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. Conclusions: 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.