[Removal of residual matter from mixerless sand filters and prevention of growths].
BOLOTNYI
V V
VV
D005374:Filtration; D006801:Humans; D012822:Silicon Dioxide; D014881:Water Supply
D012822:Silicon Dioxide
WATER/supply
Udalenie ostatochnykh zagriaznenii peska skorykh bezmeshalochnykh fil' trov i preduprezhdenie ikh rosta.