Treatment of surfactant laden wastewater
View Patent ↗Clarification of surfactant laden wastewaters of the type commonly encountered in the laundry, dishwashing, textile manufacturing, and metal cleaning and degreasing processes is provided by use of a chitosan/(meth)acrylyloxy alkyl quaternary ammonium salt graft polymer.
1. A method of reducing the COD of an aqueous medium containing a COD level of >200 ppm based upon 1 million parts of said aqueous medium, said method comprising adding to said aqueous medium an effective amount of coagulant chitosan/(meth)acrylyloxy alkyl quaternary ammonium salt graft polymer (C/MAOA Quat), said aqueous medium having an anionic surfactant level of greater than 50 ppm therein and said aqueous medium comprising a wastewater selected from the group consisting of laundry, dishwashing, textile manufacturing, metal cleaning, and degreasing wastewaters, said C/MAOA Quat being chloride free and having a viscosity of from about 100 cps to about 3,000 cps.
2. A method as recited in claim 1 wherein said C/MAOA Quat is added to said wastewater in an amount of about 4-10,000 ppm, and said C/MAOA Quat is poly-METAS-Chitosan polymer having repeating units of:
wherein A has the formula of:
and wherein n is an integer from 50 to 5000.
3. A method as recited in claim 2 wherein said C/MAOA Quat is added to said wastewater in an amount of about 40-4,000 ppm.
4. A method as recited in claim 2 wherein said wastewater is wastewater from a dishwashing process.
5. A method as recited in claim 2 wherein said wastewater is wastewater from a laundry.