Patent ID: 6228269
Filing Date: 2001-05-08
Classification: C02F,Y10S

Abstract:
A method for treating a quantity of wastewater comprising dissolved heavy metals and photoresist polymer, paint waste, or other constituents that if untreated would render said wastewater unfilterable, to produce a sludge containing at least said dissolved heavy metals and detackified solids that can be filtered from said quantity of wastewater, comprising the steps of:acidifying said wastewater as needed to reach a pH of no more than about 5.0, so as to precipitate out photoresist polymer, paint waste, or other constituents that if untreated would render said wastewater unfilterable;adding an iron salt and a sulfide reacting product to said wastewater at a dosage of at least about 1,000 ppm to precipitate a sludge comprising iron sulfides, sulfides of said heavy metals, and detackified solids; andfiltering the sludge from the wastewater.