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Technical Note: Estrogen Removal from Dairy Manure by Pilot-Scale Treatment Reactors

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Transactions of the ASABE. 53(4): 1295-1301. (doi: 10.13031/2013.32593) @2010
Authors:   Z. Zhao, K. F. Knowlton, N. G. Love, J. A. Ogejo
Keywords:   Dairy manure, Dairy manure treatment, Endocrine disrupting compounds, Estrogen removal

Accumulation of estrogens in the environment is of concern because they disrupt the endocrine system of sensitive species. Livestock manure contains significant estrogens. We evaluated removal of 17-estradiol (E2) and total estrogenicity (E2-eq) from dairy manure in pilot-scale reactor systems designed to remove ammonia or to generate methane: two were aerated (60% and 100% aeration), one was an anaerobic digester, and one was a nitrifying reactor receiving anaerobically digested manure. In all reactors, the influent contained more E2 and E2-eq than the effluent. Orthogonal contrasts were conducted to compare efficiency and rate of estrogen removal between reactors. The most consistent improvement in estrogen removal was associated with aeration and ammonia oxidation; reactors with varying levels of aeration and with high ammonia removal efficiencies removed estrogens faster and to a greater extent than those without. Anaerobic digestion pretreatment did not correlate with increased extent of estrogen removal in a downstream, fully aerated nitrifying reactor, but it did increase the rate of estrogen removal in the downstream reactor. Additional experiments evaluated a reactor designed to achieve low dissolved oxygen (DO) nitrification/denitrification, and one performing enhanced biological phosphorus (P) removal. While differing feed sources in the two sets of experiments prevent direct comparison, low DO denitrification achieved similar or greater removal of E2 and E2-equivalents as compared to fully aerated systems. Manure treatments designed to achieve nutrient removal or to generate methane have significant potential to reduce estrogen loading from dairy farms.

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