Patent ID: 7429329
Filing Date: 2008-09-30
Classification: C02F,Y02W,Y10S

Abstract:
1. A hybrid chemical/mechanical dewatering sewage treatment method for conventional mechanically dewatered treatment plants having wastewater inflow streams, which can also be chemically dewatered to effectuate separation of solids from wastewater comprising: a. diverting for chemical dewatering a portion of wastewater stream inflows and/or mechanically dewatered solids, wherein the portion to be chemically dewatered is greater than 0% and up to 100% based on at least one of the following factors: determined by: 1. inputting into a computer a database of the costs and revenues of a wastewater treatment plant consisting of: 2. inputting into the computer a software program that calculates net revenues and costs of various combinations of wastewater treatment unit processes, 3. computer calculating net costs of expanding the existing sewage treatment plant using similar existing mechanical methods, and off-setting revenues, 4. inputting into the computer a database of the chemical concentration and dewatering costs to meet expansion needs of the plant to meet current permitting objectives, added revenues from sales of treated water, avoidance of landfill costs and other benefits associated with chemical concentration and dewatering costs, 5. computer calculating net costs of chemically dewatering expansion capacity required of the existing plant, 6. computer comparing net costs of expanding the existing sewage treatment plant using existing mechanical technology with net costs of chemical concentration and dewatering costs to provide for this expansion need, and 7. computer selecting and designing a combined system employing both mechanical and chemical concentration and dewatering technology to effectuate a combined wastewater treatment rate within budget constraints to determine said portion; b. chemically treating the diverted portion of the wastewater stream inflows and/or mechanically dewatered solids with anhydrous or hydrous SO2 to separate the solids from the wastewater, c. disposing of chemically separated solids in accordance with sewage treatment plant disposal unit processes and/or permit requirements, and d. disposing of chemically treated water consistent with sewage treatment plant discharge permits or by reinjecting it into desired disposal unit processes of a sewage treatment plant in a manner which will not interfere with any conventional aerobic and anaerobic digesters to prevent the killing of helpful bacteria within the digesters, and/or permit requirements.