In the western US, sugar beet processing for sugar recovery generates a lime-based waste product (~250,000 megagrams/yr) that has little liming value in the region’s calcareous soils. This area has recently experienced an increase in dairy production, with dairies utilizing copper-based hoof baths to prevent hoof diseases. A concern exists regarding soil copper accumulation as spent hoof baths may be disposed of in waste ponds with pond waters utilized for irrigation. The objective of this preliminary study was to evaluate the ability of lime waste to sorb copper. Lime waste was mixed with increasing copper-containing solutions (up to 100,000 mg/kg), at various buffered pH values (6, 7, 8, 9), and shaken over various time periods (up to 30 days). Copper sorption phenomenon was quantified using sorption maximum fitting and sorption mechanism was investigated using X-ray absorption spectroscopy. Results showed that sorption onto lime waste increased with decreasing pH, and the maximum copper sorption of ~40,000 mg/kg occurred at pH 6. X-ray absorption spectroscopy indicated that copper hydroxide was the probable species present, although the precipitate existed as small multinuclear precipitates on the surface of the lime waste. Such structures may be precursors for larger surface precipitates that develop over longer incubation times. Findings suggest that sugar beet processing lime waste can viably sorb Cu from liquid waste streams, and thus it may have the ability to remove Cu from spent hoof baths
