Patent ID: 7105094
Filing Date: 2006-09-12
Classification: B01D,C02F,Y10S

Abstract:
1. A method for removing high concentrations of heavy metals from acidic wastewater comprising the steps of: (a) supplying said acidic wastewater to a first conditioning tank to treat said acidic wastewater; (b) supplying a fifty percent solution of sodium hydroxide to said first conditioning tank; (c) mixing said sodium hydroxide with said acidic wastewater to increase a pH level of said acidic wastewater to a range of approximately 2–4 resulting in a minimal formation of metal hydroxyl compounds within said acidic wastewater; (d) adding a cationic polymer to said acidic wastewater resulting in a formation of flocculate organic matters within said acidic wastewater; (e) transferring said acidic wastewater to a flotation tank; (f) providing air bubbles into said acidic wastewater within said floatation tank which separate said metal hydroxyl compounds and said formation of flocculate organic matters from said acidic wastewater forming sludge within an upper portion of said flotation tank; (g) removing said sludge from said flotation tank; (h) transferring said acidic wastewater having said sludge removed therefrom to a second conditioning tank; (i) supplying said fifty percent solution of sodium hydroxide to said second conditioning tank; (j) mixing said sodium hydroxide with said acidic wastewater to increase a pH level of said acidic wastewater to a range of approximately 5.5–6.5 resulting in a significant formation of copper hydroxyl compound flocs and a minimal formation of nickel and zinc hydroxyl compound flocs within said acidic wastewater; (k) adding said cationic polymer to said acidic wastewater resulting in a first formation of flocculate hydroxyl matters within said acidic wastewater; (l) transferring said acidic wastewater to a first settler wherein said first settler separates and removes said first formation of flocculate hydroxyl matters, said significant formation of copper hydroxyl compound flocs and said minimal formation of nickel and zinc hydroxyl compound flocs from said acidic wastewater; (m) transferring said acidic wastewater having said said first formation of flocculate hydroxyl matters, said significant formation of copper hydroxyl compound flocs and said minimal formation of nickel and zinc hydroxyl compound flocs removed therefrom to a third conditioning tank; (n) supplying said fifty percent solution of sodium hydroxide to said third conditioning tank; (o) mixing said sodium hydroxide with said acidic wastewater to increase said pH level of said acidic wastewater to a range of approximately 7.5–9 resulting in a significant formation of residual heavy metal flocs within said acidic wastewater; (p) adding said cationic polymer to said acidic wastewater and an anionic polymer to said acidic wastewater resulting in a second formation of flocculate hydroxyl matters within said acidic wastewater; (q) transferring said acidic wastewater to a second settler wherein said second settler separates and removes said second formation of flocculate hydroxyl matters and said significant formation of residual heavy metal flocs from said acidic wastewater resulting in substantially clean water exiting said second settler.