Use of ATP to identify poor-performing filters

Al ParrellaWestern Lake Superior Sanitary District

Duluth, MN

Add bleach here

Final effluent

Problem statement:

• Bacteria increases across effluent filters– Seems to be a seasonal phenomenon

(worse towards end of season)

Fecal coliform, before and after filtersMonthly geometric mean

April May June July August SeptemberOctober0

50

100

150

200

250

300

350

400

450

BeforeAfter

Fecal coliform, before and after filtersMonthly geometric mean

April May June July August SeptemberOctober0

50

100

150

200

250

300

350

400

450

BeforeAfter

Problem Limit

Troubleshooting

• Use of ATP pen• Test ATP at various location including the

effluent of each filter• Results reported as difference between “total”

and “free”

Secondary

Effluen

t

Floc T

ank In

fluent

Filter

Effluen

t 1

Filter

Effluen

t 2

Filter

Effluen

t 3

Filter

Effluen

t 4

Filter

Effluen

t 5

Filter

Effluen

t 6

Filter

Effluen

t 7

Filter

Effluen

t 8

Filter

Effluen

t 9

Filter

Effluen

t 10

Filter

Effluen

t 11

Filter

Effluen

t 12

Final

Effluen

t0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

ATP Assessment October 2, 2013

Results

• Clearly there was a problem with number 11 filter

• Found several mechanical issues related to backwash system

Secondary

Effluen

t*

Floc T

ank In

fluent

Filter

Effluen

t 1

Filter

Effluen

t 2

Filter

Effluen

t 3

Filter

Effluen

t 4

Filter

Effluen

t 5

Filter

Effluen

t 6

Filter

Effluen

t 7

Filter

Effluen

t 8

Filter

Effluen

t 9

Filter

Effluen

t 10

Filter

Effluen

t 11

Filter

Effluen

t 12

Backwash

Wate

r

Final

Effluen

t0

500

1000

1500

2000

2500

3000

3500

4000

4500

ATP AssessmentOctober 15, 2013

Conclusion

• It’s hard to clean 100+ tons of media

Steps

• Start meter• Obtain sample• Submerge pen• Break ampule• Mix• Obtain reading– Units are in “relative light units”

Thanks to…

• …Roger Sandstrom, Treatment Plant Operator• Kathy Hamel, PE, Operations and

Maintenance Supervisor, Clean Water Production