The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 08, 1998
Filed:
Sep. 26, 1996
Richard Alan Haase, Sugar Land, TX (US);
Other;
Abstract
A chemical method is provided for the dewatering of biological sludge that has been digested by a thermophilic digestion process. Four versions of the chemical method are presented. The primary component in the four versions is a polyquaternary amine, preferably of the di-allyl di-methyl ammonium chloride (DADMAC) variety and from the epichlorohydrin di-methyl amine (epi-DMA) variety. By the first method, the polyquaternary amine is added directly, along with a cationic polyacrylamide, to the biological sludge. By the second method, the polyquaternary amine and an anionic polyacrylamide are added separately. By the third method, a quaternized polyacrylamide, having the polyquaternary amine as part of its polymer chain, is produced by copolymerization of acrylamide with monomers of polyquaternary amine quaternization and is added individually to the sludge. By the fourth method, the quaternized polyacrylamide from method three is added in concert with a cationic polyacrylamide to the sludge.