ごみ焼却場の灰汚水貯留槽における硫化水素の発生

抄録

An accident resulting in the inhalation of H₂S, which was generated from the quenching water which cools hot ash, occured at the municipal solid waste incineration plant of H city in 1980. As a result, five workers died suddenly. They entered into the quenching water storage tank to pierce a plugged water pipe without protection masks. At that time, the odor of H₂S in the space of the tank was very weak.
This investigation was done to clarify the cause of accident involving H₂S generation from the quenching water and to consider an inprovement plan for the process. The results obtained are as follows:
1. A large amount of H₂S seemed to be held within the sediments of the water storage tank, and were exhaled rapidly inside the tank when the water storage tank was disturbed by the workers footsteps.
2. It has been clarified that a large amount of sludge containing sulfide was apt to accumulate in a short period to the bottom of each tank, as the reduction efficiency for the sludge in the circulating water was very low in this quenching water treatment process.
3. H₂S in the sludge of the water storage tank was thought to exist as small amounts of foam. Further, it is suggested that the H₂S might be converted from the sulfide in the ash and the added coagulants from the action of bacteria. In addition, the concentration of H₂S in the quenching water, 30% of which was sludge, was considerably higher than the theoretical solubility of the pure water.