaimed water into
groundwater because of
chemicals that may remain in the
water from products people use
every day, and what can be done
to reduce those risks?
Study Framework
1) Water Quality
Characterization
2) Treatment
Effectiveness
Evaluation
3) Risk
Assessment
4) Cost/Benefit
Analysis
• Wastewater
• Reclaimed Water
• Groundwater
• Surface Water
Water Quality Characterization
Study AreasReclaimed Water
Infiltration
No Reclaimed Water Infiltration
Henderson- No
reclaimed
water
infiltration
Hawks Prairie-
Reclaimed
water
infiltration
Study AreasReclaimed Water
Infiltration
No Reclaimed Water Infiltration
Henderson-
No reclaimed
water
infiltration
Hawks Prairie-
Reclaimed
water
infiltration
Regulated Chemicals and Parameters (282)
Unregulated/ Residual Chemicals (127)
• Medicines
• Personal Care Products / Foods
• Hormones
• Household Chemicals
Sampling
Scale / Concentration
Concentration Units Examples
1 part per million (ppm)
1 milligram/Liter (mg/L)
one drop in 10-gallon bucket
1 part per billion (ppb)
1microgram/Liter (µg/L)
one drop in 2 tankertrucks
1 part per trillion (ppt)
1 nanogram/Liter (ng/L)
one drop in 16 Olympic pools
Interpreting Findings: Analytical Challenges
•Low concentrations
•Variability
•Interference from other
organics
Interpreting Findings: Drawing Conclusions
•First step in study
•Soil Aquifer Treatment not characterized
•Detections of chemicals do not equal risk
1) Water Quality Characterization
2) Treatment Effectiveness
Evaluation
3) Risk Assessment
4) Cost/Benefit Analysis
Budd Inlet Reclaimed
Water Plant
Martin Way Reclaimed
Water Plant
Wastewater / Reclaimed Water
Characterization
Number of Residual Chemicals Detected
Martin Way
Reclaimed
Water Plant
Budd Inlet
Reclaimed
Water Plant
Wastewater 52 53
Reclaimed Water 34 29
Residual Chemicals Consistently Detected in Reclaimed Water
Good Removal >85% : n = 4
Example: Atenolol
LOTT: 36-230 ng/L
Other studies: 260-2440 ng/L
Residual Chemicals Consistently Detected in Reclaimed Water
Moderate Removal 33-85%: n = 7
Example: Carbamazepine
LOTT: 190-300 ng/L
Other studies: 97-1600 ng/L
Residual Chemicals Consistently Detected in Reclaimed Water
Poor to No Removal: n = 3
Example: Iohexal
LOTT: 240-14,000 ng/L
Other studies: 41-47,80 ng/L
Groundwater and Surface Water Quality
•Chemicals detected; Groundwater: 22, Surface: 15
•Chemicals with frequent detections at higher levels: Artificial sweeteners, flame retardants, select pharmaceuticals
•Potential sources: septic systems, stormwater runoff, and reclaimed water (where discharged)
Concentrations of Select Residual Chemicals
Concentrations of Select Residual Chemicals
Concentrations of Select Residual Chemicals
Concentrations of Select Residual Chemicals
Concentrations of Select Residual Chemicals
Concentrations of Select Residual Chemicals
Summary of Task 1 Findings
•Some residual chemicals are effectively removed,
while others are fairly recalcitrant.
•Some residual chemicals found in reclaimed water
are also found in the environment, including in
areas with no reclaimed water use.
•Findings in all media are similar to other studies.
Study Framework
1) Water Quality
Characterization
2) Treatment
Effectiveness
Evaluation
3) Risk
Assessment
4) Cost/Benefit
Analysis
What’s Next?
Risk Cost
Questions / Discussion
Wendy Steffensen, Environmental Project Manager, LOTT
Jeff Hansen, Project Manager, HDR
Concentrations of Nutrients
Concentrations of Nutrients
Concentrations of Nutrients
Surface Water Quality CharacterizationDeschutes River Woodland Creek
Mainstem Lower
Mainstem Upper
Beatty Springs
Eagle Creek
Fox Creek
Mainstem Lower
Mainstem Upper
Chambers Creek
Munn Lake
Percival Creek
