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United States Department of Agriculture

Agricultural Research Service

2007 Annual Report

1a.Objectives (from AD-416)
Develop and evaluate algal systems for the treatment of dairy and swine manure effluents with respect to: a) capturing N and P from raw and anaerobically digested dairy manure effluents; b) utilization of the algal biomass as an organic fertilizer; and c) overall system nutrient uptake efficiency, operational costs, and potential returns of integrated farm-scale systems. Determine levels and biological effects of oxytetracycline and chlorotetracycline in manure from treated animals on biological treatment processes. Determine levels of antibiotic resistant bacteria in treated manures from animals treated with oxytetracycline and chlorotetracycline. Develop technology and management practices that improve anaerobic digestion of dairy and other animal manure by: a) increasing yield of methane gas; b) increasing energy efficiency of the conversion system; and c) reducing cost. Develop technology to increase the efficiency with which the methane is used to economically meet the energy needs of the farm.

1b.Approach (from AD-416)
Laboratory and pilot-scale field studies will be used to evaluate treatment efficiency and cost of microalgal-based treatment technologies at different loading rates of raw and anaerobically digested manure effluents. Dried algal biomass from manure treatment will be tested in growth chamber studies to evaluate the value of the biomass as an organic fertilizer capable of meeting plant nutrient requirements. Laboratory-scale composting, soil incubation, and anaerobic digestion studies will be used to determine the fates of the antibiotics oxytetracycline, chlorotetracycline, and antibiotic-resistant bacteria in manures from therapeutically treated beef calves. Laboratory and pilot-scale field studies will be used to quantitate effects on methane yield of co-digesting dairy manure with agricultural and industrial by-products. Additional studies will focus on use of cold tolerant microbial consortia to improve the rate and yield of methane production during anaerobic digestion of dairy manure at 10-25 C.

Showed that extractable residues of oxytetracycline (OCT) and chlorotetracycline (CTC) in manure from treated calves rapidly decrease during composting of pilot scale manure piles. Results showed that degradation rates increase with increased temperature within the manure piles. Farmers should be advised of the persistence of OTC and CTC in untreated manure and could compost manure (especially within the first week of treatment) to reduce residues of these antibiotics.

Completed experiments on the effect of manure loading rate on algal total lipid and fatty acid content. Production of algae as a biofuel feedstock has been the subject of research for at least five decades and was a focus of the U.S. Department of Energy’s Aquatic Species Program (ASP) from 1979 to 1995. One conclusion of the ASP was that the most compelling systems would couple an algae-based wastewater treatment system to biofuel production from the resulting biomass. One assumption of this idea is that the entire system would be partially or entirely funded by the value of wastewater treatment. An additional assumption is that the wastewater-grown biomass would contain sufficient levels of fatty acids (FA) to compete with other potential feedstocks. Although there is renewed interest in the algal production of algae for biofuel, there are few reports of the biofuel potential of wastewater-grown algae. The objective of this study was to determine how the fatty acid (FA) content and composition of algae respond to changes in the type of manure, manure loading rate, and to whether the algae was grown with supplemental carbon dioxide. Algal biomass was harvested weekly from indoor and outdoor algal turf scrubber (ATS) units using different loading rates of dairy and swine manure effluents. The results showed that FA content values of the algal biomass ranged from 0.8 to 1.8% of dry weight and showed no consistent relationship to loading rate, type of manure, or to whether supplemental carbon dioxide was added to the systems. Using an approximate value of 1% FA (corresponding to values from the outdoor pilot scale ATS units using raw dairy manure), we estimate a feedstock cost of $130 per kg of algal FA (before extraction and processing). However, within the context of reducing nutrient inputs in sensitive watersheds such as the Chesapeake Bay, ATS treatment costs of roughly $11 per kg N compare very favorably with the costs of other agricultural nutrient management practices. Assuming that extraction solvents could be removed to an acceptable level in the extracted biomass, then sale of the extracted biomass as a slow release fertilizer could also provide a significant source of revenue. If the nutrient treatment and/or fertilizer values are included in the cost analysis, then the feedstock cost per kg FA would be significantly reduced.

Instrumented the BARC dairy anaerobic digester for the evaluation of mass and energy balances and overall performance. Designed and constructed pilot-scale (150-200 gallon reactors) digestion lab for replicated study of codigestion of animal manures with other feedstocks.

Particle board can be heavy/dense and is subject to moisture damage. Adding chicken feather fiber in its formulation adds modulus (strength) to the particle board without adding to its weight/density. Being more hydrophobic than cellulose, feather fiber formulations of particle board are more resistant to moisture and water damage than without feather fiber present. Polymers impregnated with metal ions result in networks that have metallic properties, i.e. they can carry electricity. These properties are transitory for many polymers when metal ions have limited affinity for the polymers. Proteins including feather fiber have multiple charged sites including aspartate, glutamate, lysinate, and arginate. Transition metal ion networks can be formulated with proteins such that metal ions remain as part of the polymer/metal complex over time. Since a charge can be induced in redox transition metals, protein-transition-metal ion networks can be used to create organic batteries as well as organic wires. Protein based polymers could also be used as adsorbents for selectively removing specific ions from solution in the presence or the absence of a current.

5.Significant Activities that Support Special Target Populations

6.Technology Transfer

Number of new CRADAs and MTAs1
Number of active CRADAs and MTAs3
Number of invention disclosures submitted1
Number of non-peer reviewed presentations and proceedings3
Number of newspaper articles and other presentations for non-science audiences4

Review Publications
Westhead, E., Pizarro, C.X., Mulbry III, W.W. 2006. Treatment of swine manure effluent using freshwater algae: production, nutrient recovery, and elemental composition of algal biomass at four effluent loading rates. Journal of Applied Phycology. 18:41-46.

Arikan, O.A., Sikora, L.J., Mulbry III, W.W., Khan, S.U., Foster, G.D. 2005. Composting rapidly reduces levels of extractable oxytetracycline in manure from therapeutically treated beef calves. Bioresource Technology. 98:169-175.

Last Modified: 3/31/2015
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