Patent ID: 9169144
Filing Date: 2015-10-27
Classification: B01D,C02F

Abstract:
1. A method of treating water including chemically softening the water, producing hardness crystals, and forming the hardness crystals into ballasts to facilitate the removal of suspended solids from the water, the method comprising: chemically softening the water by mixing a softening reagent with the water in a first reactor and precipitating hardness particles in the first reactor and in a downstream second reactor; directing the water and hardness particles from the first reactor to the second reactor; crystallizing at least some of the hardness particles in the second reactor to form hardness crystals; directing the water and hardness crystals to a clarification unit downstream of the second reactor and separating the hardness crystals from the water to produce a clarified effluent; directing the hardness crystals from the clarification unit to a separator and separating the hardness crystals, by size, into a first stream where a majority of the hardness crystals are relatively small and a second stream where a majority of the hardness crystals are relatively large; mixing the first stream and the hardness crystals therein with the softening reagent and water in the first reactor; mixing the second stream and the hardness crystals therein with the water in the second reactor where the hardness crystals grow; forming at least some of the hardness crystals in the second reactor into ballasts; removing suspended solids from the water by agglomerating the suspended solids, with the aid of a polymeric flocculant, around the ballasts formed by the hardness crystals to form ballasted floc; and separating the ballasted floc from the clarified effluent in the clarification unit.