Biodegradation of synthetic detergents evaluation by community trials Part 2: Alcohol and alkylphenol ethoxylates

The biodegradability of ethoxylates based on synthetic primary alcohols and on iso‐octylphenol has been evaluated by field trials with a trickling filter sewage treatment plant serving a small community. Ethoxylates based on synthetic alcohols showed good biodegradability in the trickling filter even in winter. This is in line with laboratory tests. Effluents were practically nonfoaming and on further aeration an ultimate biodegradability of 99% was achieved. Ethoxylates based on iso‐octylphenol biodegraded in winter to an extent of some 20% only. In summer, values as high as 80% were obtained. In general however ethoxylates of this type cannot be considered biodegradable. Effluents showed a considerable tendency to foam even under summer conditions.