Integrated
sewage or digestible wastes, and fats, oils, greases and waxes (
FOG)
waste treatment methods, systems and facilities include a
slipstream loop incorporating circulation pumps, hot water heat exchangers and conventional anaerobic digesters for continuously circulating actively digesting
sludge at a rate to preclude
solid settlement accumulation as a warm flowable
slurry source. The warmed actively digesting
sludge is pumped from the
slipstream loop through a rock trap into a delivery / input loop both for aiding transport or delivery of
FOG waste to, and for partially filing a closed receiving / conditioning
holding tank, where the warmed actively digesting
sludge softens and liquefies the
FOG wastes offloaded into the
holding tank for further treatment at a desired treatment temperature range (whether psychrophilic, mesophilic, or thermophilic). The contents of the closed receiving / conditioning
holding tank are continuously mixed by a bottom-top recirculation
chopper pump to pre-treat the FOG wastes, liquefying and decreasing solids particle size allowing acidogens in the actively digesting sludge to pre-digest such wastes producing
volatile fatty acids, some
biogas and a highly bioreactive, flowable feedstock
slurry. The produced highly bioreactive, flowable feedstock
slurry can then injected back into the actively digesting sludge
slipstream loop at a controlled rate where the
resultant mixture then is introduced, together with raw
sewage or other digestible wastes, into input or head ends of
waste treatment systems having anaerobic digesters for
digestion of solids and steady-state
methane production. Advantages of the integrated
system relate to a partial
digestion of the FOG in the reaction / holding tank generating
volatile fatty acids that suppress expression of
methane producing methagens in the holding tank, increased steady-state
methane production and significantly reduced solids volume of treated digestible wastes (
sewage) and FOG wastes.