US 5,744,037 AGranted

Method of treating foul water

AssigneeEbara Corporation

InventorsHiroyuki Fujimura, Takayuki Suzuki, Norio Yamada, Yoshiyuki Ichiki

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Abstract

In an improved method of treating foul water, the solids that are produced during the process of treatment of foul water such as wastewater or liquid sludges are treated with a heat treatment apparatus and the resulting thermal energy and/or gas is utilized in the treatment of said foul water. The foul water may be subjected, directly and/or after a treatment, to a filtration step using a filter packed with nonflammable particulate matter such as sand, and the trapped solids are fed into a fluidized-bed heat treatment apparatus such as a fluidized-bed incinerator or gasification furnace and, thereafter, the nonflammable particulate matter in the heat treatment apparatus is returned to the filtration step. The foul water can be treated with effective utilization of the energy of the organic matter in the foul water or the solids that are produced during the process of its treatment.

Claims14

Dependent claims

A method of treating foul water comprising at least one of night soil, septic sludge and sewage, which comprises:

(a) feeding the foul water into a first chamber, where it is detained to remove sand and gravel;
(b) holding effluent from said first chamber temporarily in a receiving tank and forcing it through a pretreatment screen, whereby the effluent is separated into a solid portion and a liquid portion;
(c) sending the solid portion to a dewatering apparatus, from which dewatered screenings emerge;
(d) introducing separated water into an anaerobic digestion treatment apparatus, or biological denitrification treatment apparatus, or activated sludge treatment apparatus, whereby treatment is conducted to produce digested sludge or excess sludge;
(e) introducing the digested sludge or excess sludge into a sand filtration tank having a sand layer and an underlying gravel layer;
(f) combining sludge trapped with sand of said sand layer, sand removed by detention in the first chamber, dewatered screenings from a screenings dewatering apparatus, waste materials comprising scrap tires and domestic organic wastes to form a mixture, fluidizing the mixture to form a fluidized layer, and burning the mixture in a fluidized-bed heat treatment apparatus;
(g) after burning the sludge in the fluidized-bed heat treatment apparatus, feeding sand from the fluidized layer into a separator to separate said sand, and recycling the resultant separated sand to said sand filtration tank.

4 more elements

A method of treating foul water comprising at least one of night soil, septic sludge and sewage, which comprises:

removing solids from the foul water to provide a solid portion and separated water;
introducing said separated water into an anaerobic digestion treatment apparatus, or biological denitrification treatment apparatus, or activated sludge treatment apparatus, whereby treatment is conducted to produce digested sludge or excess sludge;
introducing the digested sludge or excess sludge into a sand filtration tank having a sand layer and an underlying gravel layer;
combining sludge trapped with sand of said sand layer, said solid portion, and waste materials comprising scrap tires and domestic organic wastes to form a mixture, fluidizing the mixture to form a fluidized layer, and burning the mixture in a fluidized-bed heat treatment apparatus;
after burning the sludge in the fluidized-bed heat treatment apparatus, feeding sand from the fluidized layer into a separator to separate said sand, and recycling the resultant separated sand to said sand filtration tank.

2 more elements

Dependencies are inferred from the claim text.