C CHEMISTRY; METALLURGY
C02 TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
C02F TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
1/00 Treatment of water, waste water, or sewage
C02F1/44 by dialysis, osmosis or reverse osmosis
C02F1/445 by forward osmosis