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:
Apr. 12, 1977
Filed:
Jan. 26, 1973
Orris E Albertson, Norwalk, CT (US);
Dorr-Oliver Incorporated, Stamford, CT (US);
Abstract
A process and apparatus for economically removing algae producing phosphorus, from sewage by separating sludge from the sewage, recirculating the sludge, mixing into this the lime needed to bring the pH up to 11.0 or more and then mixing the limed sludge with the raw feed to a pH of 10.5 or under to precipitate more phosphorus from the total flow than would result from an equal amount of lime fed directly into the total flow. This result is also obtained by splitting the feed and heavily dosing one part with lime before returning it to the remainder of the feed. The high pH reached in the heavily dosed part also produces a water softening effect, which makes the sludge easier to dewater and the effluent more acceptable for discharge or reuse. Additional precipitation is economically secured by mixing polyvalent metal salts or polyelectrolytes with the lime treated waste material before separation of the lime sludge from the waste material effluent.