D.c. Water & Sewer & Authority

District of Columbia Water & Sewer Authority

Walter F Bailey, Jr

Sudhir N Murthy

Eugenio Giraldo

Glen T Daigger

Norman D Dockett

Bernhard Wett

Haydee De Clippeleir

John T Novak

Perry Schafer

Christopher Peot

Leonard Benson

Timothy Constantine

Thomas E Sadick

Dimitrios Katehis

An apparatus and method for selecting, retaining or bioaugmenting solids in an activated sludge process for improving wastewater treatment using screens. The screens can be used to separate and retain solids based on size, compressibility or shear resistance. The screens are used to separate and select slow growing organisms, faster settling organisms, or materials added to absorb, treat or remove constituents in the activated sludge process. A swapping screen arrangement provides another means of selecting various particles. The exposed shear rate or time, particle compression, or SRTs can be adjusted manually and/or automatically in response to detected readings from an instrument such as a spectrophotometer or other optical approaches to optimize selection of organisms. The present disclosure may be configured as an activated sludge system operated at different solids residence times (SRT) for different solids fractions allowing slow growing organisms to get established in competition with faster growing organisms or aggregates thereof.

Method and apparatus for water treatment using screens

An apparatus and method for selecting and retaining solids in an activated sludge process for the improving wastewater treatment using screens. The screens can be used to separate and retain solids based on size or compressibility. The screens are used to separate and select for slow growing organisms, faster settling organisms, or materials added to absorb, treat or remove constituents in the activated sludge process.

Method and apparatus for wastewater treatment using screens

An improved process for sludge treatment includes anaerobic digestion followed by post-mesophilic aerobic and/or anoxic digestion. The first anaerobic step may be performed under either mesophilic or thermophilic conditions. The subsequent aerobic/anoxic digestion may be performed using either simultaneous, sequential or pulsed aerobic and anoxic conditions. An apparatus for performing the improved sludge treatment may be one digester for performing the anaerobic followed by aerobic/anoxic digestion. Alternatively, the system for performing the improved sludge treatment techniques may be at least two digest reactors.

Method for treating raw sludge including a simultaneous or pulsed aerobic/anoxic digestion process

An efficient system and process for removing nitrogen from wastewater while enriching seed sludge in the mainstream treatment process. Bioaugmentation of seed autotrophic organisms facilitate the nitrification reactions by enhancing the rates of reaction advantageously within a smaller volume or within a shorter activated sludge solids retention time. Likewise, bioaugmentation of seed denitrification organisms will also enhance rate of reaction within a smaller volume or shorter activated sludge solids retention time. Separate treatment of high ammonia digester reject water is an efficient method to treat nitrogen in recycle streams as well as to enrich the seed nitrifying and denitrifying cultures.

Method for nitrogen removal and treatment of digester reject water in wastewater using bioaugmentation

Growing community of inventors

Washington, DC, United States of America

Walter F Bailey, Jr