Conservation of Nitrogen via Nitrification and Chemical Phosphorus Removal for Liquid Dairy Manure

dc.contributor.authorDeBusk, Joen
dc.contributor.committeechairOgejo, Jactone Arogoen
dc.contributor.committeememberKnowlton, Katharine F.en
dc.contributor.committeememberLove, Nancy G.en
dc.contributor.departmentBiological Systems Engineeringen
dc.description.abstractThe objectives of this study were to (1) determine an intermittent aeration strategy that could be used to conserve nitrogen (N) via nitrification in dairy manure, (2) determine the effect of recycled flush water on the bio-availability of N during nitrification, and (3) determine effective and economical dosages of chemicals to remove phosphorus (P) from liquid dairy manure. Intermittent aeration strategies, defined in terms of time the aerator is on and off (ON h:OFF h), could be used to conserve N in dairy manure. Testing of four treatments (continuous aeration [100%], 1h:0.33h [75%], 1h:0.67h [60%], and 1h:1h [50%]) showed that only treatments using air provided for 100% and 75% of the time could support nitrification. The 100% and 75% aeration treatments conserved an average of 38% and 25% of influent total ammonia nitrogen (TAN) as nitrite-N+nitrate-N, respectively. Less than 2% of influent TAN was conserved using 60% and 50% treatments. The effect of manure handling technique on N bioavailability and nitrification was tested using flushed and scraped dairy manure. Nitrification was inhibited in scraped manure. Four aluminum- and iron-based salts and five cationic polyacrylamide polymers were evaluated for P removal using jar tests. Ferric chloride (FeCl3·6H2O), aluminum sulfate (Al2[SO4]3·13H2O, alum), and Superfloc 4512 were selected for further study. Polymer addition enhanced floc size and improved P removal. Treatment of manure (0.89% total solids) from Tank 2 at Virginia Tech's dairy using either FeCl3 or alum in combination with polymer resulted in more than 90% P removal. Chemical treatment and transport of P-rich sludge from a 2,270 cubic meter storage tank would result in an estimated 40% cost savings over transport of the entire manure volume offsite for land application elsewhere. The manure treatment strategies tested provide some solutions to dairy farmers regarding adjustment of N:P ratios so that manure can be applied to meet nutrient needs of crops while adhering to regulations set forth by nutrient management plans.en
dc.description.degreeMaster of Scienceen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.subjectdairy manureen
dc.subjectcationic polyacrylamideen
dc.subjectnitrogen conservationen
dc.subjectchemical phosphorus removalen
dc.subjectferric chlorideen
dc.titleConservation of Nitrogen via Nitrification and Chemical Phosphorus Removal for Liquid Dairy Manureen
dc.typeThesisen Systems Engineeringen Polytechnic Institute and State Universityen of Scienceen


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