Degradation of organochlorine compounds in spent sulfite bleach plant effluents by actinomycetes

Abstract

Actinomycetes isolated from different soil samples were tested for their abilities to utilize spent sulfite bleach effluents from a paper mill. Degradation and dechlorination of the chlorinated compounds in the effluents of the first two bleaching stages, i.e., chlorination stage [(C + D)(red.)] and alkaline extraction stage (E1O), were monitored by determining total organic carbon (TOC) and activated-carbon-adsorbable organic-bound halogen (AOX). The isolates showed increased degradation rates after repeated incubations in the effluent-containing medium. Separation of the culture supernatants by ultrafiltration into three fractions of different molecular weights revealed substantial AOX and TOC reductions in the low-molecular-weight fraction. The AOX values of the higher-molecular-weight fractions were also reduced. Extracellular peroxidase and cell wall-bound catalase activities were produced during growth of the microorganisms on bleach effluents.