Abstract

In a batch culture laboratory aeration system it was found that when lime sulphide effluents were aerated in the presence of manganese a large proportion of the sulphide was oxidised to a form still having an oxygen demand which could revert to sulphide under anaerobic conditions. Aeration of lime-sulphide effluent after neutralisation results in the sulphide being lost from the effluent, yielding an effluent with a lower oxygen demand. The percentage oxygen demand reduction obtained on aeration improved when the initial strength of the effluent was reduced.