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ARS Home » Southeast Area » Fayetteville, Arkansas » Poultry Production and Product Safety Research » Research » Publications at this Location » Publication #143494


item Haggard, Brian

Submitted to: North American Benthological Society Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2004
Publication Date: 2/17/2005
Citation: Haggard, B.E., Stanley, E.H., Storm, D.E. 2005. Nutrient retention in a point source enriched stream. North American Benthological Society. 24(1):29-47.

Interpretive Summary: In this report, the ability of a small stream to temporarily retain nutrient inputs from rural wastewater treatment plant was examined in the Eucha - Spavinaw Basin. Often, in the rural landscape the potential nutrient load, impact and contribution from wastewater treatment plants are neglected; the focus is on nonpoint source pollution from the agricultural landscape and land application of animal manure. This report demonstrates the significant impact that the wastewater treatment plant has on its receiving stream, as nutrient concentrations greater than 10 ppm were measured downstream from the wastewater treatment plant. It takes several kilometers for the receiving stream to temporarily retain nutrient inputs from the wastewater treatment. Nutrient retention efficiency was orders of magnitude less than that observed in streams draining agricultural catchments in the Eucha - Spavinaw Basin and also relatively undeveloped basins across the USA. The level of nutrient enrichment from the wastewater treatment plant, seasonal changes and streamflow had substantial effects on nutrient retention in this stream.

Technical Abstract: The ability of a 3rd order Ozark Plateaus stream to efficiently retain nutrient inputs from a rural wastewater treatment plant (WWTP) was examined using the nutrient spiraling concept. Short-term injections are often used to assess nutrient spiraling, where exponential declines in injected nutrients reflected gross nutrient uptake. However, we applied the same mathematical equations to WWTP nutrient additions, where exponential declines in nutrient concentrations reflected net nutrient uptake. We estimated net nutrient uptake length (Snet), mass transfer coefficient (vnet), uptake rate (Unet) and nutrient flux (NF) at Columbia Hollow, Eucha - Spavinaw Basin, northwest Arkansas. Water samples were collected at a reference site upstream of the Decatur WWTP and six sites increasing in distance downstream of the WWTP. The Decatur WWTP had a significant effect on physicochemical properties and nutrient concentrations at Columbia Hollow; maximum phosphorus concentration was over 9 mg L-1 0.3 km downstream from the Decatur WWTP at Columbia Hollow. Net nutrient uptake lengths were generally in the km scale, suggesting several km were required to temporarily retain about 63% of the nutrients from the WWTP. Mass transfer coefficients were 10 times less than values reported in relatively undisturbed streams whereas net nutrient uptake rates were at least 7 times greater. Stream nutrient retention efficiency was significantly related to level of enrichment, seasonal changes and streamflow.