WAnaerobic digestion
WAquaver
WAutomatic meter reading
WBubble curtain
WCoagulation (water treatment)
WConcentrated solar still
WDolphin WaterCare
WElectrodialysis
WFilter cake
WFine bubble diffusers
WForward osmosis
WFouling
WMagnetic water treatment
WMembrane
WMercury nano-trap water filtration
WOrganisms involved in water purification
WOsmosis
WRanney collector
WRapid sand filter
WSolar still
WVapor-compression evaporation
WWater jet (recreation)
WWater metering
WWater purification
WWater softening