US 4,079,003 A · Method of transforming sludge into ecologically acceptable solid material

Abstract

Sludges in the form of aqueous suspensions of organic and inorganic materials that range in viscosity from thick viscous pastes to flowable liquids are produced in the operation of numerous industries and also as waste by municipalities. The apparatus and method of using the same that are the subject of the present invention are directed to transforming the sludge to solids both in sumps in which they may be situated as well as apart from such sumps or storage areas or from continuous sources. The apparatus of the present invention as aqueous sludge is sequentially removed from a sump, storage area, or from continuous sources mixes calcium oxide therewith at a predetermined rate within a confined space. The predetermined rate is such that the exothermic reaction between the calcium oxide and water in the sludge raises the temperature of the sludge-calcium oxide mixture to the extent that substantial steam is produced. The predetermined rate is also such that substantial hydrolysis and saponification of the sludge occurs, and the PH of the sludge-calcium oxide mixture being not less than 12.4. The elevated temperature that occurs in the confined space and the high pH results in the destruction of virus and bacteria in the sludge, and the almost instant destruction of objectionable odors from the sludge. The transformed sludge is in a solid particled state that can be compacted for construction and land fill purposes, and when neutralized may be used for agricultural purposes. Toxic compounds of metals such as cadmium, chromium, arsenic, zinc and the like that were initially present in the sludge are transformed into insoluble compounds by the high pH previously mentioned, and as a result these metals will not leach out when the transformed sludge is used for landfill, roadfill construction or agricultural purposes, and other end uses presently being developed.

Claims15

Dependent claims

A method of transforming aqueous organic material containing sludge that may include virus and odor forming bacteria and toxic soluble compounds that are converted to substantially insoluble compounds in an alkaline environment into a solid, friable, and substantially odor free reaction product, said method comprising the steps of:

a. sequentially moving said sludge from a source thereof at a first rate;
b. sequentially moving calcuim oxide from a source thereof at a second rate, with said second rate so related to said first rate that when sludge and calcium oxide are mixed an exothermic reaction is initialed in which said sludge and calcium oxide react with the evolution of steam to form a solid, friable, substantially odor free reaction product that has a pH of at least 12 and in which bacteria and virus intially present in said sludge are deactivated by said pH and the heat of said exothermic reaction, and said soluble toxic compounds initially present in said sludge are transformed to substantially water insoluble compounds due to the high pH of the mixture of said sludge and calcium oxide as they transform to said reaction product;
c. providing an elongate confined space that has first and second ends;
d. directing said sludge and calcium oxide at said first and second rates into said first end of said confined space;
e. concurrently mixing and moving the mixture of said sludge and calcium oxide in said confined space from said first end towards said second end thereof, with the rate of longitudinal movement of said mixture in said confined space being such that said exothermic reaction has transformed said mixture to said reaction product by the time said reaction product has reached said second end;
f. withdrawing said steam from said confined space;
and
g. sequentially removing said reaction product from said second end of said confined space.

5 more elements

Dependencies are inferred from the claim text.

Method of transforming sludge into ecologically acceptable solid material

Life of this patent

Method of transforming sludge into ecologically acceptable solid material

Life of this patent

Abstract

Claims15