2013 Ammonia Criteria Update

Tom Wallace

Geosyntec Consultants

REGFORM Water Seminar

September 5-6, 2013

Columbia, Missouri

New vs. Old

Criteria magnitudes are expressed as total ammonia nitrogen (mg TAN/L) at pH = 7.8 and 26˚C. Criteria assume

Oncorhynchus spp. absent, early life stages (ELS) present, and Unionid mussels present.

Acute Ammonia Criteria

Lasmigona subviridis, Green Floater

Epioblasma capsaeformis, Oyster mussel

Villosa iris, Rainbow mussel

Lampsilis sp., River mussels

Normalized to pH 7.0 and 20˚C

Chronic Ammonia Criteria

Lampsilis spp., Wavy-rayed lamp mussel and

Fatmucker

Villosa iris, Rainbow mussel, Oyster mussel

Lepomis spp., Bluegill and Green sunfish

Musculium transversum, Long fingernailclam

Normalized to pH 7.0 and 20˚C

Potential Permit Limits

Small lagoon

Big River

Max dilution

ZID = 10 x DAF

Small stream

WWTF

Zero Dilution

Typical Ammonia Effluent

Flexibilities for States Applying EPA’s

Ammonia Criteria Recommendations

Recalculation Procedure for Site-Specific

Criteria Derivation

Site-specific pH and

Temperature?

Variances

Revisions to

Designated Uses

Dilution Allowances

Compliance

Schedules

Mussel Surveys

Objective – Determine

presence or absence of

Order Unionoida

Downstream extent subject

to ammonia impacts

Site-specific criteria

development:

Recalculation Procedure, or

Mussel absent criteria

(Appendix N)

Subject to EPA review

Distribution of 29 Common Mussel Species

from Order Unionoida

Source: MDC (1999), Missouri’s Freshwater Mussels

When may permits be affected?

New plants and plants with

currently planned ammonia

removal requirements

Now

All existing plants with

ammonia limits

Following adoption by Missouri

and as permits are re-issued.

Existing Plants with

Monitoring Only

Depending on the effluent data

Summary Points

The new ammonia criteria is out and it’s more stringent.

With no dilution or mixing zones (end-of-pipe), the likely average monthly limits will be:

Summer: 0.6 mg/L….down from 1.4 mg/L

Winter: 2.2 mg/L…..down from 2.9 mg/L

Wastewater plants may struggle to consistently meet effluent limits based on the new criteria.

There are flexibilities to conduct site-specific studies that may potentially support higher effluent limits.

Timing will hinge on the current need to add ammonia removal, Missouri’s adoption of the criteria, and permitting cycles.

Thank You!

For further information:

Tom Wallace

Geosyntec Consultants

1123 Wilkes Blvd., Suite 400

Columbia, Missouri 65201

Phone: 573.443.4100

Email: twallace@geosyntec.com