Crown, Julia

Julia Crown works for Clean Water Services in Washington County, Oregon, on wastewater regulations. She is an alumna of Portland Community College, Simmons University, and Oregon State University and holds degrees in biology and bioresource engineering. She previously worked for the City of Gresham in the Industrial Pretreatment Program and at Oregon DEQ developing TMDLs and analyzing data for the Pesticide Stewardship Program.

Titles from this speaker

Effects of Removing Tertiary Alum Treatment on Tualatin River Water Quality

Abstract

The Tualatin River has had a phosphorus TMDL since 1988 that requires Clean Water Services (CWS) to add tertiary alum at its two advanced water resource recovery facilities (WRRFs) in the summer to meet stringent effluent limits for total phosphorus. Over several decades, management of the river has changed dramatically, especially flow management. U.S. EPA recently finalized new aluminum criteria in Oregon that challenges the use of alum in the tertiary process at current application rates to control phosphorus. CWS conducted a study in which tertiary alum addition at the WRRFs was ceased and the resulting effects on the river were monitored and modeled. While the total phosphorus concentrations in the effluent were higher than they are with alum use, the study demonstrated that the increase in total phosphorus concentration did not negatively impact water quality in the river.

Clean Water Services (CWS) demonstrated through experiments and modeling that river conditions have changed since the conditions in the 1988 TMDL that produced stringent effluent phosphorus limits for WRRFs, and river water quality can be maintained with higher effluent phosphorus concentrations. For three summers, CWS monitored the aluminum, pH, and chlorophyll-a response in the river which showed the ability to maintain water quality standards in the Tualatin River.

SpeakerCrown, Julia

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionNutrient Management: Growing Water Quality

Session locationRoom S504a - Level 5

TopicIntermediate Level, Nutrients, Watershed Management, Water Quality, and Groundwater

Author(s)

J. Crown