Résultats et connaissances acquises grâce à des cultures intensives de microalgues sur lisier de porcherie

Abstract

Many experiments have been carried on at the Muséum national d'Histoire naturelle (Paris) with 7001 tanks to improve the pilot plant built in Château-Thierry during spring 1992. Microscopic green algae belonging to Volvocaceae and Chlorococcaceae have been used for mobilizing nutrients of pig manure. The main species used, Scenedesmus falcatus Chod. and S. quadricauda (Turp.) de Breb., prefer environments enriched with ammonia, the most important nitrogenous part of pig manure. Algal production has often been substantial (up to 315 g DM.m-2.week-1) and removal of ammonia sometimes reached 100 %. However, during winter, production is much lower. A heating system may increase this, but it is still necessary to study the economy of the operation. Excessive zooplankton developments. (Daphnia, Rotifers) induce algal populations to collapse, but it is very easy to avoid this by introducing fishes in tanks and increasing the duration of water retention. © Gauthier-Villars, 1994.