MICROBIOLOGICAL STUDY OF A BLEACHED KRAFT PULP-MILL AERATED LAGOON

Pulp mill aerated lagoons are subject to perturbations owing to the changing composition of the effluent and variations in climate. Such stresses may affect microbial activity and the biodegradation of chlorinated organic compounds. Studies revealed that variation in the culturable microbial population in a northern Ontario kraft pulp mill lagoon is related to process parameters (wood type and temperature). Although organochlorine removal was found not to vary seasonally in a previous study of the same lagoon, the occurrence of lagoon effluent toxicity during the winter months corresponded with declining temperature and numbers of viable bacteria in the aeration stabilization basin.