Biodegradable organic carbon in the treated water of the Seine basin purification plants

Abstract

The 1,637 treatment plants located in the Seine river basin were first globally characterized thanks to a Multi Correspondence Analysis based on different parameters: type of process, size in p.e., actual loading, Suspended Solids, Oxydable Matter, nitrogen and phosphorus removal efficiencies. It appears that the actual loading rate does not significantly explain the variability of the efficiencies of removal whereas design capacities are non-linearly correlated to these latter. Based on this statistical description, several treatment plants were selected and their treated effluents investigated by means of 24 hours composite samples. Biodegradable dissolved and particulate organic carbon and Chemical Oxygen Demand were measured. The amount of biodegradable dissolved and particulate organic carbon remaining in treated waters ranged respectively from 1.5 mg/l to 6.8 mg/l and from 0.9 mg/l to 62.1 mg/l.