Abstract
Laboratory wastes at The University of Tokyo are supposed to be collected and discarded to the university’s Environmental Science Center. However, in 2009, two incidents of inappropriate drainage occurred in the Engineering buildings. In one case, 10 liters of aqua regia was spilled in the fume hood to be discharged into sewers. Aqua regia is a strong acid that can generate hydrogen sulfide in the sewers, thus posing a serious threat to sewer workers. The Bureau of Sewerage, Tokyo Metropolitan Government, requested the university to undertake structural measures to prevent future discharges of acid waste directly into sewers.Considering the cost of installation, three types of preventive equipment—hand-operated valves, electromagnetic valves with foot switches, and drain tanks with hand-operated valves—were installed as structural measures, and compared with regard to utility,convenience, and operational issues. The drain tank is useful in most cases, and a hand-operated valve is adequate where only a small amount of wastewater is discharged. The preventive equipment have been installed in the Engineering buildings because of the risk assessment addressed by the laboratories. The equipment can provide protection only when appropriately used. Through introducing a safety management system (SMS) to all the Engineering laboratories and conducting risk assessments, the risk of a drainage incident has been reduced. Introducing SMS as part of education and training at the university laboratories seemed useful in improving awareness of drainage incidents and in preventing them.
