1. Presented by thomas j. Haglund, general manager
UNITENDED CONSEQUENCES OF THE MOST EPIC DROUGHT IN RECORDED HISTORY? Impacts to wastewater systems
Presented by thomas j. Haglund, general manager
Tuolumne utilities district, sonora February 8, 2018

2. Overview of TUD’s sonora regional wastewater treatment facility
The District utilizes approximately 140 miles of pipeline to collect between million gallons of sewage per year (based on average precipitation).

4. Sewer Connections – 6,174 direct, 8,955 total (THCSD and JSD)
A look at the numbers
Sewer Connections – 6,174 direct, 8,955 total (THCSD and JSD)
The original facility was constructed in the late 1970’s
Operates 29 Sewer Lift Stations
Maintains 140 miles of sanitary sewer collection system
Operates two Wastewater Treatment Plants
Maintains 10 miles of Recycled Water Pipeline
100% of the wastewater is recycled

5. Drought related unintended consequences to tud wastewater collection system
29 sewer lift stations in mountainous terrain experienced increased maintenance Due to lower flows
Geography of area created difficult flow scenarios
Increase in solids settling in pipes; increase in blockages
Significant increase in flushing operations to promote flow in collection system
More fats, oils and grease issues
Increase in lateral pipeline work orders
Increase in odors
Increase in root intrusion

6. Lack of water in the system impacts wastewater treatment
Comparison: the peak flow at the regional plant experienced a 35% reduction as a result of extreme conservation measures
Treatment Process: produced higher concentration in wastewater and required water to be recirculated in the system in order to create a balance in the treatment process
Wastewater treatment Operators regulated the flows and added water where needed to adequately process solids
Impacts to agriculture through loss of use of reclaimed water; increased pressure for supplementing with use of raw water supply (district recycles 100% of wastewater supply)

7. Adaptation strategies and financial impacts
Undertaking study for treatment process modifications
Increasing Difficulty in meeting wdr’s
Increased collection system maintenance
Proactive pipe patching and lining projects
Installing odor control filtration
Increased costs are particularly difficult for the significant disadvantaged community (dac) areas the District serves.

8. Water system issues
Age of water concerns in tanks as a result of lower usage
Disinfection by-product management challenges
Higher water temperatures in tanks
Bio film formation
Taste and odor complaints
Gambled with potable supply by trying to gauge use while maintaining lower tank storage levels to overcome problems experienced
Exacerbation of water loss factor in ditches by reducing flow

9. end