of course that not why? ...

of course that not why? marshes, whether it is artificial or natural a whole have problems: stagnant water. that Ci causes light putrefaction in the content. They are water charged in organic waste which often leaves in decomposition by the rot. they are natural biological dustbins. the lixivaits of discharge CAT of level 2 for example are rain water streamings more aprt of the time which on the way recovers all kinds of organic pollution chemical or simply chemical. the stagnant waters of the marshes will not have any action surn this kind of pollution. I am on a project in ivory dimension of a discharge of level 2 which rejects 500m3 surface water. one can do no biological job of treatment of purification on such water. it is necessary that they pass already by a physicochemical system of decontamination (exorbitant and not very effective cost). for any action of biological purification work must start at the origin of the effluent. to avoid any contamination of micro pollutant. After one can do everything for any result. it St besides what occurs nowadays