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:
Mar. 01, 1994
Filed:
Nov. 12, 1992
Joseph Dorica, Pointe Claire, CA;
Steven Prahacs, Beaconsfield, CA;
Pritham Ramamurthy, Montreal, CA;
Pump and Paper Research Institute of Canada, Pointe Claire, CA;
Abstract
A process is for removal of suspended solids including resin and fatty acids from pulp mill effluents including Chemi-Thermo-Mechanical Pulp (CTMP) mill effluents. The process involves filtration of untreated or primary treated effluents through a mat of primary sludge, pulp or woodroom sludge. A sludge mat is formed on a wire screen or punched drum and the effluent to be treated is filtered through the mat. Most of the suspended solids and a part of colloidal material and dissolved solids are retained by the mat. Following the filtration stage, the sludge is dewatered and removed. A portion of the sludge is recycled to form the mat for the next filtration cycle, while the excess sludge is purged. The filtration is achieved by the application of vacuum below the filter mat or pressure over mat. The process will produce treated effluent with low suspended solids and sludge at high solids consistency and eliminate the need not only for a clarifier but also for sludge thickening and filtration units often used in pulp mills. Calcium chloride may be added to the effluent prior to primary settling or before filtration, to enhance the removal of suspended and total solids.