vidange d'un étang aéré

CONT: Le montant du fonds de réserve concernant la vidange des étangs aérés doit être utilisé aux fins pour lesquelles le fonds a été constitué.

OBS: drain (v.): To draw off or away (a liquid) gradually, or in small quantities, by means of a conduit or the like; to carry off or away by means of a drain.
OBS: When ponds are drained, the quantities of nutrients and organic matter in the water that is discharged are ... much less than the total waste loading to the pond. Increasing the interval between pond drainings simply makes fuller use of the ""waste treatment"" capability of the pond ecosystem by allowing natural processes to remove more wastes from the water before discharging the water.
OBS: Static systems do not receive continuous water inflow. They rely either on low biomass or natural processes within the system to maintain water quality with occasional additions of new water when required. Most ponds are run as static systems. Water exchange is often achieved by partially draining the pond or tank and then replacing lost water.