D.c. Water & Sewer & Authority

Christopher Peot

Sudhir N Murthy

Glen T Daigger

William Brower

Walter F Bailey, Jr

John T Novak

Perry Schafer

Ronald Alexander

A product, including digestate, that has been pasteurized through thermal hydrolysis, thermal alkaline hydrolysis, or thermal carbonization is cured to enhance its marketability. Variations of this disclosure include embodiments where pasteurized material is inoculated to further enhance marketability where the inoculation is performed by injecting a fungicide, other means of inoculation by injecting beneficial microorganisms to produce characteristics in digestate that are anti-fungal or produce suitable enzyme cofactors or nutrients to stabilize digestate, injections of vitamins to enhance the ability of plants grown using select digestate to thrive in adverse conditions, injection of chemicals to enhance the ability of digestate to retain heat and prevent freezing during wintry conditions, or any combination thereof. Other embodiments include using recycled waste heat generated from wastewater treatment or another process or solar energy for accelerating the drying process which occurs before, during or after curing.

Curing and inoculation of pasteurized digestate

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

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Washington, DC, United States of America

Christopher Peot