Process and composition for water purification

A process for treating water from household laundry comprises separating from a washing and/or rinsing step the waste-water which contains organic and/or inorganic soil, contacting the waste-water with one or more flocculents so as to form flocs, separating the flocs from the waste-water so as to produce purified water and reusing the water. Preferably the process involves a two-stage flocculation where the waste-water is contacted initially with a primary flocculent, eg aluminium ions/polyethylene imines, and then with a secondary flocculent, eg cationic polyelectrolytes. The invention also relates to a water purification composition comprising primary and secondary flocculents, and a kit for supplying unit doses of such flocculents.