The Role of Micro-organisms in Waste Tip-lagoon Systems Purifying Coke-oven Effluents

S ummary . The population of aerobic bacteria present in the waters of a tip-lagoon system being used to purify a coke-oven effluent has been investigated. Though organisms capable of degrading phenol were detected, the total bacterial population was low, mainly due to a deficiency of orthophosphate and lack of aeration. Phenols can be removed from coke-oven effluents by allowing them to percolate through columns of material from colliery waste tips. Bacteria need not be present for this to occur though the presence of bacteria capable of degrading phenol were detected in the liquid coming from such columns. Only traces of thiocyanate are removed. If a biological filter can be developed, as on columns packed with gravel, better removal of phenols and thiocyanate occurs, but it is doubtful if bacteria play any significant role in the purification of coke-oven waste liquors percolating through large tips of colliery waste.