Co-composting of pharmaceutical wastes in soil.

AIMS Soils at a commercial facility had become contaminated with the pharmaceutical chemical residues, Probenecid and Methaqualone, and required remediation. METHODS AND RESULTS Soil composting was investigated as an alternative to incineration for treatment. In laboratory trials, a factorial experimental design was used to evaluate organic matter amendment type and concentration, and incubation temperature. In pilot scale trials, Probenecid was reduced from 5100 mg kg(-1) to < 10 mg kg(-1) within 20 weeks in mesophilic treatments. An 8 tonne pilot scale treatment confirmed that thermophilic composting was effective under field conditions. In the full-scale treatment, 180 tonnes of soil were composted. Initial concentrations of the major contaminants in the full-scale compost treatment were 1160 mg kg(-1) and 210 mg kg(-1), for Probenecid and Methaqualone, respectively. Probenecid concentration reached the target level of 100 mg kg(-1) in 6 weeks, and removal of Methaqualone to < 100 mg kg(-1) was achieved after 14 weeks. CONCLUSION Co-composting was effective in reducing soil concentrations of Probenecid and Methaqualone residues to acceptable values. SIGNIFICANCE AND IMPACT OF THE STUDY Co-composting is a technology that has application in the remediation of pharmaceutical contaminants in soil.