Strategies for the collective treatment of wastewater and sewage sludge: overview and trends for municipalities in the Puy-de-Dôme department

Abstract

Based on a mail and phone inquiry with 471 municipalities (Communes) of Puy-de-Dôme (France), the study processes strategies of the municipalities for the management of waste water and sewage sludge. The study shows that collective treatment of water and sewage sludge concerns more of ¾ municipalities of Puy-de-Dôme. Between 1993 and 2003, the number of water-treatment plants has doubled to reach 450 units of treatment of the domestic effluents. This recent evolution concerns rather small municipalities, biggest municipalities having set up the collective purification from the seventies. Water purification produces in counterpart sewage sludge, which local volume in 2003 reaches 10 000 tons of dry materials, included liming. The modes of collective treatment of waste water become more and more conditioned by the future of sewage sludge.