The terms “constructed wetland” and “reed bed” are usually used interchangeably. The principle is simple: wastewater is first freed from solids, then it runs through a soil filter of granular substrate. On the grains microorganisms grow developing colonies and decompose the organic pollution load. The rhizome of the inserted plants is hollow which keeps the filter permanently permeable. This all takes place beneath the reed bed’s surface. The purifying process is odorless, even in permafrost and extreme hot and dry periods.
Constructed wetlands purify domestic sewage from remote hamlets as reliable as wastewater from smaller municipalities and farming.