Copper Sequestration Using Local Waste Products

Ippolito, J.A. (2010) Copper Sequestration Using Local Waste Products. pp. 33-34. Proceedings of the Idaho Nutrient Management Conference, March 9, 2010, Shoshone, Idaho.

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Abstract

Dairies utilize copper sulfate (CuSO4) foot baths to control hoof infections. Typical
solutions are 5 or 10% CuSO4 (pH ~6), equal to 12,500 or 25,000 ppm Cu, respectively. When
spent, hoof bath solutions are usually disposed of in waste lagoons and subsequently utilized for
irrigation. In the Magic Valley, this practice appears to be causing soil Cu concentrations to
increase. The goal of our research was to use local waste products to sequester Cu from a
simulated hoof bath solution and to use waste products to adsorb excessive Cu from Cu-affected
soils.

We utilized lime waste and fly ash from the Amalgamated Sugar Company, LLC (Twin
Falls, ID) to identify Cu sorption maximum as a function of pH. In triplicate, solutions
containing one gram of material and increasing Cu concentrations (0, 2500, 5000, 12500, 25000
ppm Cu) were shaken for one month buffered at either pH 6, 7, 8, or 9. Materials shaken at pH 6
adsorbed the greatest amount of Cu, but concentrations up to 25000 ppm did not maximize all
adsorption sites. Thus, additional solutions containing waste materials and Cu concentrations of
75000 and 100000 ppm Cu were shaken for one month at pH 6. Results showed that at pH 6
lime waste and fly ash adsorbed a maximum of ~ 45000 and 26000 ppm of Cu. The use of lime
waste to sequester Cu from spent dairy CuSO4 hoof baths appears to be a viable option.

Because lime waste adsorbed a greater quantity of Cu as compared to fly ash, we
investigated the ability of lime waste to sequester Cu from Cu-affected soils. A soil from the
Logan Soil Series (Typic Calciaquoll; pH 8.0; CEC = 14 meq/100g; % lime = 50%) which had
received 0, 250, 500, or 1000 ppm Cu approximately one year earlier was utilized. Using a
completely randomized design with four replicates, lime waste was applied at 0, 0.5, 1, and 2%
by weight (~0, 10, 20, and 40 tons/acre), thoroughly incorporated, and allowed to incubate at
90% of field capacity for 3 months, after which 15 alfalfa (Medicago sativa L.) seeds were
planted in each pot. Plants were allowed to grow for 2.5 months, and then were harvested at ½”
above the soil surface, oven dried at 60oC for 72 hours, ground, weighed, and analyzed for total
Cu content. Soils were air-dried, ground to pass a 1/16” screen, and then
diethylenetriaminepentaacetic acid (DTPA; a measure of plant-availability) extractable Cu was
measured. Soils were also subjected to a sequential metal extraction procedure which identified
Cu associated with a) soluble species, carbonates, and cation exchange sites, b) iron and
manganese oxyhydroxides, c) organic matter and sulfides, and d) residual phases. Increasing soil
Cu application rate decreased alfalfa yield, but increasing lime waste application rate had no
effect on improving alfalfa yield. Increasing soil Cu application also increased plant Cu
concentration, while increasing lime application rate caused a decrease in plant Cu concentration.
Increasing soil Cu application increased DTPA extractable Cu content, while increasing lime
application rate did not affect extractable soil Cu content. Increasing Cu application rate
increased Cu bound in all soil phases. Lime waste significantly affected Cu associated with most
soil metal phases, but the changes were not large enough to help decrease soil Cu concentrations
to below levels that would affect alfalfa growth and Cu accumulation. The use of lime waste to sequester Cu from Cu-affected soils, unlike from solution, does not appear to be a viable treatment process. Results of these studies will be published in a peer reviewed journal later this
year.

Item Type:	Conference or Workshop Item (Paper)
NWISRL Publication Number:	1349
Subjects:	Animal
Depositing User:	Users 6 not found.
Date Deposited:	27 May 2010 02:37
Last Modified:	13 Oct 2016 20:29
Item ID:	1382
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1382

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